Local alignment of the BABAR Silicon Vertex Tracking detector
International Nuclear Information System (INIS)
The BABAR Silicon Vertex Tracker (SVT) is a five-layer double-sided silicon detector designed to provide precise measurements of the position and direction of primary tracks, and to fully reconstruct low-momentum tracks produced in e+e- collisions at the PEP-II asymmetric collider at Stanford Linear Accelerator Center. This paper describes the design, implementation, performance, and validation of the local alignment procedure used to determine the relative positions and orientations of the 340 SVT wafers. This procedure uses a tuned mix of in situ experimental data and complementary lab-bench measurements to control systematic distortions. Wafer positions and orientations are determined by minimizing a χ2 computed using these data for each wafer individually, iterating to account for between-wafer correlations. A correction for aplanar distortions of the silicon wafers is measured and applied. The net effect of residual misalignments on relevant physical variables is evaluated in special control samples. The BABAR data-sample collected between November 1999 and April 2008 is used in the study of the SVT stability.
PIN Photodiodes for Radiation Monitoring and Protection in the BaBar Silicon Vertex Tracker
Babar Collaboration; T.I. Meyer
2000-01-01
We discuss the design, implementation and performance of the radiation monitoring and protection system used by the Silicon Vertex Tracker (SVT) in the BaBar detector. Using 12 reverse-biased PIN photodiodes mounted around the beampipe near the IP, we are able to provide instantaneous radiation dose rates, absorbed dose integrals, and active protection that aborts the circulating beams in the PEP-II storage ring when radiation levels exceed user-defined thresholds. The system has reliably pro...
Managing Bias Leakage Currents and High Data Rates in the BABAR Silicon Vertex Tracker
Garra-Tico, J; Bondioli, M; Bruinsma, M; Curry, S; Kirkby, D; Burke, S; Callahan, D; Campagnari, C; Cunha, A; Hale, D; Kyre, S; Richman, J; Beck, T; Eisner, A M; Kroseberg, J; Lockman, W S; Nesom, G; Seiden, A; Spradlin, P; Winstrom, L; Brown, D; Dardin, S; Goozen, F; Kerth, L T; Lynch, G; Roe, N A; Anderson, J; Chen, C; Lae, C K; Roberts, D; Simi, G; Tuggle, J; Lazzaro, A; Lombardo, V; Palombo, F; Ratti, L; Angelini, C; Batignani, G; Bettarini, S; Bosi, F; Bucci, F; Calderini, G; Carpinelli, M; Ceccanti, M; Cenci, R; Cervelli, A; Forti, F; Giorgi, M A; Lusiani, A; Mammini, P; Manfredi, P F; Marchiori, G; Mazur, M; Morganti, M; Morsani, F; Neri, N; Paoloni, E; Profeti, A; Rama, M; Rizzo, G; Walsh, J; Elmer, P; Long, O; Charles, E; Perazzo, A; Burchat, P; Edwards, A J; Miyashita, T S; Majewski, S; Petersen, B A; Bona, M; Bianchi, F; Gamba, D; Trapani, P; Bomben, M; Bosisio, L; Cartaro, C; Dittongo, S; Lanceri, L; Vitale, L; Azzolini, V; Lopez-March, N; Gao, Y Y; Gritsan, A V; Guo, Z J
2008-01-01
The silicon vertex tracker at the BABAR experiment is the primary device used in measuring the distance between B0 and meson decay vertices for the extraction of CP asymmetries. It consists of five layers of double-sided, AC-coupled silicon modules, read out by custom integrated circuits. It has run well consistently for eight years. I report on three years of experience in managing problematic bias leakage currents in the fourth layer. In addition, I report on recent success in decreasing the data acquisition time by reducing the readout window.
Belle II Silicon Vertex Detector
Mohanty, Gagan B
2015-01-01
The Belle II experiment at the SuperKEKB collider in Japan is designed to indirectly probe new physics using approximately 50 times the data recorded by its predecessor. An accurate determination of the decay-point position of subatomic particles such as beauty and charm hadrons as well as a precise measurement of low-momentum charged particles will play a key role in this pursuit. These will be accomplished by a vertex detector, which comprises two layers of pixelated silicon detector and four layers of silicon vertex detector. We describe herein the design, prototyping and construction efforts of the Belle-II silicon vertex detector that is aimed to be commissioned towards the middle of 2017.
The CDF Silicon Vertex Detector
International Nuclear Information System (INIS)
A silicon strip vertex detector was designed, constructed and commissioned at the CDF experiment at the Tevatron collider at Fermilab. The mechanical design of the detector, its cooling and monitoring are presented. The front end electronics employing a custom VLSI chip, the readout electronics and various components of the SVX system are described. The system performance and the experience with the operation of the
The CDF Silicon Vertex Detector
International Nuclear Information System (INIS)
A silicon strip vertex detector was designed, constructed and commissioned at the CDF experiment at the Tevatron collider at Fermilab. The mechanical design of the detector, its cooling and monitoring are presented. The front end electronics employing a custom VLSI chip, the readout electronics and various components of the SVX system are described. The system performance and the experience with the operation of the detector in the radiation environment are discussed. The device has been taking colliding beams data since May of 1992, performing at its best design specifications and enhancing the physics program of CDF. (orig.)
The CDF Silicon Vertex Trigger
International Nuclear Information System (INIS)
The Collider Detector at Fermilab (CDF) experiment's Silicon Vertex Trigger (SVT) is a system of 150 custom 9U VME boards that reconstructs axial tracks in the CDF silicon strip detector in a 15 μs pipeline. SVT's 35 μm impact parameter resolution enables CDF's Level 2 trigger to distinguish primary and secondary particles, and hence to collect large samples of hadronic bottom and charm decays. We review some of SVT's key design features. Speed is achieved with custom VLSI pattern recognition, linearized track fitting, pipelining, and parallel processing. Testing and reliability are aided by built-in logic state analysis and test-data sourcing at each board's input and output, a common interboard data link, and a universal 'Merger' board for data fan-in/fan-out. Speed and adaptability are enhanced by use of modern FPGAs
The CDF Silicon Vertex Trigger
Energy Technology Data Exchange (ETDEWEB)
Ashmanskas, Bill E-mail: wja@hep.anl.gov; Barchiesi, A.; Bardi, A.; Bari, M.; Baumgart, M.; Belforte, S.; Berryhill, J.; Bogdan, M.; Carosi, R.; Cerri, A.; Chlachidze, G.; Culbertson, R.; Dell' Orso, M.; Donati, S.; Fiori, I.; Frisch, H.; Galeotti, S.; Giannetti, P.; Glagolev, V.; Leger, A.; Liu, Y.; Maruyama, T.; Meschi, E.; Moneta, L.; Morsani, F.; Nakaya, T.; Punzi, G.; Rescigno, M.; Ristori, L.; Sanders, H.; Sarkar, S.; Semenov, A.; Shochet, M.; Speer, T.; Spinella, F.; Vataga, H.; Wu, X.; Yang, U.K.; Zanello, L.; Zanetti, A.M
2004-02-01
The Collider Detector at Fermilab (CDF) experiment's Silicon Vertex Trigger (SVT) is a system of 150 custom 9U VME boards that reconstructs axial tracks in the CDF silicon strip detector in a 15 {mu}s pipeline. SVT's 35 {mu}m impact parameter resolution enables CDF's Level 2 trigger to distinguish primary and secondary particles, and hence to collect large samples of hadronic bottom and charm decays. We review some of SVT's key design features. Speed is achieved with custom VLSI pattern recognition, linearized track fitting, pipelining, and parallel processing. Testing and reliability are aided by built-in logic state analysis and test-data sourcing at each board's input and output, a common interboard data link, and a universal 'Merger' board for data fan-in/fan-out. Speed and adaptability are enhanced by use of modern FPGAs.
The CDF Silicon Vertex Trigger
Barchiesi, A; Bari, M; Baumgart, M D; Belforte, S; Berryhill, J W; Bogdan, M; Carosi, R; Cerri, A; Chlachidze, G; Culbertson, R; Dell'Orso, Mauro; Donati, S; Fiori, I; Frisch, H; Galeotti, S; Giannetti, P; Glagolev, V; Léger, A; Liu, Y; Maruyama, T; Meschi, E; Moneta, L; Morsani, F; Nakaya, T; Punzi, G; Rescigno, M; Ristori, L; Sanders, H; Sarkar, S; Semenov, A; Shochet, M J; Speer, T; Spinella, F; Vataga, H; Wu, X; Yang, U K; Zanello, L; Zanetti, A M
2004-01-01
The CDF experiment's Silicon Vertex Trigger is a system of 150 custom 9U VME boards that reconstructs axial tracks in the CDF silicon strip detector in a 15 microsecond pipeline. SVT's 35 micron impact parameter resolution enables CDF's Level 2 trigger to distinguish primary and secondary particles, and hence to collect large samples of hadronic bottom and charm decays. We review some of SVT's key design features. Speed is achieved with custom VLSI pattern recognition, linearized track fitting, pipelining, and parallel processing. Testing and reliability are aided by built-in logic state analysis and test-data sourcing at each board's input and output, a common inter-board data link, and a universal "Merger" board for data fan-in/fan-out. Speed and adaptability are enhanced by use of modern FPGAs.
Silicon vertex detector for superheavy elements identification
Directory of Open Access Journals (Sweden)
Bednarek A.
2012-07-01
Full Text Available Silicon vertex detector for superheavy elements (SHE identification has been proposed. It will be constructed using very thin silicon detectors about 5 μm thickness. Results of test of 7.3 μm four inch silicon strip detector (SSD with fission fragments and α particles emitted by 252Cf source are presented
Silicon vertex detector for CDF
International Nuclear Information System (INIS)
The major reason for building a vertex detector for CDF is the tagging of decay vertices of particles with lifetime in the 10-13/10-12 sec. range. This is a complementary approach to heavy flavour physics with respect to missing E/sub t/ and large p/sub t/ leptons. The method can be best applied to tag hadronic decays of heavy flavours, which have the largest branching ratios, but have eluded any specific tagging until now. It also works, although with somewhat reduced efficiency, in events with a semileptonic decay. All in all it promises to be a powerful tool in the search of rather elusive processes like Higgs, top, or fourth generation quark production. The additional information provided by the vertex detector will also improve significantly the resolution of the CDF central tracking system
The H1 Silicon Vertex Detector
Pitzl, D.
