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  • richardmitnick 11:53 am on December 11, 2014 Permalink | Reply
    Tags: , Fermilab,   

    From FNAL: “How to make a neutrino beam” 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Thursday, Dec. 11, 2014
    Tia Miceli

    line
    Ingredients for a neutrino beam: speedy protons, target, magnetic horn, decay pipe, absorbers. Image adapted from Fermilab

    Fermilab is in the middle of expanding its neutrino program and is developing new detectors to study these ghostly particles. With its exquisite particle accelerator complex, Fermilab is capable of creating very intense beams of neutrinos.

    Our neutrino recipe starts with a tank of hydrogen. The hydrogen atoms are fed an extra electron to make them negatively charged, allowing them to be accelerated. Once the charged atoms are accelerated, all of the electrons are ripped off, leaving a beam of positive protons. The protons are extracted into either the Booster Neutrino Beamline (BNB) or are further accelerated and extracted into the Neutrino Main Injector beamline (NuMI). Fermilab is the only laboratory with two neutrino beams. Our two beams have different energies, which allows us to study different properties of the neutrinos.

    FNAL Booster Neutrino
    Booster Neutrino Beamline

    FNAL NuMI upgrade
    NuMI upgrade

    In the BNB, these protons smash into a target to break up the strong bonds of the quarks inside the proton. These collisions are so violent that they produce new quarks from their excess energy. These quarks immediately form together again into lighter composite short-lived particles called pions and kaons.

    Since the pions and kaons emerge at different directions and speeds, they need to be herded together. As a bugle tunes your breath into musical notes, a horn of a different type rounds up and focuses the pions and kaons. The BNB horn looks roughly like the bell of a six-foot long bugle. It produces an electric field that in turn generates a funnel-like magnetic field, which directs all of the dispersed pions and kaons of positive electric charge straight ahead. Particles with negative charges get defocused. By switching the direction of the electric field, we can focus the negatively charged particles while defocusing the positive charges.

    The focused particles in the BNB beam travel through a 50-meter long tunnel. This is where the magic happens. In this empty tunnel, the pions and kaons decay in flight into neutrinos, electrons and muons. At the end of the decay tunnel is a wall of steel and concrete to stop and absorb any particle that is not a neutrino. Because neutrinos interact so rarely, they easily whiz through the absorbers and on towards the experiments. And that’s the basic formula to make a beam of neutrinos!

    A single neutrino beamline can support many experiments because the neutrinos interact too rarely to get “used up.” The BNB feeds neutrinos to MicroBooNE, and most of them go on through to the other side towards the MiniBooNE detector. Similarly, most of those go on through the other side as well and continue traveling to infinity and beyond. Detectors located in this beam measure neutrino oscillations and their interactions.

    FNAL MiniBoone
    MiniBooNE

    The NuMI beamline is designed similarly, but uses a different target material, two focusing horns, and a 675-meter decay pipe. The spacing between the two NuMI horns is adjustable, allowing fine-tuning of the neutrino beam energy. The NuMI beamline has higher-energy neutrinos than the BNB and thus studies different properties of neutrino oscillations.

    The NuMI beamline feeds neutrinos to the MINERvA experiment and on through to the MINOS near detector. The NuMI beamline then continues about 450 miles through Earth on toward the MINOS far detector in the Soudan mine in Minnesota. By the time the beam reaches the far detector, it is about 20 miles in diameter! By having a near and far detector, we are able to observe neutrino flavor oscillations by measuring how much of the beam is electron neutrino flavor and muon neutrino flavor at each of these two detectors.

    FNAL Minerva
    MINERvA

    The last of the big Fermilab neutrino experiments is NOvA. Its near detector is off to the side of the NuMI beam and measures neutrinos only with a specific range of direction and energy. The NOvA far detector is positioned to measure the neutrinos with the same properties at a greater distance, about 500 miles away in Ash River, Minnesota. By placing the NOvA detectors 3 degrees to the side of the beam’s center, NOvA will get to make more precise oscillation measurements for a range of neutrino energies.

    FNAL NOvA experiment
    NOvA and MINOS far detectors

    As more experiments are designed with more demanding requirements, Fermilab may expect to see more neutrino beamline R&D and the construction of new beamlines.

    See the full article here.

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    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics.

     
  • richardmitnick 12:46 pm on December 9, 2014 Permalink | Reply
    Tags: , Fermilab, FNAL LBNF,   

    From FNAL- “Director’s Corner: Toward a strong, international neutrino collaboration” 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Tuesday, Dec. 9, 2014
    nl
    Fermilab Director Nigel Lockyer

    Fermilab has always been an international laboratory. With the proposed Long-Baseline Neutrino Facility based here at Fermilab, we’re about to enter a bold new era of global cooperation.

    This Friday, Dec. 12, Fermilab will host the second of two open meetings about LBNF. These meetings are a big step toward forming a strong collaboration with partners across the globe, with the goal of building the best neutrino experiment of its kind in the world.

    Last Friday, the first of these meetings took place at CERN. We introduced CERN’s Director of Research Sergio Bertolucci as the interim chair of the International Institutional Board of the new collaboration, and we explained the organizational structure that we plan to put in place, with input and participation from international funding agencies. Rob Roser walked us through the current draft of the letter of intent for the experiment. Meeting participants discussed how to optimize the design of the experiment and started to discuss the scientific strategy. Many aspects of the experiment are still under discussion, and we are actively seeking input from all interested scientists. The goal is to finalize the letter of intent by Dec. 21 and submit it for review by the Fermilab Physics Advisory Committee, which will meet in January.

