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  • richardmitnick 6:10 am on July 1, 2017 Permalink | Reply
    Tags: , FNAL CDF, , On May 30 our 700th paper was officially published in Phys. Rev. D, , ,   

    From FNAL: “CDF publishes 700 papers” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

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

    June 30, 2017
    David Toback

    Scientist David Toback, professor at Texas A&M University and the Mitchell Institute for Fundamental Physics and Astronomy, is co-spokesperson of the CDF experiment.

    The year 2017 is full of important Fermilab milestones. Fermilab’s 50th anniversary. The 25th anniversary of the lab’s first website. The 40th anniversary of the discovery of the bottom quark.

    FNAL/Tevatron CDF detector

    The Collider Detector at Fermilab, CDF, recently celebrated an important milestone — perhaps not as lofty or storied as the above anniversaries, but a proud moment nonetheless: On May 30, our 700th paper was officially published in Phys. Rev. D. The publication, which focuses on the production of D meson in the unique Tevatron environment, was led by an Italian student working with both American and Italian collaborators. It was a fitting way to ring in this milestone and encouraged us to reflect on the past 37 years of the collaboration.

    CDF was created as a United States-Italy-Japan collaboration. Today the pursuit of particle physics is unthinkable without global cooperation, but in 1980, when CDF started as a three-country endeavor, it was the primary vision of director Robert Wilson for the lab to go worldwide. CDF has included scientists from more than a dozen countries over the years, and would include more than 600 physicists at its peak.

    A storied history. With 700 publications, it is hard to choose only a few among so many highlights. Perhaps it is obvious to start with the 1995 co-discovery of the top quark. More than 20 years later, some CDF measurements, such as the measurement of the top mass, remain among the most sensitive in the world. Another important paper detailed the discovery of the quick-change behavior of the Bs meson, which switches between matter and antimatter 3 trillion times a second and was the first observation of CP violation in the b quark system. CDF’s measurement of the mass of the W boson is still the most precise on record. Perhaps equally important is that the production of these papers helped almost 640 individuals gain their Ph.D. using CDF data.

    A curious set of characters and stories. While most people know that current Fermilab Director Nigel Lockyer is a former CDF spokesperson, the current spokespersons have fun stories as well. A fun fact about CDF today is that its longevity has produced the remarkable occurrence that both spokespersons were Ph.D. students on the experiment. Giorgio Chiarelli, INFN-Pisa, was the second student to receive his Ph.D., and yours truly was the 159th. Equally amusing is that Chiarelli’s advisor, Giorgio Bellettini (who has been on CDF since the very beginning), was a two-time co-spokesperson himself and just handed off the baton to his student on June 1.

    Looking forward: With 37 years in the books, the road ahead is clearly shorter than the one in the past. However, even as the Large Hadron Collider goes strong, data collected from Tevatron collisions continues to add to the book on particle physics, and the experiment is still producing results. CDF looks forward to many important and competitive legacy measurements, including those of the top mass, the W mass, sin2θ­W, and the forward-backward asymmetry of top quark pairs. We retain our emphasis on getting the papers out.

    Congratulations CDF, and to members past and present, on your 700th paper and the many accomplishments you’ve logged along the way!

    1
    CDF collaboration. Photo: Cindy Arnold

    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. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

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  • richardmitnick 5:12 pm on June 29, 2017 Permalink | Reply
    Tags: , , , , , FNAL CDF, , HPSS -High Performance Storage System, , , , RACF - Resource Access Control Facility, Scientific Data and Computing Center   

    From BNL: “Brookhaven Lab’s Scientific Data and Computing Center Reaches 100 Petabytes of Recorded Data” 

    Brookhaven Lab

    Ariana Tantillo
    atantillo@bnl.gov

    Total reflects 17 years of experimental physics data collected by scientists to understand the fundamental nature of matter and the basic forces that shape our universe.