2000-01-01
The design, construction and performance of the H1 silicon vertex detector is described. It consists of two cylindrical layers of double sided, double metal silicon sensors read out by a custom designed analog pipeline chip. The analog signals are transmitted by optical fibers to a custom designed ADC board and are reduced on PowerPC processors. Details of the design and construction are given and performance figures from the first data taking periods are presented.
The superB silicon vertex tracker
International Nuclear Information System (INIS)
The SuperB asymmetric e+-e- collider has been designed to deliver a luminosity greater than 1036cm-2s-1 with moderate beam currents. Comparing to current B-Factories, the reduced center of mass boost of the SuperB machine requires improved vertex resolution to allow precision measurements sensitive to New Physics. We present the conceptual design of the silicon vertex tracker (SVT) for the SuperB detector with the present status of the R and D on the different options under study for its innermost Layer0.
The Belle II Silicon Vertex Detector
Energy Technology Data Exchange (ETDEWEB)
Friedl, M., E-mail: markus.friedl@oeaw.ac.at [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Ackermann, K. [MPI Munich, Föhringer Ring 6, 80805 München (Germany); Aihara, H. [University of Tokyo, Department of Physics, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Aziz, T. [Tata Institute of Fundamental Research, Experimental High Energy Physics Group, Homi Bhabha Road, Mumbai 400 005 (India); Bergauer, T. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Bozek, A. [Institute of Nuclear Physics, Division of Particle Physics and Astrophysics, ul. Radzikowskiego 152, 31 342 Krakow (Poland); Campbell, A. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Dingfelder, J. [University of Bonn, Department of Physics and Astronomy, Nussallee 12, 53115 Bonn (Germany); Drasal, Z. [Charles University, Institute of Particle and Nuclear Physics, Ke Karlovu 3, 121 16 Praha 2 (Czech Republic); Frankenberger, A. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Gadow, K. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Gfall, I. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Haba, J.; Hara, K.; Hara, T. [KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Higuchi, T. [University of Tokyo, Kavli Institute for Physics and Mathematics of the Universe, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Himori, S. [Tohoku University, Department of Physics, Aoba Aramaki Aoba-ku, Sendai 980-8578 (Japan); Irmler, C. [HEPHY – Institute of High Energy Physics, Nikolsdorfer Gasse 18, 1050 Vienna (Austria); Ishikawa, A. [Tohoku University, Department of Physics, Aoba Aramaki Aoba-ku, Sendai 980-8578 (Japan); Joo, C. [Seoul National University, High Energy Physics Laboratory, 25-107 Shinlim-dong, Kwanak-gu, Seoul 151-742 (Korea, Republic of); and others
2013-12-21
The KEKB machine and the Belle experiment in Tsukuba (Japan) are now undergoing an upgrade, leading to an ultimate luminosity of 8×10{sup 35}cm{sup −2}s{sup −1} in order to measure rare decays in the B system with high statistics. The previous vertex detector cannot cope with this 40-fold increase of luminosity and thus needs to be replaced. Belle II will be equipped with a two-layer Pixel Detector surrounding the beam pipe, and four layers of double-sided silicon strip sensors at higher radii than the old detector. The Silicon Vertex Detector (SVD) will have a total sensitive area of 1.13m{sup 2} and 223,744 channels—twice as many as its predecessor. All silicon sensors will be made from 150 mm wafers in order to maximize their size and thus to reduce the relative contribution of the support structure. The forward part has slanted sensors of trapezoidal shape to improve the measurement precision and to minimize the amount of material as seen by particles from the vertex. Fast-shaping front-end amplifiers will be used in conjunction with an online hit time reconstruction algorithm in order to reduce the occupancy to the level of a few percent at most. A novel “Origami” chip-on-sensor scheme is used to minimize both the distance between strips and amplifier (thus reducing the electronic noise) as well as the overall material budget. This report gives an overview on the status of the Belle II SVD and its components, including sensors, front-end detector ladders, mechanics, cooling and the readout electronics.
Mechanical design of the CDF SVX II silicon vertex detector
International Nuclear Information System (INIS)
A next generation silicon vertex detector is planned at CDF for the 1998 Tevatron collider run with the Main Injector. The SVX II silicon vertex detector will allow high luminosity data-taking, enable online triggering of secondary vertex production, and greatly increase the acceptance for heavy flavor physics at CDF. The design specifications, geometric layout, and early mechanical prototyping work for this detector are discussed
Belle II Silicon Vertex Detector: Mechanics
International Nuclear Information System (INIS)
Full text: The Belle experiment at KEK in Tsukuba, Japan and its precision measurements have led to the justification of the Nobel Prize earned by Kobayashi and Maskawa in 2008. In June 2010, the machine was brought to a halt for a promising future, namely an upgrade to Belle II which will be completed until 2015. By this time all important components are to be exchanged for an unprecedented performance boost of the accelerator (KEKB) and the Belle Detector. With this upgrade, KEKB will become SuperKEKB and beat its own luminosity world record (2.11 x 1034 cm-1s-1) by a factor of 40. The core of the Belle II Experiment is composed of a DEPFET Pixel Detector, which is surrounded by the Silicon Vertex Detector (SVD). The SVD is located close to the beam pipe to allow high precision vertex reconstruction. The proximity to the beam pipe and the high beam currents result in a very high level of background radiation for the SVD that both, the electronics and the mechanics have to cope with. The Origami sensor design was developed to provide a fast readout system at a very good signal to noise ratio. This design comes with a great performance increase that is able to fulfill with the new Belle II requirements. Nevertheless it is important to implement a light and yet stable mechanical construction that can withstand the radiation and temperature conditions without compromising the detector capabilities. (author)
Simulations of silicon vertex tracker for star experiment at RHIC
Energy Technology Data Exchange (ETDEWEB)
Odyniec, G.; Cebra, D.; Christie, W.; Naudet, C.; Schroeder, L.; Wilson, W. [Lawrence Berkeley Lab., CA (United States); Liko, D. [Institut fur Hochenenergiephysik, Vienna, (Austria); Cramer, J.; Prindle, D.; Trainor, T. [Univ. of Washington, Seattle (United States); Braithwaite, W. [Univ. of Arkansas, Little Rock (United States)
1991-12-31
The first computer simulations to optimize the Silicon Vertex Tracker (SVT) designed for the STAR experiment at RHIC are presented. The physics goals and the expected complexity of the events at RHIC dictate the design of a tracking system for the STAR experiment. The proposed tracking system will consist of a silicon vertex tracker (SVT) to locate the primary interaction and secondary decay vertices and to improve the momentum resolution, and a time projection chamber (TPC), positioned inside a solenoidal magnet, for continuous tracking.
The SVX II Silicon Vertex Detector at CDF
Energy Technology Data Exchange (ETDEWEB)
Valls, Juan A
1999-08-01
The Silicon VerteX detector (SVX II) for the CDF experiment at the Tevatron pp-bar collider is a 3-barrel 5-layer device with double-sided, AC-coupled silicon strip detectors. The readout is based on a custom IC, the SVX3 chip, capable of simultaneous acquisition, digitization and readout operation (dead-timeless). In this paper we report on the SVX II design and project status including mechanical design, frontend electronics, and data acquisition.
The SVX II Silicon Vertex Detector at CDF
International Nuclear Information System (INIS)
The Silicon VerteX detector (SVX II) for the CDF experiment at the Tevatron pp-bar collider is a 3-barrel 5-layer device with double-sided, AC-coupled silicon strip detectors. The readout is based on a custom IC, the SVX3 chip, capable of simultaneous acquisition, digitization and readout operation (dead-timeless). In this paper we report on the SVX II design and project status including mechanical design, frontend electronics, and data acquisition
The SVX II silicon vertex detector at CDF
Energy Technology Data Exchange (ETDEWEB)
Juan A. Valls
1998-12-01
The Silicon Vertex detector (SVX II) for the CDF experiment at the Tevatron p{anti p} collider is a 3-barrel 5-layer device with double-sided, AC-coupled silicon strip detectors. The readout is based on a custom IC, the SVX3 chip, capable of simultaneous acquisition, digitization and readout operation (dead-timeless). In this paper we report on the SVX II design and project status including mechanical design, frontend electronics, and data acquisition.
Progress in the construction of the CDF silicon vertex detector
International Nuclear Information System (INIS)
The mechanical design and construction progress of the CDF silicon vertex detector is described. Results on the location accuracy of the silicon strip detectors are presented and indicate an initial placement uncertainty of less than 10 μm. The water and gas cooling system, which is constructed of low mass materials and is used to remove heat from the readout electronics, is briefly described. Measurements of the performance of the silicon strip detectors are also given and show >98.5% functioning strips for the assembled SVX detector. (orig.)
Bettarini, S; Bosisio, L; Calderini, G; Campagnari, C; Dittongo, S; Forti, F; Giorgi, M A; Marchiori, G; Rizzo, G
2004-01-01
We have investigated the depletion voltage changes, the leakage current increase and the charge collection efficiency of a silicon microstrip detector identical to those used in the inner layers of the BaBar Silicon Vertex Tracker (SVT) after heavy non-uniform irradiation. A full SVT module with the front-end electronics connected has been irradiated with a 0.9 GeV electron beam up to a peak fluence of 3.5 x 10^14 e^-/cm^2, well beyond the level causing substrate type inversion. We irradiated one of the two sensors composing the module with a non-uniform profile with sigma=1.4 mm that simulates the conditions encountered in the BaBar experiment by the modules intersecting the horizontal machine plane. The position dependence of the charge collection properties and the depletion voltage have been investigated in detail using a 1060 nm LED and an innovative measuring technique based only on the digital output of the chip.
The CDF Silicon Vertex Detector for Run II
Energy Technology Data Exchange (ETDEWEB)
R. Rossin
2004-01-06
The 8 layer, 720k channel CDF Run II silicon detector is an essential part of the heavy flavor tagging and forward tracking capabilities of the CDF experiment. A summary of the experience in commissioning and operating this double-sided detector during the first 2 years of Run II is presented. The performances of the silicon in term of resolution, efficiency are also described. The results of the studies of radiation damage and the expected operational limits are discussed. A short description of the SVT, the Level 2 Silicon Vertex Trigger, one of the major upgrades related to the new silicon device is also presented. Finally, some of the many physics results achieved by means of the new Silicon+SVT machinery are also reviewed.