    This Friday it’s our turn to host the second meeting, which has an agenda identical to the first one. It will be held in One West from 10 a.m. to 3 p.m. All interested scientists, from graduate students to engineers to principal investigators, are encouraged to attend. Please register for the meeting so that we know approximately how many people to expect.

    The meeting will be a chance to voice your questions and ideas. There will be a panel discussion with an extended Q&A. An agenda with call-in information can be found online.

    The next major event in forming a new collaboration for long-baseline neutrino physics will be the PAC meeting on Jan. 15 and 16 at Fermilab. Sergio Bertolucci will present the letter of intent to the PAC on behalf of the nascent collaboration.

    See the full article here.

    Please help promote STEM in your local schools.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics.

     
  • richardmitnick 6:49 pm on December 7, 2014 Permalink | Reply
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    From htxt.africa via FNAL: “Meet Claire Lee, a South African ATLAS physicist at CERN” 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    htxtdotafrica

    Anyone with even a passing interest in the sciences must have wondered what it’s like to work at the European Organisation for Nuclear Research, better known as CERN. Based in Switzerland, it’s one of the world’s largest and most respected centres for scientific research, birthplace of the worldwide web and home of the gigantic underground particle accelerator, the Large Hadron Collider (LHC).

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    What wonders await those who join its ranks? What marvels must there be in the midst of such concentrated brain power?

    Since our chances of landing a job at CERN are probably limited to exciting opportunities in catering or sanitation, we figured it’s better to ask someone who does know. Someone like South African phyicist Claire Lee, who works right on ATLAS – one of the two elements of the LHC project that confirmed the existence of the Higgs boson in 2012.

    CERN ATLAS New
    ATLAS

    Lee has been involved with CERN since 2008 and has lived at the Swiss institute with her family for the past three and a half years. htxt.africa’s Tiana Cline sat down with Lee for a chat about all-things CERN, astrophysics and the elusive Higgs.

    How did you get interested in physics?

    Haha, this is a funny story. I’ve always loved science as long as I can remember (when I was very little I wanted to be an astronaut or an archaeologist), and have been fascinated with space since I could walk. But it really started in high school when I read the book Sphere by Michael Crichton. There was a character in the book who was an astrophysicist and I remember thinking to myself “Astrophysicist has to be about the coolest job title in the world, I want to be that!” So I set off to university with astrophysics as my final goal; however the astro-related projects that I ended up doing just didn’t seem to ever grab my interest. It was only in 2004, when for my Honours project I followed a basic version of what a friend was doing for his PhD in high energy nuclear physics, that I really started feeling the excitement.

    ac
    ATLAS Collaboration

    So science and physics were always a passion?

    In physics, High Energy Physics (HEP) is definitely my favourite, with a focus on Higgs and Beyond the Standard Model (BSM) physics. Our current theoretical knowledge is culminated in what is known as the Standard Model of Particle Physics, though we know that the theory is not complete (it doesn’t explain dark matter or dark energy, for example, nor the neutrino masses, and we have no idea how to incorporate gravity into the mix). So clearly there is lots of work still to do that will keep us hopefully busy with discoveries (or at least progress) for a while.

    In other fields, I do enjoy following the latest results in cosmology (such as the Planck vs BICEP2 saga, and AMS) and in particular where the fields of cosmology/astrophysics and particle physics overlap.

    And on a more personal note, neuroscience and the way the brain learns is fascinating too.

    Before jetting off to CERN, you studied in South Africa at both Wits and the University of Johannesburg as well as in Taiwan…

    I started off doing a BSc degree at Wits, I took Physics, Math, Applied Math and Chemistry in first year (2001). I hated Chemistry, so I dropped that first, took a second year Astronomy course, and ended up with Physics & Applied Math in 3rd year. I then did an Honours in Physics which was possibly one of the most fun years I’ve had in my life (we were a great class – 2004). At the end of that year I travelled to Virginia, USA for three weeks to work on an experiment at Jefferson Lab which became the subject of my MSc. I finally finished the MSc in 2009, also through Wits, and then moved to UJ where my supervisor had moved.

    As of 2007 South Africa wasn’t yet involved in the ATLAS experiment (though we had been working on ALICE, as well as ISOLDE and some of the smaller NA experiments for quite some time). But the annual South African Institute of Physics (SAIP) Conference we met Ketevi Assamagan, a US citizen originally from Togo, who was working at Brookhaven National Laboratory (BNL) on ATLAS. He had been invited to South Africa to speak at the conference – I think by Zeblon Vilakazi, member of the ALICE collaboration and (I think) director of iThemba LABS at the time. A group of us, especially my supervisor Prof Simon Connell and myself, were particularly interested in the type of physics ATLAS was doing, and a year later (2008) we flew to CERN to attend one of the ATLAS collaboration internal conferences, and meet with some of the heads of the experiment to discuss our involvement.

    The end of 2008 also saw the launch of the South Africa – CERN Programme which brought all the groups working on the various experiments together under one consortium.

    “Our current theoretical knowledge is culminated in what is known as the Standard Model of Particle Physics, though we know that the theory is not complete…” — Claire Lee, South African particle physicist

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    The Standard Model of elementary particles, with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    ATLAS is an expensive experiment to keep running, and as such requires a financial commitment from its member institutions. There are yearly fees based on personnel (students are free), as well as a joining fee which equates to about R1M. The agreement was that we would have two years to account for the joining fee (from the DST), and BNL would cover our yearly fees in the meantime. In 2009 Prof Connell was at UJ, and Wits hired an ATLAS physicist Prof Trevor Vickey. Together they got their respective universities to commit to R250k each of the ATLAS joining fee, and the government to the other R500k, and in July 2010 the two universities were officially voted into the ATLAS collaboration as part of a single South African institute. (Since then UCT and then UKZN have joined the cluster.)