    1
    (Back row) Ognian Novakov, Christopher Pinkenburg, Jérôme Lauret, Eric Lançon, (front row) Tim Chou, David Yu, Guangwei Che, and Shigeki Misawa at Brookhaven Lab’s Scientific Data and Computing Center, which houses the Oracle StorageTek tape storage system where experimental data are recorded.

    Imagine storing approximately 1300 years’ worth of HDTV video, nearly six million movies, or the entire written works of humankind in all languages since the start of recorded history—twice over. Each of these quantities is equivalent to 100 petabytes of data: the amount of data now recorded by the Relativistic Heavy Ion Collider (RHIC) and ATLAS Computing Facility (RACF) Mass Storage Service, part of the Scientific Data and Computing Center (SDCC) at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory. One petabyte is defined as 10245 bytes, or 1,125,899,906,842,624 bytes, of data.

    “This is a major milestone for SDCC, as it reflects nearly two decades of scientific research for the RHIC nuclear physics and ATLAS particle physics experiments, including the contributions of thousands of scientists and engineers,” said Brookhaven Lab technology architect David Yu, who leads the SDCC’s Mass Storage Group.

    SDCC is at the core of a global computing network connecting more than 2,500 researchers around the world with data from the STAR and PHENIX experiments at RHIC—a DOE Office of Science User Facility at Brookhaven—and the ATLAS experiment at the Large Hadron Collider (LHC) in Europe.

    BNL/RHIC Star Detector

    BNL/RHIC PHENIX

    CERN/ATLAS detector

    In these particle collision experiments, scientists recreate conditions that existed just after the Big Bang, with the goal of understanding the fundamental forces of nature—gravitational, electromagnetic, strong nuclear, and weak nuclear—and the basic structure of matter, energy, space, and time.

    Big Data Revolution

    The RHIC and ATLAS experiments are part of the big data revolution.

    BNL RHIC Campus


    BNL/RHIC

    These experiments involve collecting extremely large datasets that reduce statistical uncertainty to make high-precision measurements and search for extremely rare processes and particles.

    For example, only one Higgs boson—an elementary particle whose energy field is thought to give mass to all the other elementary particles—is produced for every billion proton-proton collisions at the LHC.

    CERN CMS Higgs Event


    CERN/CMS Detector

    CERN ATLAS Higgs Event

    More, once produced, the Higgs boson almost immediately decays into other particles. So detecting the particle is a rare event, with around one trillion collisions required to detect a single instance. When scientists first discovered the Higgs boson at the LHC in 2012, they observed about 20 instances, recording and analyzing more than 300 trillion collisions to confirm the particle’s discovery.

    LHC

    CERN/LHC Map

    CERN LHC Tunnel

    CERN LHC particles

    At the end of 2016, the ATLAS collaboration released its first measurement of the mass of the W boson particle (another elementary particle that, together with the Z boson, is responsible for the weak nuclear force). This measurement, which is based on a sample of 15 million W boson candidates collected at LHC in 2011, has a relative precision of 240 parts per million (ppm)—a result that matches the best single-experiment measurement announced in 2007 by the Collider Detector at Fermilab collaboration, whose measurement is based on several years’ worth of collected data. A highly precise measurement is important because a deviation from the mass predicted by the Standard Model could point to new physics. More data samples are required to achieve the level of accuracy (80 ppm) that scientists need to significantly test this model.

    The volume of data collected by these experiments will grow significantly in the near future as new accelerator programs deliver higher-intensity beams. The LHC will be upgraded to increase its luminosity (rate of collisions) by a factor of 10. This High-Luminosity LHC, which should be operational by 2025, will provide a unique opportunity for particle physicists to look for new and unexpected phenomena within the exabytes (one exabyte equals 1000 petabytes) of data that will be collected.