The CDF-II Online Silicon Vertex Tracker
Bardi, A; Carosi, R; Cerri, A; Chlachidze, G; Dell'Orso, Mauro; Donati, S; Galeotti, S; Giannetti, P; Glagolev, V; Meschi, E; Morsani, F; Passuello, D; Punzi, G; Ristori, L; Semenov, A A; Spinella, F; Barchiesi, A; Rescigno, M; Sarkar, S; Zanello, L; Bari, M; Belforte, S; Zanetti, A M; Fiori, I; Ashmanskas, B; Baumgart, M D; Berryhill, J W; Bogdan, M; Culbertson, R J; Frisch, H; Nakaya, T; Sanders, H; Shochet, M J; Yang, U; Liu, Y; Moneta, L; Speer, T; Wu, X
2001-01-01
The Online Silicon Vertex Tracker is the new CDF-II level 2 trigger processor designed to reconstruct 2-D tracks within the Silicon Vertex Detector with high speed and accuracy. By performing a precise measurement of impact parameters the SVT allows tagging online B events which typically show displaced secondary vertices. Physics simulations show that this will greatly enhance the CDF-II B-physics capability. The SVT has been fully assembled and operational since the beginning of Tevatron RunII in April 2001. In this paper we briefly review the SVT design and physics motivation and then describe its performance during the early phase (April-October 2001) of run II.
The silicon vertex locator for the LHCb upgrade
Energy Technology Data Exchange (ETDEWEB)
Head, Tim, E-mail: thead@cern.ch
2014-11-21
The upgrade of the LHCb experiment, planned for 2018, will transform the entire readout to a triggerless system being read out at 40 MHz. The upgraded silicon vertex detector (VELO) must be light weight, radiation hard, and compatible with LHC vacuum requirements. It must be capable of fast pattern recognition, fast track reconstruction and high precision vertexing. This challenge is being met with a new VELO design based on hybrid pixel detectors positioned to within 5 mm of the LHC colliding beams. The detector will be shielded from the beam by a ∼300μm thick aluminium foil. Evaporative CO{sub 2} coolant circulating in micro-channels embedded in a thin silicon substrate will be used for cooling.
Data scanner system of the BELLE silicon vertex detector
Energy Technology Data Exchange (ETDEWEB)
Fukunaga, C. [Tokyo Metropolitan Univ. (Japan); Korhonen, T. [Univ. of Helsinki (Finland). Research Inst. of High Energy Physics; Tanaka, M.; Ikeda, H. [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan). Dept. of Physics
1996-02-01
A data scanner system, which is a part of the front-end data acquisition system of the BELLE silicon vertex detector, makes an analog-to-digital conversion of preamplified signals from the detector and stores digitized data into local memory. The sequence control and buffer managing are performed by a software process of an on-board CPU. With this data scanner system, the authors can achieve data taking with less than 10% dead time up to 800 Hz trigger rate.
Silicon vertex detector upgrade in the ALPHA experiment
Amole, C; Ashkezari, M.D; Baquero-Ruiz, M; Bertsche, W; Burrows, C; Butler, E; Capra, A; Cesar, C.L; Chapman, S; Charlton, M; Deller, A; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M.C; Gill, D.R; Gutierrez, A; Hangst, J.S; Hardy, W.N; Hayden, M.E; Humphries, A.J; Isaac, C.A; Jonsell, S; Kurchaninov, L; Little, A; Madsen, N; McKenna, J.T.K; Menary, S; Napoli, S.C; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Rasmussen, C.Ø; Robicheaux, F; Sacramento, R.L; Sampson, J.A; Sarid, E; Seddon, D; Silveira, D.M; So, C; Stracka, S; Tharp, T; Thompson, R.I; Thornhill, J; Tooley, M.P; Van Der Werf, D.P; Wells, D
2013-01-01
The Silicon Vertex Detector (SVD) is the main diagnostic tool in the ALPHA-experiment. It provides precise spatial and timing information of antiproton (antihydrogen) annihilation events (vertices), and most importantly, the SVD is capable of directly identifying and analysing single annihilation events, thereby forming the basis of ALPHA ' s analysis. This paper describes the ALPHA SVD and its upgrade, installed in the ALPHA ' s new neutral atom trap.
The STAR silicon vertex tracker: a large area silicon drift detector
Lynn, D; Beuttenmüller, Rolf H; Caines, H; Chen, W; Dimassimo, D; Dyke, H; Elliot, D; Eremin, V; Grau, M; Hoffmann, G W; Humanic, T; Ilyashenko, Yu S; Kotov, I; Kraner, H W; Kuczewski, P; Leonhardt, B; Li, Z; Liaw, C J; Lo Curto, G; Middelkamp, P; Minor, R; Munhoz, M; Ott, G; Pandey, S U; Pruneau, C A; Rykov, V L; Schambach, J; Sedlmeir, J; Soja, B; Sugarbaker, E R; Takahashi, J; Wilson, K; Wilson, R
2000-01-01
The Solenoidal Tracker At RHIC-Silicon Vertex Tracker (STAR-SVT) is a three barrel microvertex detector based upon silicon drift detector technology. As designed for the STAR-SVT, silicon drift detectors (SDDs) are capable of providing unambiguous two-dimensional hit position measurements with resolutions on the order of 20 mu m in each coordinate. Achievement of such resolutions, particularly in the drift direction coordinate, depends upon certain characteristics of silicon and drift detector geometry that are uniquely critical for silicon drift detectors hit measurements. Here we describe features of the design of the STAR-SVT SDDs and the front-end electronics that are motivated by such characteristics.
Aubert, B.; Bazan, A.; Boucham, A.; Boutigny, D.; Bonis, I.; Favier, J.; Gaillard, JM; Jeremie, A.; Karyotakis, Y.; T. Le Flour(LAPP, Annecy); Lees, JP; Lieunard, S; Petitpas, P.; Robbe, P; Tisserand, V.
2001-01-01
This is the pre-print version of the Article. The official published version can be accessed from the link below. Copyright @ 2002 Elsevier. BABAR, the detector for the SLAC PEP-II asymmetric e+e− B Factory operating at the (4S) resonance, was designed to allow comprehensive studies of CP-violation in B-meson decays. Charged particle tracks are measured in a multi-layer silicon vertex tracker surrounded by a cylindrical wire drift chamber. Electromagnetic showers from electrons and photon...
The silicon strip vertex detector of the Belle II experiment
Onuki, Yoshiyuki
2014-11-01
The Belle II upgrade of the Belle experiment will extend the search for physics beyond the standard model. The upgrade is currently under construction, and foreseen to complete in time for the physics run scheduled for 2016. The vertex detector of the Belle II comprises two types of silicon detectors: the pixel detector (PXD) and the strip detector (SVD) using double-sided silicon strip detector (DSSD). One of the most characteristic features of the SVD is a unique chip-on-sensor scheme which enabling good signal-to-noise (S/N) ratio while reducing the material budget. This paper describes the implementation of the scheme, status and future prospects of the Belle II SVD.
The silicon vertex detector of the Belle II experiment
Adamczyk, K.; Aihara, H.; Angelini, C.; Aziz, T.; Babu, V.; Bacher, S.; Bahinipati, S.; Barberio, E.; Baroncelli, T.; Basith, A. K.; Batignani, G.; Bauer, A.; Behera, P. K.; Bergauer, T.; Bettarini, S.; Bhuyan, B.; Bilka, T.; Bosi, F.; Bosisio, L.; Bozek, A.; Buchsteiner, F.; Casarosa, G.; Ceccanti, M.; Červenkov, D.; Chendvankar, S. R.; Dash, N.; Divekar, S. T.; Doležal, Z.; Dutta, D.; Forti, F.; Friedl, M.; Hara, K.; Higuchi, T.; Horiguchi, T.; Irmler, C.; Ishikawa, A.; Jeon, H. B.; Joo, C. W.; Kandra, J.; Kang, K. H.; Kato, E.; Kawasaki, T.; Kodyš, P.; Kohriki, T.; Koike, S.; Kolwalkar, M. M.; Kvasnička, P.; Lanceri, L.; Lettenbicher, J.; Mammini, P.; Mayekar, S. N.; Mohanty, G. B.; Mohanty, S.; Morii, T.; Nakamura, K. R.; Natkaniec, Z.; Negishi, K.; Nisar, N. K.; Onuki, Y.; Ostrowicz, W.; Paladino, A.; Paoloni, E.; Park, H.; Pilo, F.; Profeti, A.; Rao, K. K.; Rashevskaya, I.; Rizzo, G.; Rozanska, M.; Sandilya, S.; Sasaki, J.; Sato, N.; Schultschik, S.; Schwanda, C.; Seino, Y.; Shimizu, N.; Stypula, J.; Tanaka, S.; Tanida, K.; Taylor, G. N.; Thalmeier, R.; Thomas, R.; Tsuboyama, T.; Uozumi, S.; Urquijo, P.; Vitale, L.; Volpi, M.; Watanuki, S.; Watson, I. J.; Webb, J.; Wiechczynski, J.; Williams, S.; Würkner, B.; Yamamoto, H.; Yin, H.; Yoshinobu, T.
2016-07-01
The silicon vertex detector of the Belle II experiment, structured in a lantern shape, consists of four layers of ladders, fabricated from two to five silicon sensors. The APV25 readout ASIC chips are mounted on one side of the ladder to minimize the signal path for reducing the capacitive noise; signals from the sensor backside are transmitted to the chip by bent flexible fan-out circuits. The ladder is assembled using several dedicated jigs. Sensor motion on the jig is minimized by vacuum chucking. The gluing procedure provides such a rigid foundation that later leads to the desired wire bonding performance. The full ladder with electrically functional sensors is consistently completed with a fully developed assembly procedure, and its sensor offsets from the design values are found to be less than 200 μm. The potential functionality of the ladder is also demonstrated by the radioactive source test.
Heavy flavour physics at colliders with silicon strip vertex detectors
International Nuclear Information System (INIS)
The physics of heavy flavours has played a dominant role in high energy physics research ever since the discovery of charm in 1974, followed by the τ lepton in 1975 and bottom in 1977. With the startup of the large experiments at the e+e- colliders LEP and the SLC a new type of detector system has now come into operation which has a major impact on the studies of heavy flavours: the silicon strip vertex detector. The basic design principles of these novel detector systems are outlined and three representative experimental realizations are discussed. The impact of these detectors on the studies of the properties of heavy flavours is just emerging and focuses on the measurement of lifetimes and the tagging of the presence of heavy flavour hadrons in hadronic events. The tools that are being developed for these studies are described as well as details of representative analyses. The potential of these devices and the associated technological developments that were necessary for their application in the colliding beam environment is reflected in a plethora of new proposals to build sophisticated silicon detector systems for a large variety of future high energy physics applications. Two examples will be briefly sketched, a vertex detector for an asymmetric e+e- bottom factory and a large scale tracking system for a multipurpose detector at one of the new large hadron colliders. (orig.)