    I also lectured at UJ (first year calculus-based physics, extended programme) for two years from 2009-2011, and my son was born in May 2010.

    Thanks to popular TV shows like the Big Bang Theory, places like CERN and the idea of being a physicist has been somewhat romanticised. What is life at CERN really like?

    My best friend came to visit and described it as “Just like a huge university, with no undergrads” and that’s a pretty good explanation! There are so many facets to it, but for the most part you wouldn’t say you were at one of the world’s top scientific institutions just by walking around: most of the buildings were built to pretty utilitarian standards. We joke that all expense was spared above ground here, but it is part true as the most important part are the accelerators and detectors below ground. CERN itself employs less than 3 000 people – some scientists, but mostly staff in management, HR and engineering. There are about 10 000 people working on CERN projects in total, but most are attached to their own University or institute, and definitely not all at CERN at once!

    CERN has a large turnover of people, one of its missions is to train people in a worldwide environment and then let them take their experience back home, and so there is always a flux of especially young people moving in and out of the area (it gives you a whole new perspective on the concept of friends). A lot of people will move to CERN for a year or so of their PhD, especially at the start, to completely immerse themselves in the physics, and then move back to their home institute for the rest of their degree, just making occasional trips to CERN.

    It’s easy to just focus completely on the physics aspect, but of course there is a large social side too, and CERN has a number of clubs and societies for just about anything you can think of (sailing, dancing, karate, LGBT and so on). CERN also does a great deal of outreach – I have hosted a number of underground visits to ATLAS, and virtual visits to the control room, competed in, compared and judged the FameLab competition, as well as co-organised two standup comedy evenings!

    I think one of the things I really like about the CERN ethos in general is that it doesn’t matter who you are, what matters is what you are good at. And CERN has become pretty good at using the talents of their personnel to their best advantage (as long as you’re happy for them to be used, of course!).

    What has been the most interesting part about being at CERN since you moved to Switzerland at the end of June 2011?

    There have been so many interesting things – being on shift and looking after a part of the detector during the 2012 physics run was great, and the Higgs boson discovery and announcement was a huge highlight! But also the people – everyone I meet is pretty great in one way or another, and I have made some very close friends who are all amazing at what they do as well as in their extracurricular activities. It’s wonderful to be surrounded by so many exceptional people.

    Also, on a personal note, watching my son grow up in the French-speaking world has been amazing. He was just over a year old when we moved over, and at one and a half he started going to a French creche (my husband looked after him full-time for those first five months while I worked). He now speaks fluent French (WAY better than either of us) as well as English.

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    Lee hosting a “virtual visit” with Algeria from the ATLAS control room.

    A silly question – but what do you actually do on a day-to-day basis?

    My standard day is usually comprised of some mix of coding and attending meetings (either in person or remotely via Skype), interspersed with coffees and lunch. There are many different types of work one can do, since I am mostly on analysis this means coding, in C++ or Python, for example to select a particular subset of events that I am interested in from the full set of data. This usually takes a couple of iterations, where we slim down the dataset at each step and calculate extra quantities we may want to use for our selections.

    The amount of data we have is huge – petabytes of data per year stored around the world at various high performance computing centres and clusters. It’s impossible to have anything but the smallest subset available locally – hence the iterations – and so we use the LHC Computing Grid (a specialised worldwide computer network) to send our analysis code to where the data is, and the code runs at these different clusters worldwide (most often in a number of different places, for different datasets and depending on which clusters are the least busy at the time). At the ultimate or penultimate step our personalised datasets are usually small enough to put somewhere local (either on a laptop or university cluster) from which we can make nice-looking plots etc.

    Various meetings happen all day every day on ATLAS, though of course you only attend the ones relevant to the work you are doing as it would be impossible otherwise! Whether it’s an analysis- or performance-related meeting (analysis is, eg, a particular physics analysis, such as a Higgs measurement, while performance studies relate to the measurement and calibration of the physics objects – like electrons – that are used in the analyses) people will present their most recent work, and usually there will be some discussion on how to move forward.

    a
    View of the ATLAS cavern side A beginning of February 2008, before the lowering of the Muon Small Wheels.

    And on the ATLAS Experiment?

    The ATLAS experiment is one of the four large experiments at the LHC. It is also the biggest of the four detectors (in volume) and like CMS, is a general-purpose detector, designed to detect all particles from the high energy proton-proton collisions. This allows ATLAS to cover many different aspects of physics, from measurements of the Higgs boson to searches for new physics. The detector itself is built like a giant three-dimensional puzzle of different detector components, with each part measuring a different aspect of the final-state particles from the collisions as they move through the detector.

    To be able to do any analysis, after the data has been recorded the events have to be reconstructed, meaning that the signals from the different parts of the detector are combined and fitted into objects such as electrons, muons, jets etc. Analyses can then select events based on the objects they have in them – a Higgs boson decaying to four leptons, for example, would then select events containing electrons and/or muons.

    Other quantities based on these objects are also calculated, such as the missing transverse momentum, which is the vector sum of the energies of all the particles in the event, measured by the calorimeters (and comes about due to conservation of momentum). This is important for events where we have particles that we do not detect, such as neutrinos, and so the only way we know they are there is by noticing an imbalance in the total momentum (the neutrino would then be going in the other direction). A very large amount of missing momentum, by the way, could also be a signal for a supersymmetric particle, so this quantity is used in a number of analyses.