    Data archiving is the first step in making available the results from such experiments. Thousands of physicists then need to calibrate and analyze the archived data and compare the data to simulations. To this end, computational scientists, computer scientists, and mathematicians in Brookhaven Lab’s Computational Science Initiative, which encompasses SDCC, are developing programming tools, numerical models, and data-mining algorithms. Part of SDCC’s mission is to provide computing and networking resources in support of these activities.

    A Data Storage, Computing, and Networking Infrastructure

    Housed inside SDCC are more than 60,000 computing cores, 250 computer racks, and tape libraries capable of holding up to 90,000 magnetic storage tape cartridges that are used to store, process, analyze, and distribute the experimental data. The facility provides approximately 90 percent of the computing capacity for analyzing data from the STAR and PHENIX experiments, and serves as the largest of the 12 Tier 1 computing centers worldwide that support the ATLAS experiment. As a Tier 1 center, SDCC contributes nearly 23 percent of the total computing and storage capacity for the ATLAS experiment and delivers approximately 200 terabytes of data (picture 62 million photos) per day to more than 100 data centers globally.

    At SDCC, the High Performance Storage System (HPSS) has been providing mass storage services to the RHIC and LHC experiments since 1997 and 2006, respectively. This data archiving and retrieval software, developed by IBM and several DOE national laboratories, manages petabytes of data on disk and in robot-controlled tape libraries. Contained within the libraries are magnetic tape cartridges that encode the data and tape drives that read and write the data. Robotic arms load the cartridges into the drives and unload them upon request.

    3
    Inside one of the automated tape libraries at the Scientific Data and Computing Center (SDCC), Eric Lançon, director of SDCC, holds a magnetic tape cartridge. When scientists need data, a robotic arm (the piece of equipment in front of Lançon) retrieves the relevant cartridges from their slots and loads them into drives in the back of the library.

    When ranked by the volume of data stored in a single HPSS, Brookhaven’s system is the second largest in the nation and the fourth largest in the world. Currently, the RACF operates nine Oracle robotic tape libraries that constitute the largest Oracle tape storage system in the New York tri-state area. Contained within this system are nearly 70,000 active cartridges with capacities ranging from 800 gigabytes to 8.5 terabytes, and more than 100 tape drives. As the volume of scientific data to be stored increases, more libraries, tapes, and drives can be added accordingly. In 2006, this scalability was exercised when HPSS was expanded to accommodate data from the ATLAS experiment at LHC.

    “The HPSS system was deployed in the late 1990s, when the RHIC accelerator was coming on line. It allowed data from RHIC experiments to be transmitted via network to the data center for storage—a relatively new idea at the time,” said Shigeki Misawa, manager of Mass Storage and General Services at Brookhaven Lab. Misawa played a key role in the initial evaluation and configuration of HPSS, and has guided the system through significant changes in hardware (network equipment, storage systems, and servers) and operational requirements (tape drive read/write rate, magnetic tape cartridge capacity, and data transfer speed). “Prior to this system, data was recorded on magnetic tape at the experiment and physically moved to the data center,” he continued.

    Over the years, SDCC’s HPSS has been augmented with a suite of optimization and monitoring tools developed at Brookhaven Lab. One of these tools is David Yu’s scheduling software that optimizes the retrieval of massive amounts of data from tape storage. Another, developed by Jérôme Lauret, software and computing project leader for the STAR experiment, is software for organizing multiple user requests to retrieve data more efficiently.

    Engineers in the Mass Storage Group—including Tim Chou, Guangwei Che, and Ognian Novakov—have created other software tools customized for Brookhaven Lab’s computing environment to enhance data management and operation abilities and to improve the effectiveness of equipment usage.

    STAR experiment scientists have demonstrated the capabilities of SDCC’s enhanced HPSS, retrieving more than 4,000 files per hour (a rate of 6,000 gigabytes per hour) while using a third of HPSS resources. On the data archiving side, HPSS can store data in excess of five gigabytes per second.