System software design for the CDF Silicon Vertex Detector
International Nuclear Information System (INIS)
An automated system for testing and performance evaluation of the CDF Silicon Vertex Detector (SVX) data acquisition electronics is described. The SVX data acquisition chain includes the Fastbus Sequencer and the Rabbit Crate Controller and Digitizers. The Sequencer is a programmable device for which we developed a high level assembly language. Diagnostic, calibration and data acquisition programs have been developed. A distributed software package was developed in order to operate the modules. The package includes programs written in assembly and Fortran languages that are executed concurrently on the SVX Sequencer modules and either a microvax or an SSP. Test software was included to assist technical personnel during the production and maintenance of the modules. Details of the design of different components of the package are reported
The silicon vertex detector of the Belle II experiment
Energy Technology Data Exchange (ETDEWEB)
Friedl, Markus, E-mail: friedl@hephy.a [Institute of High Energy Physics, Nikolsdorfergasse 18, A-1050 Vienna (Austria); Bergauer, Thomas; Gfall, Immanuel; Irmler, Christian; Valentan, Manfred [Institute of High Energy Physics, Nikolsdorfergasse 18, A-1050 Vienna (Austria)
2011-02-01
After 10 years of successful operation, the Belle experiment at KEK (Tsukuba, Japan) will be completed in 2010. Thereafter, a major upgrade of the KEK-B machine is foreseen until 2014, aiming at a final luminosity of 8x10{sup 35} cm{sup -2} s{sup -1}, which is about 40 times higher than the present peak value. Consequently, also the Belle experiment needs to be changed and the Silicon Vertex Detector (SVD) in particular will be completely replaced as it already operates close to its limits in the present system. The future SVD (a.k.a. SuperSVD) will consist of four layers of double-sided silicon strip detectors like the present one, but at larger radii, because it will be complemented by a two-layer pixel detector as the innermost sensing device. The SuperSVD will be entirely composed of silicon sensors made from 6 in. wafers read out by APV25 front-end chips that were originally developed for the CMS experiment at the LHC. Several years of R and D effort led to innovations such as the Origami chip-on-sensor concept and readout electronics with hit time finding which were successfully demonstrated on prototypes. These features will be included in the final system which is presently being designed. This paper will give an overview of the SuperSVD and present results from prototype tests ranging from detector modules to back-end electronics.
CDF Run IIb Silicon Vertex Detector DAQ Upgrade
Energy Technology Data Exchange (ETDEWEB)
S. Behari et al.
2003-12-18
The CDF particle detector operates in the beamline of the Tevatron proton-antiproton collider at Fermilab, Batavia, IL. The Tevatron is expected to undergo luminosity upgrades (Run IIb) in the future, resulting in a higher number of interactions per beam crossing. To operate in this dense radiation environment, an upgrade of CDF's silicon vertex detector (SVX) subsystem and a corresponding upgrade of its VME-based DAQ system has been explored. Prototypes of all the Run IIb SVX DAQ components have been constructed, assembled into a test stand and operated successfully using an adapted version of CDF's network-capable DAQ software. In addition, a PCI-based DAQ system has been developed as a fast and inexpensive tool for silicon detector and DAQ component testing in the production phase. In this paper they present an overview of the Run IIb silicon DAQ upgrade, emphasizing the new features and improvements incorporated into the constituent VME boards, and discuss a PCI-based DAQ system developed to facilitate production tests.
Silicon micro-vertex detector for Belle II
International Nuclear Information System (INIS)
The Belle experiment at the KEK B-factory is Japan provided the landmark experimental confirmation of CP violation mechanism within the standard model that led to the physics Nobel prize in 2008. In its second phase, called Belle II, it would seek for the holy-grail of new physics using rare decays of B and D mesons and tau leptons as a probe, in complimentary to the direct searches carried out with the LHC experiments. An important component of this upgrade is to replace the innermost subdetector, namely the silicon micro-vertex detector (SVD). The new SVD will, like the old one, consist of four layers of double-sided silicon strip detector, but made from 6âĂİ wafers and located at higher radii as a novel, two-layer DEPFET pixel detector will be inserted very dose to the beam- pipe. Starting with the physics motivation, we discuss the design concept, fabrication and the Indian contributions toward the Belle II SVD. (author)
TECHNICAL DESIGN REPORT OF THE FORWARD SILICON VERTEX (FVTX)
Energy Technology Data Exchange (ETDEWEB)
PHENIX EXPERIMENT; OBRIEN,E.; PAK, R.; DREES, K.A.; (PHENIX EXPERIMENT COLLABORATORS)
2007-08-01
The main goal of the RHIC heavy ion program is the discovery of the novel ultra-hot high-density state of matter predicted by the fundamental theory of strong interactions and created in collisions of heavy nuclei, the Quark-Gluon Plasma (QGP). From measurements of the large elliptic flow of light mesons and baryons and their large suppression at high transverse momentum pT that have been made at RHIC, there is evidence that new degrees of freedom, characteristic of a deconfined QCD medium, drive the dynamics of nucleus-nucleus collisions. It has been recognized, however, that the potential of light quarks and gluons to characterize the properties of the QGP medium is limited and the next phase of the RHIC program calls for the precise determination of its density, temperature, opacity and viscosity using qualitatively new probes, such as heavy quarks. We propose the construction of two Forward Silicon Vertex Trackers (FVTX) for the PHENIX experiment that will directly identify and distinguish charm and beauty decays within the acceptance of the muon spectrometers. The FVTX will provide this essential coverage over a range of forward and backward rapidities (1.2 < |y| < 2.4)--a rapidity range coverage which not only brings significantly larger acceptance to PHENIX but which is critical for separating cold nuclear matter effects from QGP effects and is critical for measuring the proton spin contributions over a significant fraction of the kinematic range of interest. In addition, the FVTX will provide greatly reduced background and improved mass resolution for dimuon events, culminating in the first measurements of the {upsilon}{prime} and Drell-Yan at RHIC. These same heavy flavor and dimuon measurements in p+p collisions will allow us to place significant constraints on the gluon and sea quark contributions to the proton's spin and to make fundamentally new tests of the Sivers function universality.
Control and data acquisition electronics for the CDF Silicon Vertex Detector
International Nuclear Information System (INIS)
A control and data acquisition system has been designed for the CDF Silicon Vertex Detector (SVX) at Fermilab. The system controls the operation of the SVX Rev D integrated circuit (SVX IC) that is used to instrument a 46,000 microstrip silicon detector. The system consists of a Fastbus Sequencer, a Crate Controller and Digitizer modules. 11 refs., 6 figs., 3 tabs
The silicon drift vertex detector for the STAR experiment at RHIC
Pandey, S U; Beuttenmüller, Rolf H; Caines, H; Chen, W; Dimassimo, D; Dyke, H; Elliot, D; Eremin, V; Grau, M; Hoffmann, G W; Humanic, T; Ilyashenko, Yu S; Kotov, I; Kraner, H W; Kuczewski, P; Leonhardt, B; Li, Z; Liaw, C J; Lo Curto, G; Middelkamp, P; Minor, R; Munhoz, M; Ott, G; Pruneau, C A; Rykov, V L; Schambach, J; Sedlmeir, J; Soja, B; Sugarbaker, E R; Takahashi, J; Wilson, K; Wilson, R
2002-01-01
The current status of the STAR Silicon Vertex Tracker (SVT) is presented. The performance of the Silicon Drift Detectors (SDD) is discussed. Results for a recent 15 layer SDD tracker which prototypes all components of the SVT are presented. The enhanced physics capabilities of the STAR detector due to the addition of the SVT are addressed.
Kalman filter tracking and vertexing in a silicon detector for neutrino physics
International Nuclear Information System (INIS)
This article describes the application of Kalman filter techniques for the tracking and vertexing of particles inside the NOMAD-STAR detector, a silicon vertex detector installed in NOMAD, one of the neutrino oscillation experiments at the CERN-SPS. The use of the Kalman filter simplifies computationally the tracking and vertex procedure for NOMAD-STAR. The alignment of NOMAD-STAR is shown as an example of the application of the Kalman filter for tracking purposes. The accuracy of the method is such that one obtains alignment residuals between 9 and 12 μm. Furthermore, a preliminary measure of the impact parameter (with an RMS ∼36 μm) illustrates the vertexing capabilities of this technique
Energy Technology Data Exchange (ETDEWEB)
Mazzoni, M.A.; /INFN, Rome
2007-04-18
The Babar experiment at the SLAC B factory has accumulated a high luminosity that offers the possibility of systematic studies of quarkonium spectroscopy and of investigating rare new phenomena. Recent results in this field are presented. In recent times spectroscopy has become exciting again, after the discovery of new states that are not easily explained by conventional models. States such as the X(3872) and the Y(4260) could be new excited charmonium states, but require precise measurements for positive identification. The BaBar experiment [1] is installed at the asymmetric storage ring PEP-II. 90% of the data accumulated by BaBar are taken at the Y(4S) (10.58 GeV) and 10% just below (10.54 GeV). The BaBar detector includes a 5-layer, double-sided silicon vertex tracker and a 40-layer drift chamber in a 1.5 T solenoidal magnetic field, which detect charged particles and measures their momenta and ionization energy losses. Photons, electrons, and neutral hadrons are detected with a CsI(Tl)-crystal electromagnetic calorimeter. An internally reflecting ring-imaging Cherenkov is also used for particle id. Penetrating muon and neutral hadrons are identified by an array of resistive-plate chambers embedded in the steel of the flux return. The detector allows good track and vertex resolution, good particle id and good photon detection so it is especially suited for spectroscopy studies.
The CDF SVX: A silicon vertex detector for a hadron collider
International Nuclear Information System (INIS)
A silicon microstrip vertex detector is being constructed as an upgrade to the CDF detector at the Fermilab Tevatron-1 anti pp collider. This device, which is designed to operate in the hadron collider environment, should allow the tagging of long-lived heavy flavors produced in anti pp collisions. The mechanical and electronic design of this device are described in this paper. (orig.)