    I’ve done various things – I worked as an online expert for one of the ATLAS calorimeters, for example, making sure that it was running properly and able to take good data while the collisions were happening. This sometimes involved being called in the middle of the night to solve problems!

    But one of my main tasks, and what my thesis is on, has been developing a new and complimentary method of measuring the missing transverse momentum, only this time we use particle track momenta rather than calorimeter energy measurements. This method has proven to be very useful, especially when combining the result with the “traditional” measurement from the calorimeter, and is used in various Higgs analyses to help separate signal from background.

    We’ve heard that there are over 3 000 physicists working on ATLAS. Who are the other African scientists working at the institute? It must be interesting working with such a diverse group of people.

    Ketevi Assamagan (who is now a co-supervisor of mine), for example, was the first ATLAS physicist I ever met. My other supervisor (Rachid Mazini) works for Taiwan but he is originally from Morocco. And of course although the groups have grown in the past few years, the High Energy Physics community in South Africa is pretty small, and we all fall under the SA-CERN programme, so we know each other quite well.

    There are over 100 different nationalities represented on ATLAS, so you become quite culturally-aware, especially when it comes to being sensitive of others’ commitments around things like Thanksgiving, Ramadan, Christmas, etc, as well as personal issues like kids. I’ve found that people are in general pretty tolerant, and as long as your work is coming along well you are pretty free to work as you see fit.

    swh
    Several hundred of the 1 700 scientists contributing to the LHC accelerator and experiments gathered in CERN’s building 40.

    Back to South Africa – are you positive about the state of science/physics education here?

    Yes and no. I think universities are doing a good job, mostly, we do have some top quality researchers here in South Africa and are able to place well on the international scale. On the other hand, the quality of the schooling is going down terribly, and some of the students gaining university entrance nowadays and qualifying for these courses know extremely little. This only puts pressure on the universities, increasing lecturers’ loads, which is unfortunate.

    Science is tough generally, and the sort of high-pressure environment that ATLAS is even tougher, so you need to have some internal reason to continue doing what you do. Second, making sure you have really supportive people around you also is important, people who encourage you to succeed and are there for you when you need them. And finally, it’s about making contacts; attending meetings (in person if you can) and talking to people and presenting your work regularly, as well as more “fun” stuff like outreach, all helps to get people to know who you are and what you can do.

    See the full article here.

    Please help promote STEM in your local schools.

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    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics.

     
  • richardmitnick 2:39 pm on December 5, 2014 Permalink | Reply
    Tags: , , Fermilab,   

    From FNAL- “Frontier Science Result: CMS Precisely measuring nothing” 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Friday, Dec. 5, 2014

    FNAL Don Lincoln
    Don Lincoln

    The CMS detector is a technical tour de force. It can simultaneously measure the passage of electrons, pions, muons, photons and all manner of particles, both short-lived and long-lived.

    CERN CMS New
    CMS at The LHC at CERN

    However, there are some particles that simply don’t interact very much with matter. These include neutrinos and some hypothetical long-lived and weakly interacting particles that may appear in collisions that probe supersymmetry, extra dimensions of space and dark matter. The CMS detector simply doesn’t see those kinds of particles.

    m
    Collisions like these indicate the existence of invisible particles. The blob of color in the upper left hand corner shows where particles were knocked out of the collision to deposit energy in the detector. The fact that we see no balancing energy in the lower right hand corner means that an invisible particle has escaped the detector. As the number of simultaneous collisions in the LHC increases, it will become increasingly difficult to study this kind of physics.

    Supersymmetry standard model
    Standard Model of Supersymmetry

    That sounds like a terrible oversight, but the reality is more comforting. We can use physical principles of the kind taught in high school physics classes to identify collisions in which these particles are made. Essentially, we see them by not seeing them.

    In the first semester of physics, we learn about a quantity called momentum and how it is conserved, which means it doesn’t change. In the classical world, momentum is determined by multiplying an object’s mass and velocity. In the world of relativity and particles, the definition is a bit different, but the basic idea is the same and the principle that momentum is conserved still applies.

    Prior to a collision, particles travel exclusively along the beam direction. This means that before the beam particles collide, there is no momentum perpendicular to the beams, or what scientists call transverse momentum. According to the laws of momentum conservation, there should be zero net transverse momentum after the collision as well. If we sum the transverse momentum of all particles coming out of the collision, that’s what we find.

    However, when there are undetectable particles, the measured transverse momentum is unbalanced. Scientists call the unobserved transverse momentum missing transverse energy, or MET. MET is a clear signature of the existence of one or more invisible particles. Accordingly, it is important to measure carefully the transverse momentum of all observable particles.

    Particle experiments have been employing this technique for decades, but few experiments have operated in the challenging collision environment that exists at the LHC. Any time the beams pass through one another, typically dozens of collisions between beam particles occur. Most often, one of those collisions involve some “interesting” process, while the others usually involve much lower-energy collisions. However, those low-energy collisions still spray particles throughout the detector. The existence of these extra particles confuse the measurement of MET and make it tricky to know the exact momentum of the invisible particles.

    CMS scientists have worked long and hard to figure out how to mitigate these effects and recently submitted for publication a paper describing their algorithms. With the impending resumption of operations of the LHC in the spring of 2015 (which could involve as many as 200 simultaneous collisions), researchers will continually revise and improve their techniques.

    See the full article here.

    Please help promote STEM in your local schools.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics.