    As demand for mass data storage spreads across Brookhaven, access to HPSS is being extended to other research groups. In the future, SDCC is expected to provide centralized mass storage services to multi-experiment facilities, such as the Center for Functional Nanomaterials and the National Synchrotron Light Source II—two more DOE Office of Science User Facilities at Brookhaven.

    “The tape library system of SDCC is a clear asset for Brookhaven’s current and upcoming big data science programs,” said SDCC Director Eric Lançon. “Our expertise in the field of data archiving is acknowledged worldwide.”

    See the full article here .

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    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
    i1

     
  • richardmitnick 2:53 pm on June 13, 2017 Permalink | Reply
    Tags: , Bs meson, FNAL CDF, , ,   

    From FNAL: “Bs matter-antimatter oscillations go at 3 trillion times a second” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

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

    June 13, 2017
    Troy Rummler

    The Standard Model of physics makes some not-so-standard predictions about our universe.

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

    Fermilab has pioneered extremely precise technologies that put these theories to the test, including the CDF experiment, which confirmed in 2006 that, yes, a Bs (pronounced “B sub s”) meson actually does switch between matter and antimatter 3 trillion times a second.

    FNAL Tevatron

    FNAL/Tevatron map


    FNAL/Tevatron DZero detector


    FNAL/Tevatron CDF detector

    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. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 11:26 am on June 8, 2017 Permalink | Reply
    Tags: , , CDF rounds up the final meson, FNAL CDF, , , ,   

    From FNAL: “CDF rounds up the final meson” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

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

    June 8, 2017
    Troy Rummler

    1
    FNAL Tevatron CDF

    On March 5, 1998, Fermilab announced it had discovered the Bc meson. This particle was the last of 15 unexcited quark-antiquark pairs to be discovered. The first one had been discovered 50 years earlier in cosmic rays, but this flighty character, which lives just 0.46 picoseconds, could be found only as a product of powerful, high-energy particle collisions.

    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. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 11:12 am on June 3, 2017 Permalink | Reply
    Tags: , , FNAL CDF, , ,   

    From FNAL: ” CDF makes first use of silicon vertex detectors in a hadron collider environment” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

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

    June 3, 2017
    Troy Rummler

    1
    In the early 1990s, the CDF collaboration installed the world’s first silicon detector in a hadron collider. Silicon detectors are now a mainstay for tracking short-lived particles very close to the collision point, but for years they were thought too fragile and too difficult to work with for anything besides small-scale experiments. CDF collaborators also developed a hardware system that could use the vast amount of data from the silicon detector in real time to detect displaced vertices, which enabled them to record world-leading-sized samples of beauty hadrons. Fermilab collaborators Aldo Menzione and Luciano Ristori developed CDF’s silicon vertex detector and were awarded the 2009 Panofsky Prize for their work, one of the highest honors a physicist can receive.

    FNAL Tevatron

    FNAL/Tevatron map


    FNAL/Tevatron DZero detector


    FNAL/Tevatron CDF detector

    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. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 4:13 pm on September 13, 2016 Permalink | Reply
    Tags: , , D+ mesons, FNAL CDF, , Strong interaction   

    From FNAL: “CDF can’t stop being charming” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

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

    September 8, 2016
    Jeffrey Appel

    FNAL/Tevatron map
    FNAL/Tevatron map

    FNAL/Tevatron CDF detector
    FNAL/Tevatron CDF detector

    Good news: there is a theory to describe the strong interaction, the interactions that bind the constituents of protons and neutrons together and create the strong force. Bad news: Calculations using the theory can be made in only a limited selection of natural phenomena.

    Quantitative predictions for interactions beyond that subset depend on measurements. This can be either for direct use or to help guide the theory about the inputs used in calculations, such as the distributions of the quark and gluon constituents inside protons and neutrons. Using the production of particles containing heavy charm and bottom quarks helps especially with gluon distributions.

    CDF is now reporting new measurements of the rate of production at the Tevatron of D+ mesons, which contain charm quarks. Furthermore, the new measurements are made in the region where the D+ mesons have the smallest momentum transverse to the incident beams. This is the region that is the hardest to calculate using the theory of strong interactions and has never been explored in proton-antiproton collisions.