Operation of the CDF silicon vertex detector with colliding beams at Fermilab
International Nuclear Information System (INIS)
In this paper we briefly describe the main features of the CDF Silicon Vertex Detector (SVX) and discuss its performance during actual colliding beam operation at the Fermilab Tevatron. Details on S/N ratio, alignment, resolution, and efficiency are given
Comparison of analogue and binary read-out in the silicon strips vertex detector of LHCb
Koppenburg, P
1997-01-01
97-020 This note presents single hit resolutions in the LHCb silicon strip vertex detector for various read-out schemes, depending on the number of bits used in digitization. A scan of reconstruction efficiencies and ghost hit rates for various signal/noise ratios is presented.
Design and Tests of the Silicon Sensors for the ZEUS Micro Vertex Detector
Dannheim, D.; Koetz, U; Coldewey, C.; Fretwurst, E.; Garfagnini, A.; Klanner, R.; Martens, J.; E. Koffeman; Tiecke, H.; Carlin, R.
2002-01-01
To fully exploit the HERA-II upgrade,the ZEUS experiment has installed a Micro Vertex Detector (MVD) using n-type, single-sided, silicon micro-strip sensors with capacitive charge division. The sensors have a readout pitch of 120 micrometers, with five intermediate strips (20 micrometer strip pitch). The designs of the silicon sensors and of the test structures used to verify the technological parameters, are presented. Results on the electrical measurements are discussed. A total of 1123 sen...
SVX II a silicon vertex detector for run II of the tevatron
International Nuclear Information System (INIS)
A microstrip silicon detector SVX II has been proposed for the upgrade of the vertex detector of the CDF experiment to be installed for run II of the Tevatron in 1998. Three barrels of four layers of double sided detectors will cover the interaction region. The requirement of the silicon tracker and the specification of the sensors are discussed together with the proposed R ampersand D to verify the performance of the prototypes detectors produced by Sintef, Micron and Hamamatsu
The Silicon Vertex Tracker for the Heavy Photon Search Experiment
Adrian, Per Hansson
2015-01-01
The Heavy Photon Search (HPS) is a new, dedicated experiment at Thomas Jefferson National Accelerator Facility (JLab) to search for a massive vector boson, the heavy photon (a.k.a. dark photon, \\Aprimebold{}), in the mass range 20-500~MeV/c$^{2}$ and with a weak coupling to ordinary matter. An \\Aprimebold{} can be radiated from an incoming electron as it interacts with a charged nucleus in the target, accessing a large open parameter space where the \\Aprimebold{} is relatively long-lived, leading to displaced vertices. HPS searches for these displaced \\Aprimebold{} to e$^+$e$^-$ decays using actively cooled silicon microstrip sensors with fast readout electronics placed immediately downstream of the target and inside a dipole magnet to instrument a large acceptance with a relatively small detector. With typical particle momenta of 0.5-2~GeV/c, the low material budget of 0.7\\% $\\mathbf{X_0}$ per tracking layer is key to limiting the dominant multiple scattering uncertainty and allowing efficient separation of ...
Thin pixel development for the SuperB silicon vertex tracker
International Nuclear Information System (INIS)
The high luminosity SuperB asymmetric e+e- collider, to be built near the INFN National Frascati Laboratory in Italy, has been designed to deliver a luminosity greater than 1036 cm-2 s-1 with moderate beam currents and a reduced center of mass boost with respect to earlier B-Factories. An improved vertex resolution is required for precise time-dependent measurements and the SuperB Silicon Vertex Tracker will be equipped with an innermost layer of small radius (about 1.5 cm), resolution of 10-15μm in both coordinates, low material budget (2. The ambitious goal of designing a thin pixel device with these stringent requirements is being pursued with specific R and D programs on different technologies: hybrid pixels, CMOS MAPS and pixel sensors developed with vertical integration technology. The latest results on the various pixel options for the SuperB SVT will be presented.
Research and development for the LHCb VELO a silicon microstrip vertex detector
Wright, V
2002-01-01
The LHCb experiment is a single arm spectrometer specifically designed to detect b-hadrons. In order to provide accurate vertex information silicon microstrip sensors of unique design have been produced. Their novelty stems from the complex geometry and fabrication techniques. This thesis presents the results from a series of tests on prototypes fabricated by Hamamatsu Photonics Ltd. In particular, attention has been given to a study of the effects that occur due to the introduction of a second layer of metal readout strips.
The design, construction and performance of the ALEPH silicon vertex detector
International Nuclear Information System (INIS)
The ALEPH silicon vertex detector is the first detector operating in a colliding beam environment that uses silicon strip detectors which provide readout on both sides and hence a three-dimensional point measurement for the trajectory of charged particles. The detector system was commissioned successfully at the e+e- collider LEP at the research centre CERN, Switzerland, during the year 1991 while taking data at the Z0 resonance. The achieved spatial resolution of the complete 73 728 channel device (intrinsic plus alignment) in 12 μm in the r.φ view and 12 μm in the z view. The design and construction of the entire detector system are discussed in detail and the experience gained in running the detector is described with special emphasis on the uses of this novel tracking device for the physics of short-lived heavy particles produced in the decays of the Z0 resonance. (orig.)
Electronics and mechanics for the Silicon Vertex Detector of the Belle II experiment
Energy Technology Data Exchange (ETDEWEB)
Irmler, C; Bergauer, T; Friedl, M; Gfall, I; Valentan, M, E-mail: irmler@hephy.oeaw.ac.a [Institute of High Energy Physics, Austrian Academy of Sciences, Nikolsdorfer Gasse 18, A-1050 Vienna (Austria)
2010-12-15
A major upgrade of the KEK-B factory (Tsukuba, Japan), aiming at a peak luminosity of 8 x 10{sup 35}cm{sup -2}s{sup -1}, which is 40 times the present value, is foreseen until 2014. Consequently an upgrade of the Belle detector and in particular its Silicon Vertex Detector (SVD) is required. We will introduce the concept and prototypes of the full readout chain of the Belle II SVD. Its APV25 based front-end utilizes the Origami chip-on-sensor concept, while the back-end VME system provides online data processing as well as hit time finding using FPGAs. Furthermore, the design of the double-sided silicon detectors and the mechanics will be discussed.
The CDF silicon vertex trigger for B-mesons physics study
International Nuclear Information System (INIS)
The CDF scientific program includes particularly the study of some key topics of the Standard Model: 1) constraint of the CKM matrix: CP violation in B sector (B0 → π+π-) and Bs mixing (Bs0 → Ds-π+, Bs0 → Ds-π+π-π+); 2) t-quark physics (t → Wb); and processes beyond the Standard Model - e.g., Higgs searching (MSSM) in the H → b bar b mode. All the above processes have the common feature - the presence of b-quarks (B-mesons). B hadrons of sufficiently high transverse momentum are characterized by a large mean value of distribution of the impact parameter with respect to the beam axis. That means events containing this kind of particles can be recognized and separated from non-long-lived background simply by cutting on the track's impact parameter. The upgraded CDF is equipped by the so-called Silicon Vertex Tracker (SVT), a unique electronic device for real time track reconstruction using the data from two CDF track detectors: the silicon strip vertex detector and drift chamber. The SVT is a level-2 trigger which within 10 μs reconstructs the tracks and obtains the transverse momentum (pt), azimuthal angle (φ) and impact parameter (d) with 30 μm precision. The simulation studies show the background reduction by factor 1000 for B0 π+π- by demand d > 100 μm for at least two tracks. This trigger is the first one of this sort ever used for hadron collider experiments: it enables to trigger on the secondary vertex, which opens the unique new opportunities in the heavy quark physics study. The basic logic, architecture and perspectives of SVT application are briefly described
Evaporative CO2 cooling using microchannels etched in silicon for the future LHCb vertex detector
Nomerotski, A; Collins, P; Dumps, R; Greening, E; John, M; Mapelli, A; Leflat, A; Li, Y; Romagnoli, G; Verlaat, B
2013-01-01
The extreme radiation dose received by vertex detectors at the Large Hadron Collider dictates stringent requirements on their cooling systems. To be robust against radiation damage, sensors should be maintained below -20 degree C and at the same time, the considerable heat load generated in the readout chips and the sensors must be removed. Evaporative CO2 cooling using microchannels etched in a silicon plane in thermal contact with the readout chips is an attractive option. In this paper, we present the first results of microchannel prototypes with circulating, two-phase CO2 and compare them to simulations. We also discuss a practical design of upgraded VELO detector for the LHCb experiment employing this approach.
Heavy Flavor Tracker (HFT): The new silicon vertex detector for the STAR experiment at RHIC
Energy Technology Data Exchange (ETDEWEB)
Margetis, Spiros [Kent State University, Ohio (United States)
2011-01-15
The HFT is the vertex-detector upgrade for the STAR experiment at RHIC. It is replacing the decommissioned silicon drift detector (SVT) with active pixel technology close to the beam pipe in order to increase by about an order of magnitude the track-pointing (DCA) resolution. This will allow direct and full topological reconstruction of charmed meson decays (e.g. D{sup 0}) and a better determination of the B-meson spectra. Key measurements include D{sup 0} elliptic flow (v{sub 2}) determination, especially in the lower transverse momenta (p{sub T}) region, and identified heavy quark suppression studies at high p{sub T} via the nuclear modification factor (R{sub CP} and R{sub AA}).
Heavy Flavor Tracker (HFT): The new silicon vertex detector for the STAR experiment at RHIC
International Nuclear Information System (INIS)
The HFT is the vertex-detector upgrade for the STAR experiment at RHIC. It is replacing the decommissioned silicon drift detector (SVT) with active pixel technology close to the beam pipe in order to increase by about an order of magnitude the track-pointing (DCA) resolution. This will allow direct and full topological reconstruction of charmed meson decays (e.g. D0) and a better determination of the B-meson spectra. Key measurements include D0 elliptic flow (v2) determination, especially in the lower transverse momenta (pT) region, and identified heavy quark suppression studies at high pT via the nuclear modification factor (RCP and RAA).
Heavy Flavor Tracker (HFT): The new silicon vertex detector for the STAR experiment at RHIC
Margetis, Spiros; STAR Collaboration
2011-01-01
The HFT is the vertex-detector upgrade for the STAR experiment at RHIC. It is replacing the decommissioned silicon drift detector (SVT) with active pixel technology close to the beam pipe in order to increase by about an order of magnitude the track-pointing (DCA) resolution. This will allow direct and full topological reconstruction of charmed meson decays (e.g. D 0) and a better determination of the B-meson spectra. Key measurements include D 0 elliptic flow (v 2) determination, especially in the lower transverse momenta ( pT) region, and identified heavy quark suppression studies at high pT via the nuclear modification factor ( R and R).