     
  • richardmitnick 12:04 pm on December 4, 2014 Permalink | Reply
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    From FNAL- “Frontier Science Result: CDF Wading through the swamp to measure top quark mass” 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Thursday, Dec. 4, 2014
    edited by Andy Beretvas

    Even after the discovery of the Higgs boson, the top quark is still a focus of attention because of its peculiar position of being the heaviest quark in the Standard Model and for its possible role in physics beyond the Standard Model.

    sm
    The Standard Model of elementary particles, with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    If the Standard Model is correct, the stability of the vacuum strongly depends on the mass of the Higgs boson and the top quark mass. In this context, scientists favor the scenario that the universe is in a metastable state. A precision measurement of the top quark mass helps to better determine the relative stability of that state in this scenario.

    At the Tevatron, top quarks were produced, mostly in pairs, only once in about 10 billion collisions. They decayed right away into a W boson and a b quark. In the most abundant and yet most challenging scenario, the final state contains six collimated sprays of particles, called jets, two of which likely originated from the b quarks, with peculiar, identifiable characteristics (allowing them to be “b-tagged”). This decay mode is usually called the all-hadronic channel, for which the signal is swamped by a background associated to the production of uninteresting multijet events, which were about a factor of 1,000 more abundant than the signal events.

    FNAL Tevatron
    Tevatron

    This new analysis uses the full CDF Run II data set.
The set contains nearly twice the number of top quark pairs as seen in our previous measurement. The analysis uses an improved simulation and relies on there being at least one b-tagged jet. An important part of the analysis is to minimize the uncertainty in our measurement of jet scale energies. Exploiting the expected behavior of top-antitop signal events, the huge background can be tamed through finely tuned requirements, yielding about 4,000 events, where about one event out of three is expected from the signal. The all-hadronic final state can then be fully reconstructed using the energies of the six jets, and the mass of the top quark can be derived comparing the data to simulations produced for different input values of the top quark mass (see the [below] figure).

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    The black dots plot the distribution of the reconstructed top mass for events containing one or more b-tags. The distribution is compared to the expected yield for background and signal events, normalized to the best fit.

    FNAL CDF
    CDF

    This procedure yields a value of 175.1 ± 1.2 (stat) ± 1.6 (sys) GeV/c2 for the top quark mass, with a 1 percent relative precision. This measurement complements the results obtained by CDF in other channels. Our measurement is consistent with the current world average (which includes our previous measurement in the all-hadronic channel), obtained from measurements by ATLAS, CDF, CMS and DZero. The top quark mass world average is 173.3 ± 0.8 GeV/c2.

    CERN ATLAS New
    ATLAS

    CERN CMS New
    CMS

    FNAL DZero
    DZero

    See the full article here.

    Please help promote STEM in your local schools.

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    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics.

     
  • richardmitnick 8:10 pm on December 1, 2014 Permalink | Reply
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    From Scientific American- Don Lincoln of Fermilab “U.S. Particle Physics Program Aims for the Future” 

    Scientific American

    Scientific American

    November 25, 2014

    FNAL Don Lincoln
    Dr. Don Lincoln

    n the last few years, stories have abounded in the press of the successes of the Large Hadron Collider, most notably the discovery of the Higgs boson. This has led some to speculate that European research is ascendant while U.S. research is falling behind. While there is no argument that U.S. particle physics budgets have shrunk over the past decade, it is also inarguable that America is still huge player in this fascinating research sector, collaborating on projects in Europe and Asia while pursuing a strong domestic program as well.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    To properly appreciate the breadth of the U.S.’s contribution to particle physics research, one must distinguish between the international program and the domestic one. The international program is currently (and appropriately) focused mostly on the LHC. The ring-shaped collider is, without a doubt, an amazing piece of equipment. It is 17 miles around, took a quarter century to plan and build, cost about $10 billion, and requires about 10,000 scientists to operate and study the data it generates. Four distinct experiments (ALICE, ATLAS, CMS and LHCb) were built to use the LHC to investigate some of mankind’s oldest scientific questions.

    CERN ALICE New
    ALICE

    CERN ATLAS New
    ATLAS

    CERN CMS New
    CMS

    CERN LHCb New
    LHCb

    Physicists employed by U.S. universities and national laboratories comprise about a third of the LHC experimental program, making the U.S. the single largest country involved in the project. Although the CERN laboratory itself employs more LHC scientists than any other single institution, America’s Fermilab and Brookhaven National Laboratory are uncontested seconds for CMS and ATLAS, respectively. American physicists lead many analysis efforts and the CMS collaboration even elected Professor Joe Incandela of the University of California, Santa Barbara to be the group leader.

    fnal
    Fermilab’s Main Ring and Main Injector as seen from the air. (Credit: Reidar Hahn/Fermilab)

    While there is no denying the attractiveness of the LHC as a scientific opportunity, U.S. scientists also pursue an active and vibrant U.S. domestic program. Fermilab serves as the hub for the American particle physics community and the laboratory’s accelerators, both present and future, are helping scientists blaze new trails into the fascinating subatomic world.

    Because the LHC is firmly ensconced as the highest energy facility in the world for the foreseeable future, Fermilab is focusing on a different technique to delve into the fundamental rules of the universe. By choosing to concentrate on making the highest intensity particle beams ever achieved, the U.S.’s domestic program is able to investigate some of the rarest phenomena ever imagined at energy scales that far exceed those accessible at the LHC. High energy means that individual beam particles are moving at unprecedented speeds, while high intensity means many particles focused on a tiny area, much like a magnifying lens can focus light. When many particles are brought into tight proximity, there is a small chance that a quantum mechanical fluctuation will allow an extremely unlikely and ultra-high energy interaction to occur.