    1
    This plot shows the measures, in bins of momentum transverse to incident protons, of the average probability of producing a D+ meson at the Tevatron. Shown as bands are the averages predicted in the same bins by the latest theoretical calculations.

    To probe such small transverse momenta, CDF physicists examined all types of interactions of the incoming protons and antiprotons, not just those selected to study rare occurrences.

    The results of this new analysis appear in the figure. The measurements lie within the band of uncertainty of the theoretical predictions. Using the results here, theorists can reduce the size of the band of uncertainty. They might also be able to improve the general trend of the predictions to agree better with the trends in the measurements.

    This measurement is an example of CDF’s continuing effort to produce unique and useful results that complement and supplement those of the LHC. These help improve our understanding of the fundamental forces of nature.

    Learn more.

    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. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 4:00 pm on June 29, 2016 Permalink | Reply
    Tags: , , , FNAL CDF, , , , Tetraquarks? For real?   

    From Symmetry: “LHCb discovers family of tetraquarks” 

    Symmetry Mag

    Symmetry

    06/29/16
    Sarah Charley

    1
    LHCb. Courtesy of CERN

    Researchers found four new particles made of the same four building blocks.

    It’s quadruplets! Syracuse University researchers on the LHCb experiment confirmed the existence of a new four-quark particle and serendipitously discovered three of its siblings.

    Quarks are the solid scaffolding inside composite particles like protons and neutrons. Normally quarks come in pairs of two or three, but in 2014 LHCb researchers confirmed the existence four-quark particles and, one year later, five-quark particles.

    The particles in this new family were named based on their respective masses, denoted in mega-electronvolts: X(4140), X(4274), X(4500) and X(4700). Each particle contains two charm quarks and two strange quarks arranged in a unique way, making them the first four-quark particles composed entirely of heavy quarks. Researchers also measured each particle’s quantum numbers, which describe their subatomic properties. Theorists will use these new measurements to enhance their understanding of the formation of particles and the fundamental structures of matter.

    “What we have discovered is a unique system,” says Tomasz Skwarnicki, a physics professor at Syracuse University. “We have four exotic particles of the same type; it’s the first time we have seen this and this discovery is already helping us distinguish between the theoretical models.”

    Evidence of the lightest particle in this family of four and a hint of another were first seen by the CDF experiment at the US Department of Energy’s Fermi National Accelerator Lab in 2009.

    FNAL/Tevatron CDF detector
    FNAL/Tevatron machine
    FNAL/Tevatron map
    CDF; Tevatron; Tevtron map

    However, other experiments were unable to confirm this observation until 2012, when the CMS experiment at CERN reported seeing the same particle-like bumps with a much greater statistical certainty.

    CERN/CMS Detector
    CERN/CMS Detector

    Later, the D0 collaboration at Fermilab also reported another observation of this particle.

    FNAL/Tevatron DZero detector
    D0/FNAL

    “It was a long road to get here,” says University of Iowa physicist Kai Yi, who works on both the CDF and CMS experiments. “This has been a collective effort by many complementary experiments. I’m very happy that LHCb has now reconfirmed this particle’s existence and measured its quantum numbers.”

    The US contribution to the LHCb experiment is funded by the National Science Foundation.

    LHCb researcher Thomas Britton performed this analysis as his PhD thesis at Syracuse University.

    “When I first saw the structures jumping out of the data, little did I know this analysis would be such an aporetic saga,” Britton says. “We looked at every known particle and process to make sure these four structures couldn’t be explained by any pre-existing physics. It was like baking a six-dimensional cake with 98 ingredients and no recipe—just a picture of a cake.”

    Even though the four new particles all contain the same quark composition, they each have a unique internal structure, mass and their own sets of quantum numbers. These characteristics are determined by the internal spatial configurations of the quarks.