Test stand for the silicon vertex detector of the Collider Detector Facility
International Nuclear Information System (INIS)
A test stand for the next generation of the Silicon Vertex Detector (SVX-II) of the Collider Detector Facility (CDF) at Fermilab has been developed. It is capable of performing cosmic ray, beam, and laser pulsing tests on silicon strip detectors using the new generation of SVX chips. The test stand is composed of a SGI workstation, a VME CPU, the Silicon Test Acquisition and Readout (STAR) board, the Test Fiber Interface Board (TFIB), and the Test Port Card (TPC). The STAR mediates between external stimuli for the different tests and produces appropriate high level commands which are sent to the TFIB. The TFIB, in conjunction with the TPC, translates these commands into the correct logic levels to control the SVX chips. The four modes of operation of the SVX chips are configuration, data acquisition, digitization, and data readout. The data read out from the SVX chips is transferred to the STAR. The STAR can then be accessed by the VME CPU and the SGI workstation for future analysis. The detailed description of this test stand is given
Design optimisation for the silicon micro-strip part of the PANDA Micro-Vertex-Detector
International Nuclear Information System (INIS)
The PANDA experiment is one of the key projects at the future FAIR facility, which is under construction at GSI, Darmstadt. The Micro- Vertex-Detector (MVD) is the innermost detector part of the experiment. Silicon sensors are used for high precision tracking. The outer detector layers are equipped with double-sided silicon strip detectors. An optimisation has been accomplished for the layout of the MVD starting with the extraction of design parameters to qualify the physics performance of the detector. A clear definition of the requirements for the frontend electronics, and a precise description of the detector modules, the cooling system and the support structure are necessary to obtain realistic values concerning the material budget, the thermal load and space requirements. Altogether, this data can be taken as input for physics and engineering simulations. In parallel, prototypes for the detector modules and support structures are under development allowing the measurement of key parameters and the demonstration of the technical feasibility for the proposed concept. In consequence, the optimization process to be illustrated for the silicon micro-strip part of the MVD is based on both simulation results and experimental data.
Design and Tests of the Silicon Sensors for the ZEUS Micro Vertex Detector
Dannheim, D; Coldewey, C; Fretwurst, E; Garfagnini, A; Klanner, Robert; Martens, J; Koffeman, E; Tiecke, H G; Carlin, R
2003-01-01
To fully exploit the HERA-II upgrade,the ZEUS experiment has installed a Micro Vertex Detector (MVD) using n-type, single-sided, silicon micro-strip sensors with capacitive charge division. The sensors have a readout pitch of 120 micrometers, with five intermediate strips (20 micrometer strip pitch). The designs of the silicon sensors and of the test structures used to verify the technological parameters, are presented. Results on the electrical measurements are discussed. A total of 1123 sensors with three different geometries have been produced by Hamamatsu Photonics K.K. Irradiation tests with reactor neutrons and Co-60 photons have been performed for a small sample of sensors. The results on neutron irradiation (with a fluence of 1 x 10^{13} 1 MeV equivalent neutrons / cm^2) are well described by empirical formulae for bulk damage. The Co-60 photons (with doses up to 2.9 kGy) show the presence of generation currents in the SiO_2-Si interface, a large shift of the flatband voltage and a decrease of the hol...
Design and tests of the silicon sensors for the ZEUS Micro Vertex Detector
International Nuclear Information System (INIS)
To fully exploit the HERA-II upgrade, the ZEUS experiment has installed a micro vertex detector (MVD) using n-type, single-sided, silicon μ-strip sensors with capacitive charge division. The sensors have a readout pitch of 120 μm, with five intermediate strips (20 μm strip pitch). The designs of the silicon sensors and of the test structures used to verify the technological parameters, are presented. Results on the electrical measurements are discussed. A total of 1123 sensors with three different geometries have been produced by Hamamatsu Photonics K.K. Irradiation tests with reactor neutrons and 60Co photons have been performed for a small sample of sensors. The results on neutron irradiation (with a fluence of 1 . 1013 1 MeV equivalent neutrons / cm2) are well described by empirical formulae for bulk damage. The 60Co photons (with doses up to 2.9 kGy) show the presence of generation currents in the SiO2-Si interface, a large shift of the flatband voltage and a decrease of the hole mobility. (orig.)
Performance And Operation of the BaBar Calorimeter
International Nuclear Information System (INIS)
The performance and operation of the CsI(Tl) crystal calorimeter of the BABAR detector during the last years of operation is discussed. The BABAR detector is located at the PEP-II B Factory at the Stanford Linear Accelerator Center (SLAC). PEP-II is an asymmetric e+e--collider operating mainly at a center-of-mass energy of 10.58 GeV. This corresponds to the mass of the Υ(4S) resonance, which decays exclusively into B0(bar B)0 and B+B- pairs. One main physics goal of the BABAR experiment was the measurement of CP-violating asymmetries in the decay of neutral B-mesons. Other goals of the experiment include precision measurements of the decays of bottom mesons to charm and τ leptons, as well as searches for rare decays utilizing the high luminosity delivered by the PEP-II accelerator. The BABAR detector (Fig 1) consists of 6 subdetectors. Starting from the interaction point and moving radially outwards there is a Silicon Vertex Detector, Drift Chamber, DRC (Cherenkov detector), an Electromagnetic Calorimeter, and an Instrumented Flux Return.
Energy Technology Data Exchange (ETDEWEB)
Tanaka, M. (National Lab. for High Energy Physics, Ibaraki (Japan)); Ikeda, H. (National Lab. for High Energy Physics, Ibaraki (Japan)); Ikeda, M. (National Lab. for High Energy Physics, Ibaraki (Japan)); Inaba, S. (National Lab. for High Energy Physics, Ibaraki (Japan)); Fujita, Y. (National Lab. for High Energy Physics, Ibaraki (Japan)); Ozaki, H. (National Lab. for High Energy Physics, Ibaraki (Japan)); Matsuda, T. (National Lab. for High Energy Physics, Ibaraki (Japan)); Tsuboyama, T. (National Lab. for High Energy Physics, Ibaraki (Japan)); Fukunaga, C. (Tokyo Metropolitan Univ. (Japan)); Avrillon, S. (Graduate Univ. for Advanced Studies, Ibaraki (Japan)); Okuno, S. (Graduate Univ. for Advanced Studies, Ibaraki (Japan)); Haba, J. (Osaka Univ. (Japan)); Hanai, H. (Osaka Univ. (Japan)); Mori, S. (Tsukuba Univ., Ibaraki (Japan)); Yusa, K. (Tsukuba Univ., Ibaraki (Japan)); Korhonen, T. (Research Inst. for High Energy Physics (SEFT), Helsinki (Finland))
1994-03-15
We are developing the data-acquisition system of a silicon micro-vertex detector (SMVD) for the KEK B-factory. This data-acquisition system for the SMVD comprises detector modules, data scanners, and an event builder. We have developed several specially designed analog and digital VLSIs for the SMVD data-acquisition system. In this paper, we describe the system configuration together with the functions of the VLSIs. (orig.)
International Nuclear Information System (INIS)
We are developing the data-acquisition system of a silicon micro-vertex detector (SMVD) for the KEK B-factory. This data-acquisition system for the SMVD comprises detector modules, data scanners, and an event builder. We have developed several specially designed analog and digital VLSIs for the SMVD data-acquisition system. In this paper, we describe the system configuration together with the functions of the VLSIs. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Labarga, L.; Adolphsen, C.; Gratta, G.; Litke, A.; Turala, M.; Zaccardelli, C. (California Univ., Santa Cruz, CA (USA). Inst. for Particle Physics); Breakstone, A.; Parker, S. (Hawaii Univ., Honolulu, HI (USA)); Barnett, B.; Dauncey, P.; Drewer, D.; Matthews, J. (Johns Hopkins Univ., Baltimore, MD (USA)); Jacobsen, R.; Lueth, V. (Stanford Linear Accelerator Center, Menlo Park, CA (USA))
1989-12-01
A Silicon Strip Vertex Detector (SSVD) consisting of 36 independent silicon detector modules has been built for use in the Mark II detector at the SLAC Linear Collider (SLC). We discuss the performance of the individual modules and the stability and accuracy of their placement in the mechanical support. To gain operational experience at the SLC, we have assembled and placed inside the Mark II a telescope made of three Silicon Detector Modules. We present results from the first data run of the SLC on the overall performance of the Telescope, including backgrounds, charged particle tracking and spatial resolution. 7 refs., 10 figs.
Advances in the development of pixel detector for the SuperB Silicon Vertex Tracker
International Nuclear Information System (INIS)
The latest advances in the design and characterization of several pixel sensors developed to satisfy the very demanding requirements of the innermost layer of the SuperB Silicon Vertex Tracker will be presented in this paper. The SuperB machine is an electron positron collider operating at the ϒ(4S) peak to be built in the very near future by the Cabibbo Lab consortium. A pixel detector based on extremely thin, radiation hard devices able to cope with rate in the tens of MHz/cm2 range will be the optimal solution for the upgrade of the inner layer of the SuperB tracking system. At present several options with different levels of maturity are being investigated to understand advantages and potential issues of the different technologies: thin hybrid pixels, Deep N-Well CMOS MAPS, INMAPS CMOS MAPS featuring a quadruple well and high resistivity substrates and CMOS MAPS realized with Vertical Integration technology. The newest results from beam test, the outcomes of the radiation damage studies and the laboratory characterization of the latest prototypes will be reported
PROPOSAL FOR A SILICON VERTEX TRACKER (VTX) FOR THE PHENIX EXPERIMENT
Energy Technology Data Exchange (ETDEWEB)
AKIBA,Y.
2004-10-01
We propose the construction of a Silicon Vertex Tracker (VTX) for the PHENIX experiment at RHIC. The VTX will substantially enhance the physics capabilities of the PHENIX central arm spectrometers. Our prime motivation is to provide precision measurements of heavy-quark production (charm and beauty) in A+A, p(d)+A, and polarized p+p collisions. These are key measurements for the future RHIC program, both for the heavy ion program as it moves from the discovery phase towards detailed investigation of the properties of the dense nuclear medium created in heavy ion collisions, and for the exploration of the nucleon spin-structure functions. In addition, the VTX will also considerably improve other measurements with PHENIX. The main physics topics addressed by the VTX are: (1) Hot and dense strongly interacting matter--(a) Potential enhancement of charm production, (b) Open beauty production, (c) Flavor dependence of jet quenching and QCD energy loss, (d) Accurate charm reference for quarkonium, (e) Thermal dilepton radiation, (f) High p{sub T} phenomena with light flavors above 10-15 GeV/c in p{sub T}, and (g) Upsilon spectroscopy in the e{sup +}e{sup -} decay channel. (2) Gluon spin structure of the nucleon--(a) {Delta}G/G with charm, (b) {Delta}G/G with beauty, and (c) x dependence of {Delta}G/G with {gamma}-jet correlations. (3) Nucleon structure in nuclei--Gluon shadowing over broad x-range.