    It’s easy to explain to people why building a higher energy facility is valuable, but understanding why higher intensity beams is a leading research strategy is a little more difficult and requires two insights. The first and simpler insight is to realize that in particle physics, we look for rare collisions between beams of particles. The reason we look for rare ones is that the common ones have been studied already.

    bnl
    The central campus of Brookhaven National Laboratory. The National Synchrotron Light Source II, under construction at the time of this photo, is at bottom, right. The 3.8-kilometer circumference ring of the Relativistic Heavy Ion Collider can be seen in the distance at the top of the frame. (Credit: Brookhaven National Laboratory)

    To observe the rarest collisions, one must simply make a lot of collisions and wait. It’s similar to trying to win the lottery. If you buy one ticket, you are unlikely to succeed, but if you buy many tickets there is a much higher chance that you have bought a winner.

    The more subtle insight hinges on the principles of physics, specifically quantum mechanics. While it is a firm rule of classical physics that energy is conserved, this rule is not so rigidly observed in the quantum realm. According to the tenets of the Heisenberg Uncertainty Principle, energy can simply appear, as long as it disappears quickly enough. Further, the larger the temporary energy imbalance, the shorter the duration. Thus, because they persist for so short a time, the large energy imbalances are very rare. And, as I have noted above, to study very rare processes, one must employ very intense beams.

    Using the current Fermilab accelerator complex, physicists are studying the interactions of neutrinos with matter. Neutrinos only experience the weak nuclear force and can pass through a lot of matter without interacting. To give a sense of scale, the sun constantly emits neutrinos. If we were determined to stop half of them, we’d need a wall composed of solid lead that is five light years thick! Given this reluctance to interact, the only way to ensure enough neutrino interactions to study is to generate incredibly intense beams and analyze them with massive particle detectors.

    The Fermilab MINOS and NOvA experiments shoot unprecedentedly bright beams of neutrinos from Chicago to northern Minnesota to study an interesting phenomenon called neutrino oscillations. Neutrinos are unique in that they can change their identity, vaguely as if an electron could change into a proton and back. It is hoped that understanding this oscillatory behavior might explain why the universe is made solely of matter when we believe that matter and antimatter existed in equal quantities when the universe began.

    FNAL NOvA
    FNAL NOvA

    mu
    The muon g-2 storage ring arrives at Fermilab, near Chicago, in July 2013 after a cross-country trip from Brookhavn National Laboratory on Long Island, New York. (Credit: Reidar Hahn/Fermilab)

    A second bright star in the constellation of U.S. particle physics research is the use of Fermilab’s accelerator complex to study muons, the heavy cousins of electrons. Scientists of the Muon g-2 experiment will measure the magnetic moment of muons. Earlier measurements at the Brookhaven National Laboratory were very precise – with eight digits of precision. However, there is a tantalizing tension between data and theoretical predictions. While both measurement and prediction are exquisitely precise, the two numbers disagree slightly. This disagreement is small, but is about three and a half times larger than the combined experimental and theoretical uncertainty. This discrepancy could signify the onset of new physics, which could involve supersymmetry, muon substructure or something entirely unexpected. Because Fermilab can generate more intense beams of muons than Brookhaven, the g-2 apparatus was moved from Long Island, New York to Chicago to investigate this question more thoroughly.

    Supersymmetry standard model
    Standard Model of Supersymmetry

    Yet another interesting question that has been investigated relates to unconventional muon decays. Most muons decay into electrons and two neutrinos, however there are reasons to suspect that perhaps muons might decay into electrons without neutrinos. The Mu2e experiment at Fermilab is scheduled to start recording data in a couple of years and this experiment will be sensitive to energy scales far higher than the LHC can achieve. Since neutrinos transform into other types of neutrinos and quarks can change into other quarks, physicists think that the transition of muons into electrons might be possible. Because this decay is expected to be very rare (if it exists at all), this is another reason to make high intensity muon beams.

    A multi-year study of the pressing physics questions by the entire U.S. particle physics community resulted in a firm recommendation to upgrade the Fermilab accelerator complex to further increase the amount of beam it can supply. Thus, the long term plan for the Fermilab laboratory is to increase the intensity of its neutrino beams by at least 50 percent and shoot these beams off to a detector to be located in South Dakota. Because neutrinos change their identity (i.e. oscillate) in flight, having detectors at different distances from Fermilab gives a complementary view of neutrino oscillations and it will shed more light on the phenomenon.

    FNAL LBNE

    But the U.S. community hasn’t forgotten the energy frontier. Eventually, there will be an accelerator that replaces the LHC as the energy leader. It will be a long time before any decisions are made on where that facility might be located (or even what kinds of beams will be needed: protons or electrons). But, to be prepared, several institutions across the U.S. are expanding their accelerator development programs. Whether the future facility is located in the U.S., Europe or Asia, U.S. accelerator scientists will be heavily engaged in developing the required technology.

    Even with tight budgets, the American particle physics community has continued to have a huge impact in humankind’s investigations of some of the oldest scientific questions, and continued support is key to maintaining this leading role.

    See the full article here.

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    Scientific American, the oldest continuously published magazine in the U.S., has been bringing its readers unique insights about developments in science and technology for more than 160 years.