    “The quarks inside these particles behave like electrons inside atoms,” Skwarnicki says. “They can be ‘excited’ and jump into higher energy orbitals. The energy configuration of the quarks gives each particle its unique mass and identity.”

    According to theoretical predictions, the quarks inside could be tightly bound (like three quarks packed inside a single proton) or loosely bound (like two atoms forming a molecule.) By closely examining each particle’s quantum numbers, scientists were able to narrow down the possible structures.

    “The molecular explanation does not fit with the data,” Skwarnicki says. “But I personally would not conclude that these are definitely tightly bound states of four quarks. It could be possible that these are not even particles. The result could show the complex interplays of known particle pairs flippantly changing their identities.”

    Theorists are currently working on models to explain these new results—be it a family of four new particles or bizarre ripple effects from known particles. Either way, this study will help shape our understanding of the subatomic universe.

    “The huge amount of data generated by the LHC is enabling a resurgence in searches for exotic particles and rare physical phenomena,” Britton says. “There’s so many possible things for us to find and I’m happy to be a part of it.”

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 10:31 am on September 24, 2015 Permalink | Reply
    Tags: , , FNAL CDF, , ,   

    From FNAL: “Frontier Science Result: CDF More than expected” 

    FNAL II photo

    [I know that this article is not for the technically feint of heart. I cannot claim to understand it. I present it to show that the Tevatron produced data which is still being sifted today and which remains relevant, in spite of the move of HEP to the Large Hadron Collider at CERN.]

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

    Sept. 24, 2015
    Andy Beretvas

    Temp 1
    This plot shows the invariant-mass distribution of the Bc+ → J/ψμ+ candidate events using the full CDF data sample with a Monte Carlo-simulated signal sample. The calculated backgrounds are superimposed

    In 1998 CDF was the first to observe the Bc+ meson, which consists of two quarks: an antibottom quark and a charmed quark. The discovery consisted of a measurement involving approximately 20 decays in which the decay products were a J/ψ, a charged lepton (muon or electron) and an unobserved neutrino.

    FNAL CDF
    CDF

    Using the full Tevatron Run II data set, we now observe approximately 740 events in the muon decay mode. CDF looked for a signature of three muons, the mass of two oppositely charged muons being consistent with that of the J/ψ particle. This larger data set allows us to make the first measurement of the production cross section of the Bc+ meson.

    FNAL Tevatron
    Tevatron map

    One of the principal challenges in the analysis was the determination of the backgrounds, which are shown in the above figure. In the largest background, the J/ψ is correctly identified, but the third muon is misidentified as a pion, kaon or proton. Of the 1,370 Bc+ candidates, 630 are identified as being background.

    In order to minimize the error, we compared our measurement to that of a decay that is already well measured (B+ → J/ψ + K+). The cross section for B+ is 2.78 ± 0.24 microbarns for conditions very similar to our measurement of the Bc+. Using well-known properties of the B+ decay, we find the final cross section for Bc+ production to be 29 ± 4 nanobarns.

    Our result is higher than the theory expectation (by two standard deviations), but the theory calculation was done 10 years ago (kT factorization). Measurements at the LHC collider, where the cross sections should be many times larger, could resolve this problem in our understanding of a meson that is both beautiful and charmed.

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

    CDF scientists performed a job well done in determining the background, a difficult, interesting challenge.

    Learn more.

    This is my last Frontier Science Result for CDF. I’d like to thank my CDF colleagues for writing so many interesting and important physics papers that were the subject of this column. Finally, Leah Hesla deserves special praise for her wonderful job of editing.