International Nuclear Information System (INIS)
The Bottom Collider Detector (BCD) has been proposed as a device to study large numbers of events containing B mesons. To identify secondary vertices in hadronic events it will employ the most ambitious silicon strip tracking detector proposed to-date. This report will discuss results from measurements on a first mechanical/thermal model of the vertex detector support structure. The model that was built and used for the studies described here is made of brass. Brass was used because it is readily available and easily assembled by soft soldering, and, for appropriate thicknesses, it will behave similarly to the beryllium that will be used in the actual detector. The trough was built to full scale with the reinforcement webbing and the cooling channels in place. There were no detector modules in place. We plan, however, to install modules in the trough in the future. The purpose of the model was to address two concerns that have arisen about the proposed structure of the detector. The first is whether or not the trough will be stable enough. The trough must be very light in weight yet have a high degree of rigidity. Because of the 3m length of the detector there is question as to the stiffness of the proposed trough. The main concern is that there will sagging or movement of the trough in the middle region. The second problem is the heat load. There will be a great deal of heat generated by the electronics attached to the detector modules. So the question arises as to whether or not the silicon detectors can be kept cool enough so that when the actual experiment is run the readings will be valid. The heat may also induce motion by differential expansion of support components. 26 figs
PROPOSAL FOR A SILICON VERTEX TRACKER (VTX) FOR THE PHENIX EXPERIMENT.
Energy Technology Data Exchange (ETDEWEB)
AKIBA,Y.
2004-03-30
We propose the construction of a Silicon Vertex Tracker (VTX) for the PHENIX experiment at RHIC. The VTX will substantially enhance the physics capabilities of the PHENIX central arm spectrometers. Our prime motivation is to provide precision measurements of heavy-quark production (charm and beauty) in A+A, p(d)+A, and polarized p+p collisions. These are key measurements for the future RHIC program, both for the heavy ion program as it moves from the discovery phase towards detailed investigation of the properties of the dense nuclear medium created in heavy ion collisions, and for the exploration of the nucleon spin-structure functions. In addition, the VTX will also considerably improve other measurements with PHENIX. The main physics topics addressed by the VTX are: (1) Hot and dense strongly interacting matter--Potential enhancement of charm production; Open beauty production; Flavor dependence of jet quenching and QCD energy loss; Accurate charm reference for quarkonium; Thermal dilepton radiation; High p{sub T} phenomena with light flavors above 10-15 GeV/c in p{sub T}; and Upsilon spectroscopy in the e{sup +}e{sup -} decay channel. (2) Gluon spin structure of the nucleon--{Delta}G/G with charm; {Delta}G/G with beauty; and x dependence of {Delta}G/G with {gamma}-jet correlations. (3) Nucleon structure in nuclei--Gluon shadowing over broad x-range. With the present PHENIX detector, heavy-quark production has been measured indirectly through the observation of single electrons. These measurements are inherently limited in accuracy by systematic uncertainties resulting from the large electron background from Dalitz decays and photon conversions. In particular, the statistical nature of the analysis does not allow for a model-independent separation of the charm and beauty contributions. The VTX detector will provide vertex tracking with a resolution of <50 {micro}m over a large coverage both in rapidity (|{eta}| < 1.2) and in azimuthal angle ({Delta}{phi} {approx
The Silicon Vertex Detector for b-tagging at Belle II
International Nuclear Information System (INIS)
The Belle experiment at KEK (Tsukuba, Japan) was successfully operated from 1999 until 2010 and confirmed the theoretical predictions of CP violation. In order to increase the beam intensity, a major upgrade of the KEKB collider is foreseen until 2015. The final goal is to reach a luminosity of 8 x 1035 cm-2 s-1, which is about 40 times higher than the previous peak value. This also implies changes to the Belle detector and its innermost tracking subdetector, the SVD (Silicon Vertex Detector), in particular. The SVD will be completely replaced, as it had already operated close to its limits in the past. All other subsystems will also be upgraded. This leads to the new Belle II experiment. The aim of Belle II is to search for deviations from the Standard Model of particle physics by providing extremely precise measurements of rare particle decays, thus representing a complementary approach to the direct searches performed at high energy hadron colliders. The upgraded SuperKEKB machine will collide electrons and positrons at the center-of-mass energy of excited states of the Y-particle, which hereafter decays to a B meson and its anti-particle. The decay vertices of these mesons have to be precisely measured by the Belle II SVD, together with the PXD (PiXel Detector) and the CDC (Central Drift Chamber). This allows the measurement of time-dependent, mixing-induced CP asymmetry. In addition, the SVD measures vertex information in other decay channels involving D meson and tau lepton decays. Since the collision energy is quite low (around 10 GeV), the emerging particles have low momentum and are subject to strong multiple scattering when traversing material. Therefore, all sensors of the Belle II SVD have to be optimised in terms of material thickness, while preserving high signal yield and position measurement accuracy. This will be possible by the development of thin, double-sided silicon microstrip sensors. This PhD thesis includes the physics motivation for
Production of high energy η' in B meson decays from BaBar experiment
International Nuclear Information System (INIS)
The work presented in this thesis relies on the analysis of data collected between october 1999 and July 2002 by the BaBar experiment at the PEP-II collider located at SLAC (Stanford, California). Electron-positron collisions at a center of mass energy equal to the Υ(4S) resonance mass are used for the production of B meson pairs. In July 2001, the BaBar collaboration published the first measurement of CP violation in the neutral B mesons system. Since then, the precision of the measurement has been continually being improved with the increasing data sample. Two devices are dedicated to the reconstruction of charged particles: the Silicon Vertex Tracker and the Drift Chamber. The Silicon Vertex Tracker is crucial for the reconstruction of the B meson decay vertex. Its motion with regard to the Drift Chamber needs a rolling calibration of the corresponding alignment parameters roughly every two hours. The relation between the Drift Chamber geometry and the alignment has been studied. Beside CP violation, Heavy Flavour Physics is an other important issue of BaBar research program. Rare decays are of particular interest as they are sensible to a new physics beyond the Standard Model. The production of high energy η' in B decays has been studied through the two main contributions, B→ η' Xs coming from the rare decay b → sg*, and B-bar0 → η'D0 coming from the internal tree color suppressed decay b → cud. The improvement of the measurement of the process B → η'X-s and the first. observation of the decay B-bar0 → η'D0 have led to the conclusion that the η' production is dominated by the decay b → sg* and enables to constrain its quark content. (author)
Recent progress in sensor- and mechanics-R and D for the Belle II Silicon Vertex Detector
Energy Technology Data Exchange (ETDEWEB)
Bergauer, T., E-mail: thomas.bergauer@oeaw.ac.at [Institute of High Energy Physics, Nikolsdorfer Gasse 18, A-1050 Vienna (Austria); Doljeschi, P.; Frankenberger, A.; Friedl, M.; Gfall, I.; Irmler, C. [Institute of High Energy Physics, Nikolsdorfer Gasse 18, A-1050 Vienna (Austria); Onuki, Y. [University of Tokyo, Department of Physics, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Smiljic, D. [Institute of High Energy Physics, Nikolsdorfer Gasse 18, A-1050 Vienna (Austria); Tsuboyama, T. [KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Valentan, M. [Institute of High Energy Physics, Nikolsdorfer Gasse 18, A-1050 Vienna (Austria)
2013-08-01
The Belle experiment at the KEKB electron/positron collider in Tsukuba (Japan) was successfully running for more than ten years. A major update of the machine to SuperKEKB is now foreseen until 2015, aiming a peak luminosity which is 40 times the peak value of the previous system. This also requires a redesign of the Belle detector (leading to Belle II) and especially its Silicon Vertex Detector (SVD), which surrounds the beam pipe. The future Belle II SVD will consist of four layers of double-sided silicon strip sensors based on 6 in. silicon wafers. Three of the four layers will be equipped with trapezoidal sensors in the slanted forward region. Moreover, two inner layers with pixel detectors based on DEPFET technology will complement the SVD as innermost detector. Since the KEKB-factory operates at relatively low energy, material inside the active volume has to be minimized in order to reduce multiple scattering. This can be achieved by arranging the sensors in the so-called “Origami chip-on-sensor concept”, and a very light-weight mechanical support structure made from carbon fiber reinforced Airex foam. Moreover, CO{sub 2} cooling for the front-end chips will ensure high efficiency at minimum material budget. In this paper, an overview of the future Belle II SVD design will be given, covering the silicon sensors, the readout electronics and the mechanics. A strong emphasis will be given to our R and D work on double-sided sensors where different p-stop layouts for the n-side of the detectors were compared. Moreover, this paper gives updated numbers for the mechanical dimensions of the ladders and their radii.
Beam Test of Silicon Strip Sensors for the ZEUS Micro Vertex Detector
Bauerdick, L A T; Burgard, C; Carli, T; Carlin, R; Casaro, M; Chiochia, V; Corso, F D; Dannheim, D; Garfagnini, A; Kappes, A; Klanner, Robert; Koffeman, E; Koppitz, B; Kötz, U; Maddox, E; Milite, M; Moritz, M; Ng, J S T; Petrucci, M C; Redondo, I; Rautenberg, J; Tiecke, H G; Turcato, M; Velthuis, J J; Weber, A
2003-01-01
For the HERA upgrade, the ZEUS experiment has designed and installed a high precision Micro Vertex Detector (MVD) using single sided micro-strip sensors with capacitive charge division. The sensors have a readout pitch of 120 microns, with five intermediate strips (20 micron strip pitch). An extensive test program has been carried out at the DESY-II testbeam facility. In this paper we describe the setup developed to test the ZEUS MVD sensors and the results obtained on both irradiated and non-irradiated single sided micro-strip detectors with rectangular and trapezoidal geometries. The performances of the sensors coupled to the readout electronics (HELIX chip, version 2.2) have been studied in detail, achieving a good description by a Monte Carlo simulation. Measurements of the position resolution as a function of the angle of incidence are presented, focusing in particular on the comparison between standard and newly developed reconstruction algorithms.