     
  • richardmitnick 3:32 pm on November 26, 2014 Permalink | Reply
    Tags: , , Fermilab,   

    From LC Newsline: “Vertical wonder” 

    Linear Collider Collaboration header
    Linear Collider Collaboration

    26 November 2014
    Joykrit Mitra

    In 2006, Fermilab’s Particle Physics Division teamed up with MIT’s Lincoln Labs to start work on the first iteration of a new kind chip for the proposed International Linear Collider’s vertex detector. A new way to slim down chips was emerging in the semiconductor industry, one that could potentially make it easier to measure the properties of incoming particles. Eight years and several iterations later, the chip is now close to being complete, and the ILC vertex detector is another step closer to being an engineering reality.

    set
    Fermilab’s vertically stacked chips bonded onto sensor wafers. Photo Credit: Reidar Hahn

    In old-fashioned circuit boards, components are arranged side by side on a flat surface. An electrical signal has to travel a long distance to reach the processor, and generates excess electrical noise in the process, reducing the clarity of the output. To solve this problem, the semiconductor industry started vertically stacking wafer-like silicon layers — each thinner than a human hair—and bonding them together chemically. The stacked arrangement is called a 3-D integrated circuit.

    A 3-D arrangement is especially useful for the ILC vertex detector, where the chip and its associated sensor need to be as thin as practicable so as not to disrupt the path of the incoming particles too much and interfere with their properties. Furthermore, the circuitry needs to make do with limited power and still manage to capture a particle’s position, time stamp of arrival and charge at a good resolution.

    Lincoln Labs and Fermilab collaborated to build this kind of a chip. The first iteration, VIP I – or vertically integrated pixel chip – was assembled in Lincoln Labs with three layers stacked together. The two labs went on to design a successor, VIP II-a.

    “When we originally started working on it, our goals were pretty ambitious,” said Ron Lipton of Fermilab’s Particle Physics Division who worked on detector R&D for the ILC and worked with the engineers designing the chip. “But it was clear that if you wanted to really make progress, you had to have commercial technology.”

    At this stage Tezzaron, based in Naperville, Illinois, and Ziptronix of Morrisville, North Carolina, were brought in to help develop VIP II-b, in which each wafer had a 192-by-192-pixel arrangement and greater resolution than its predecessors.

    Tezzaron had created a working 3-D prototype in 2004 connecting two wafers with tungsten contacts embedded in the silicon, and Ziptronix had found a way to get rid of the 50-micron- thick solder bumps being used industrially to connect each pixel on a chip surface to the sensor. Ziptronix engineers had replaced the bumps with metal cylinders only 5 microns in diameter and 1 micron high embedded in a glass insulator, decreasing the distance between pixel and sensor by a factor greater than 10. These advances were integrated into the latest iteration of the VIP.

    tm
    Tungsten mask of the Fermilab logo rendered using the VIP II-b chip. Photo Credit: Ron Lipton

    So far VIP II-b has been tested qualitatively. A mask of the Fermilab logo made of tungsten, 400 microns thick, was pressed against the chip and bombarded with a radioactive source, and the chip was able to reproduce a readout of the pattern at a high resolution with relatively low noise. The result showcases the device’s abilities and serves as testament that the basic circuitry works.

    Next up is detecting an actual particle beam. A collaboration between Argonne National Laboratory, Brown University and Fermilab to optimize the chip quantitatively for such a setup is under way.

    “We have all of the pieces necessary to build a functional prototype for the vertex detector,” Lipton said. “The next step will depend on how the ILC project proceeds.”

    See the full article here.

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    The Linear Collider Collaboration is an organisation that brings the two most likely candidates, the Compact Linear Collider Study (CLIC) and the International Liner Collider (ILC), together under one roof. Headed by former LHC Project Manager Lyn Evans, it strives to coordinate the research and development work that is being done for accelerators and detectors around the world and to take the project linear collider to the next step: a decision that it will be built, and where.

    Some 2000 scientists – particle physicists, accelerator physicists, engineers – are involved in the ILC or in CLIC, and often in both projects. They work on state-of-the-art detector technologies, new acceleration techniques, the civil engineering aspect of building a straight tunnel of at least 30 kilometres in length, a reliable cost estimate and many more aspects that projects of this scale require. The Linear Collider Collaboration ensures that synergies between the two friendly competitors are used to the maximum.

    Linear Collider Colaboration Banner

     
  • richardmitnick 3:18 pm on November 26, 2014 Permalink | Reply
    Tags: , Fermilab,   

    From FNAL: “From the Scientific Computing Division – Strengthening the computing foundation of Fermilab” 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Wednesday, Nov. 26, 2014

    fn
    Panagiotis Spentzouris, head of the Scientific Computing Division, wrote this column.

    Scientific computing, through the process of numerical modeling and simulation, complements theory and experiment as a way to obtain scientific knowledge. But computing is more than the third leg of the discovery stool. Scientific computing also supports and enables the other two through data collection, reconstruction and analytics. It has always been an essential part of the Fermilab physics program.

    FNAL Scientific Computing

    Every time I see a picture of an event from the Large Hadron Collider’s CMS experiment or, in more recent times, a NOvA event, I think of our Scientific Computing Division’s contributions. NOvA hit the ground running, collecting data with an SCD-designed and -commissioned data acquisition system, processing data with SCD-developed software, and running on computing resources supported by SCD workflow management services and operations. SCD also develops and supports tools and applications for detector and accelerator simulation and physics generation.

    CERN CMS New
    CMS in the LHC at CERN

    FNAL NOvA
    FNAL NOvA

    All in all, SCD has been exceedingly successful in delivering world-class computing services, operations and software engineering support to Fermilab-based experiments, CMS and the high-energy physics community at large, working closely with our users. However, as Fermilab moves forward with the P5 plan, we face many scientific computing challenges.

    First, we must provide the same high level of support to various experiments with different timelines and priorities. In addition, as computing architectures evolve, we must change the paradigms for how we construct our algorithms, write our codes and organize our analysis flows. Also, while new technologies, such as more accessible cloud computing, provide attractive possibilities for deploying computing resources, they require us to develop new services for on-demand reliable resource allocation.