    Fermilab Leah Hesla
    Leah Hesla

    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. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 9:37 am on August 27, 2015 Permalink | Reply
    Tags: , , FNAL CDF, ,   

    From FNAL- “Frontier Science Result: CDF Never alone” 

    FNAL II photo

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

    Aug. 27, 2015
    Matthew Jones

    2

    1
    The top plot shows the fraction of charged particles produced around a Ds+ meson that are kaons as a function of the particle transverse momentum. The bottom plot shows the fraction produced around a D+ meson. A larger kaon fraction is observed in association with Ds+ production because the kaon contains the strange quark produced in association with the antistrange quark found in the Ds+ meson. The pair of strange quarks is created as the gluon string breaks at the end closest to the heavy quark.

    When produced in high-energy collisions, quarks are never observed in isolation as free particles. Instead, all quarks remain connected to other fundamental particles produced in a collision by a “string” of gluons.

    At low energies, these gluons bind quarks and antiquarks together to form stable mesons. But at higher energies, the string can break and reconnect to new quark-antiquark pairs that are created out of the energy stored in the stretched string.

    We can watch this process in action by studying bottom or charm quarks, which are initially produced in proton-antiproton collisions. The bottom and charm quarks can ultimately be found inside a heavy meson, such as a B+ or D+, respectively. But once the quark is bound inside one of these particles, what happens to the rest of its string?

    Scientists have tuned models to describe the average properties of the mesons created in the fragmentation process, but it would be interesting to watch what happens to the end of the string that remains immediately after the part connected to the heavy quark is broken.

    Recently, the CDF experiment did exactly this by looking at the properties of kaons produced in association with Ds+ mesons.

    FNAL CDF
    CDF

    In this case, when a gluon string breaks, the strange quark in a K- is produced at the same time as the antistrange quark needed to form the Ds+ meson.

    Kaons produced in this way were shown to have distinctly different properties when compared to kaons produced in association with D+ mesons, which instead contain an antidown quark, consistent with fragmentation models.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 9:38 am on April 9, 2015 Permalink | Reply
    Tags: , , FNAL CDF, , ,   

    From FNAL- “Frontier Science Result: CDF – Happy hunting grounds 

    FNAL Home

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

    April 9, 2015
    Fabrizio Margaroli and Andy Beretvas

    1
    This artistic view of a Feynman diagram shows the process of proton colliding with an antiproton, producing a W’, which then decays into a top quark and an antibottom quark.

    We understand nature in terms of elementary particles interacting through a set of well-known forces, which are mediated by other particles. These are the graviton (mediator of gravity), the photon (mediator of electromagnetism), the gluon (mediator of the strong force), the W and Z bosons (mediators of the weak force) and the Higgs boson. We produce and detect these particles (except the graviton) in large numbers at colliders around the world.

    But is that all the universe is made of — a handful of different types of particles? We have good reasons to believe that this is not the case. New forces can exist, and the corresponding mediating particles could be seen at colliders. However, such particles have been hunted extensively at the Large Hadron Collider without success so far.

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

    If new forces are hiding so well from physicists’ determination to discover them, either they would have to be mediated by very massive bosons or these bosons would have to interact very weakly with ordinary stuff.

    The W and Z boson serve as a good model for this kind of exotic stuff: In fact they are both very heavy compared to their peers and interact weakly with ordinary matter. They live very shortly before decaying into more “mundane” particles, most of the time quarks. If new forces were to exist with such properties, then the LHC would not be the best hunting ground because of its enormous production rate of quarks from ordinary forces.

    A new analysis of Tevatron data performed by the CDF collaboration searches for the existence of new electrically charged, massive particles (a W’ boson) decaying into a top and a bottom quark. Top and bottom quarks leave striking signatures in the detector; W’ events would resemble ordinary production of such quarks if not for the extra energy provided by the decay of the parent particle.

    FNAL Tevatron
    FNAL Tevatron machine
    Tevatron

    FNAL CDF
    CDF part of the Tevatron

    The search for a W’ with data from the CDF experiment turns out to be the most sensitive for such a heavy particle with mass below 650 GeV (approximately 700 times the proton mass). Unfortunately, no surprise turned out from CDF data. The ball is now again in the hands of the LHC experiments!

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
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