    In order to meet these challenges and continue to serve the needs of our user community, we have reorganized SCD and aligned our activities across three major areas. One is development, integration and research, in which we create the products that run on our facilities. The second is facilities, where we operate the services that run these products. The third is science operations and workflows, through which we tailor applications of the facility services to our experiments and projects and assist with operations.

    Of course, no organization can be successful without its people. In the nearly three months since I became division head, my interactions with all parts of SCD have reinforced this belief. SCD members have unique and diverse skills in a variety of professions, including scientists, engineers, software architects and developers, and experts in using and operating high-performance and high-throughput computing systems.

    It is very exciting to be at Fermilab now. The Fermilab neutrino program is on its way with more experiments to come online; CMS is about to restart taking data; the muon program will start soon; and our accelerator complex upgrades are well under way. We in SCD are looking forward to working with the rest of the laboratory to make this program a great success. Happy Thanksgiving!

    FNAL Muon G-2 Magnet
    The Muon G2 magnet

    See the full article here.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics.

     
  • richardmitnick 2:46 pm on November 26, 2014 Permalink | Reply
    Tags: , , Fermilab, , Scintillators   

    From FNAL: “Scintillator extruded at Fermilab detects particles around the globe” 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Wednesday, Nov. 26, 2014
    Troy Rummler

    Small, clear pellets of polystyrene can do a lot. They can help measure cosmic muons at the Pierre Auger Observatory, search for CP violation at KEK in Japan or observe neutrino oscillation at Fermilab. But in order to do any of these they have to go through Lab 5, located in the Fermilab Village, where the Scintillation Detector Development Group, in collaboration with the Northern Illinois Center for Accelerator and Detector Design (NICADD), manufactures the exclusive source of extruded plastic scintillator.

    scin
    The plastic scintillator extrusion line, shown here, produces detector material for export to experiments around the world. Photo: Reidar Hahn

    Like vinyl siding on a house, long thin blocks of plastic scintillator cover the surfaces of certain particle detectors. The plastic absorbs energy from collisions and releases it as measurable flashes of light. Fermilab’s Alan Bross and Anna Pla-Dalmau first partnered with local vendors to develop the concept and produce cost-effective scintillator material for the MINOS neutrino oscillation experiment. Later, with NIU’s Gerald Blazey, they built the in-house facility that has now exported high-quality extruded scintillator to experiments worldwide.

    “It was clear that extruded scintillator would have a big impact on large neutrino detectors,” Bross said, “but its widespread application was not foreseen.”

    Industrially manufactured polystyrene scintillators can be costly — requiring a labor-intensive process of casting purified materials individually in molds that have to be cleaned constantly. Producing the number of pieces needed for large-scale projects such as MINOS through casting would have been prohibitively expensive.

    Extrusion, in contrast, presses melted plastic pellets through a die to create a continuous noodle of scintillator (typically about four centimeters wide by two centimeters tall) at a much lower cost. The first step in the production line mixes into the melted plastic two additives that enhance polystyrene’s natural scintillating property. As the material reaches the die, it receives a white, highly reflective coating that holds in scintillation light. Two cold water tanks respectively bathe and shower the scintillator strip before it is cool enough to handle. A puller controls its speed, and a robotic saw finally cuts it to length. The final product contains either a groove or a hole meant for a wavelength-shifting fiber that captures the scintillation light and sends the signal to electronics in the most useful form possible.

    Bross had been working on various aspects of the scintillator cost problem since 1989, and he and Pla-Dalmau successfully extruded experiment-quality plastic scintillator with their vendors just in time to make MINOS a reality. In 2003, NICADD purchased and located at Lab 5 many of the machines needed to form an in-house production line.

    “The investment made by Blazey and NICADD opened extruded scintillators to numerous experiments,” Pla-Dalmau said. “Without this contribution from NIU, who knows if this equipment would have ever been available to Fermilab and the rest of the physics community?”

    Blazey agreed that collaboration was an important part of the plastic scintillator development.

    “Together the two institutions had the capacity to build the resources necessary to develop state-of-the-art scintillator detector elements for numerous experiments inside and outside high-energy physics,” Blazey said. “The two institutions remain strong collaborators.”

    Between their other responsibilities at Fermilab, the SDD group continues to study ways to make their scintillator more efficient. One task ahead, according to Bross, is to work modern, glass wavelength-shifting fibers into their final product.

    “Incorporation of the fibers into the extrusions has always been a tedious part of the process,” he said. “We would like to change that.”

    See the full article here.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics.

     
  • richardmitnick 8:14 pm on November 24, 2014 Permalink | Reply
    Tags: , , , , , , Fermilab   

    From FNAL- Video: Dr Don Lincoln on Cosmic Inflation 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    In 1964, scientists discovered a faint radio hiss coming from the heavens and realized that the hiss wasn’t just noise. It was a message from eons ago; specifically the remnants of the primordial fireball, cooled to about 3 degrees above absolute zero. Subsequent research revealed that the radio hiss was the same in every direction. The temperature of the early universe was uniform to at better than a part in a hundred thousand.

    And this was weird. According to the prevailing theory, the two sides of the universe have never been in contact. So how could two places that had never been in contact be so similar? One possible explanation was proposed in 1979. Called inflation, the theory required that early in the history of the universe, the universe expanded faster than the speed of light. Confused? Watch this video as Fermilab’s Dr. Don Lincoln makes sense of this mind-bending idea.

    Watch, enjoy, learn.

    See the full article here.

    Please help promote STEM in your local schools.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics.

     
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