CATS a cellular automaton for tracking in silicon for the HERA-B vertex detector
Abt, I; Kisel, I; Masciocchi, S
2002-01-01
The new track reconstruction program CATS developed for the Vertex Detector System of the HERA-B experiment at DESY is presented. It employs a cellular automaton for track searching and the Kalman filter for track fitting. This results in a very fast algorithm that combines highly efficient track recognition with accurate and reliable track parameter estimation. To reduce the computational cost of the fit an optimized numerical implementation of the Kalman filter is used. Alternative approaches to the track reconstruction in the VDS are also discussed. Since 1999, after extensive tests on simulated data, CATS has been employed to reconstruct experimental data collected in HERA-B. Results regarding tracking performance, the accuracy of track parameter estimates and CPU time consumption are presented.
CATS: a cellular automaton for tracking in silicon for the HERA-B vertex detector
International Nuclear Information System (INIS)
The new track reconstruction program CATS developed for the Vertex Detector System of the HERA-B experiment at DESY is presented. It employs a cellular automaton for track searching and the Kalman filter for track fitting. This results in a very fast algorithm that combines highly efficient track recognition with accurate and reliable track parameter estimation. To reduce the computational cost of the fit an optimized numerical implementation of the Kalman filter is used. Alternative approaches to the track reconstruction in the VDS are also discussed. Since 1999, after extensive tests on simulated data, CATS has been employed to reconstruct experimental data collected in HERA-B. Results regarding tracking performance, the accuracy of track parameter estimates and CPU time consumption are presented
BaBar: a new detector for the study of CP violation in the system of B mesons
International Nuclear Information System (INIS)
The technical conception report of the new BaBar detector has been accepted by the SLAC (Stanford Linear Accelerator Center) experiments program committee. The new detector will be operational in 1999, about six month after the starting of the new collider. The aim of the BaBar detector is to observe the CP violation in the mesons B system for a large variety of disintegration modes. Disintegration of B mesons involves J/psi, kaons, pairs of D mesons and light mesons particles and would allow the measurement of crucial parameters linked to the Cabbibo-Kobayashi-Maskawa matrix. The detector comprises: a double-side silicon vertex detector, a drift chamber with 40 layers of wires in a 1.5 T magnetic induction, a shower counter with 6800 cesium iodide crystals and Cherenkov counters. (J.S.). 2 figs
International Nuclear Information System (INIS)
In this thesis, we were interested in fully reconstructed charmed events, using the results from NA14/2 experiment at CERN. A filtering program, using the active target information, have been developed. D+ and D0 lifetimes have been measured using samples of events with a very good signal to noise ratio. We find values in good agreement with previous experimental results. In addition, the study of the silicon recoil nucleus in the detector enables us, to set a limit on the coherent charm photoproduction cross section
Operational Experience, Improvements, and Performance of the CDF Run II Silicon Vertex Detector
Aaltonen, T; Boveia, A.; Brau, B.; Bolla, G; Bortoletto, D; Calancha, C; Carron, S.; Cihangir, S.; Corbo, M.; Clark, D.; Di Ruzza, B.; Eusebi, R.; Fernandez, J.P.; Freeman, J.C.; Garcia, J.E.; Garcia-Sciveres, M.; Gonzalez, O.; Grinstein, S.; Hartz, M.; Herndon, M.; Hill, C.; Hocker, A.; Husemann, U.; Incandela, J.; Issever, C.; Jindariani, S.; Junk, T.R.; Knoepfel, K.; Lewis, J.D.; Martinez-Ballarin, R.; Mathis, M.; Mattson, M.; Merkel, P; Mondragon, M.N.; Moore, R.; Mumford, J.R.; Nahn, S.; Nielsen, J.; Nelson, T.K.; Pavlicek, V.; Pursley, J.; Redondo, I.; Roser, R.; Schultz, K.; Spalding, J.; Stancari, M.; Stanitzki, M.; Stuart, D.; Sukhanov, A.; Tesarek, R.; Treptow, K.; Wallny, R.; Worm, S.
2013-01-01
The Collider Detector at Fermilab (CDF) pursues a broad physics program at Fermilab's Tevatron collider. Between Run II commissioning in early 2001 and the end of operations in September 2011, the Tevatron delivered 12 fb-1 of integrated luminosity of p-pbar collisions at sqrt(s)=1.96 TeV. Many physics analyses undertaken by CDF require heavy flavor tagging with large charged particle tracking acceptance. To realize these goals, in 2001 CDF installed eight layers of silicon microstrip detectors around its interaction region. These detectors were designed for 2--5 years of operation, radiation doses up to 2 Mrad (0.02 Gy), and were expected to be replaced in 2004. The sensors were not replaced, and the Tevatron run was extended for several years beyond its design, exposing the sensors and electronics to much higher radiation doses than anticipated. In this paper we describe the operational challenges encountered over the past 10 years of running the CDF silicon detectors, the preventive measures undertaken, an...
Measurement of D0 lifetime with the BaBar detector
Energy Technology Data Exchange (ETDEWEB)
Simi, Gabriele; /Pisa U. /SLAC
2009-12-17
This work is the result of the researchers carried out during a three years Ph.D. period in the BABAR experiment. The first chapter consists in an introduction to the theoretical aspects of the D{sup 0} meson lifetime determination and CP violation parameters, as well as an overview of the CP violation in the B sector, which is the main topic of the experiment. The description of the experimental apparatus follows with particular attention to the Silicon Vertex Tracker detector, the most critical detector for the determination of decay vertices and thus of lifetimes and time dependent CP violation asymmetries. In the fourth chapter the operation and running of the vertex detector is described, as a result from the experience as Operation Manager of the SVT, with particular attention to the safety of the device and the data quality assurance. The last chapter is dedicated to the determination of the D{sup 0} meson lifetime with the BABAR detector, which is the main data analysis carried out by the candidate. The analysis is characterized by the selection of an extremely pure sample of D{sup 0} mesons for which the decay flight length and proper time is reconstructed. The description of the unbinned maximum likelihood fit follows, as well as the discussion of the possible sources of systematic uncertainties. In the appendix is also presented a preliminary study of a possible development regarding the determination of mixing and CP violation parameters for the D{sup 0} meson.
Silicon Vertex Tracker for PHENIX Upgrade at RHIC: Capabilities and Detector Technology
Nouicer, Rachid
2008-01-01
From the wealth of data obtained from the first three years of RHIC operation, the four RHIC experiments, BRAHMS, PHENIX, PHOBOS and STAR, have concluded that a high density partonic matter is formed at central Au+Au collisions at \\sqrt{s_{NN}} = 200 GeV. The research focus now shifts from initial discovery to a detailed exploration of partonic matter. Particles carrying heavy flavor, i.e. charm or beauty quarks, are powerful tool for study the properties of the hot and dense medium created in high-energy nuclear collisions at RHIC. They also allow to probe the spin structure of the proton in a new and precise way. An upgrade of RHIC (RHIC-II) is intended for the second half of the decade, with a luminosity increase to about 20-40 times the design value of 8 x 10^26 cm^-2 s^-1 for Au+Au, and 2 x 10^32 cm^-2 s^-1 for polarized proton beams. The PHENIX collaboration plans to upgrade its experiment to exploit with an enhanced detector new physics then in reach. For this purpose, we are constructing the Silicon V...
International Nuclear Information System (INIS)
The work presented in this thesis has contributed to the development of the Compact Muon Solenoid detector (CMS) that will be installed at the future Large Hadron Collider (LHC) which will start running in summer 2007. This report is organised in three parts: the study of gaseous detectors and silicon micro-strips detectors, and a development of a software for the reconstruction and analysis of CMS data in the framework of ORCA. First, the micro-strips gaseous detectors (MSGC) study was on the ultimate critical irradiation test before their substitution in the CMS tracker. This test showed a really small number of lost anodes and a stable signal to noise ratio. This test proved that the described MSGC fulfill all the requirements to be integrated in the CMS tracker. The following contribution described a study of silicon micro-strips detectors and its electronics exposed to a 40 MHz bunched LHC like beam. These tests indicated a good behaviour of the data acquisition and control system. The signal to noise ratio, the bunch crossing identification and the cluster finding efficiency had also be analysed. The last study concern the design and the development of an ORCA algorithm dedicates to secondary vertex reconstruction. This iterative algorithm aims to be use for b tagging. This part analyse also primary vertex reconstruction in events without and with pile up. (author)
Energy Technology Data Exchange (ETDEWEB)
Hicheur, A
2003-04-01
The work presented in this thesis relies on the analysis of data collected between october 1999 and July 2002 by the BaBar experiment at the PEP-II collider located at SLAC (Stanford, California). Electron-positron collisions at a center of mass energy equal to the {upsilon}(4S) resonance mass are used for the production of B meson pairs. In July 2001, the BaBar collaboration published the first measurement of CP violation in the neutral B mesons system. Since then, the precision of the measurement has been continually being improved with the increasing data sample. Two devices are dedicated to the reconstruction of charged particles: the Silicon Vertex Tracker and the Drift Chamber. The Silicon Vertex Tracker is crucial for the reconstruction of the B meson decay vertex. Its motion with regard to the Drift Chamber needs a rolling calibration of the corresponding alignment parameters roughly every two hours. The relation between the Drift Chamber geometry and the alignment has been studied. Beside CP violation, Heavy Flavour Physics is an other important issue of BaBar research program. Rare decays are of particular interest as they are sensible to a new physics beyond the Standard Model. The production of high energy {eta}' in B decays has been studied through the two main contributions, B{yields} {eta}' X{sub s} coming from the rare decay b {yields} sg*, and B-bar{sup 0} {yields} {eta}'D{sup 0} coming from the internal tree color suppressed decay b {yields} cud. The improvement of the measurement of the process B {yields} {eta}'X-s and the first. observation of the decay B-bar{sup 0} {yields} {eta}'D{sup 0} have led to the conclusion that the {eta}' production is dominated by the decay b {yields} sg* and enables to constrain its quark content. (author)
Eklund, L
2004-01-01
LHCb is an experiment at the Large Hadron Collider (LHC), dedicated to the study of b-hadron physics. The Vertex Locator (VELO) is a sub-detector which reconstructs primary and secondary vertices, which is of importance for the processes under study. It is a silicon micro-strip detector operated in a harsh radiation environment with demands of high read-out speed and the use of minimal material. In this paper, the LHCb VELO is introduced and the technology choices of the detector are motivated. We report on the present status of the project and one possible upgrade technology is presented.
Li, Haisheng; Tan, Shaobin; Wang, Qing
2012-01-01
In this paper, we study a notion of what we call vertex Leibniz algebra. This notion naturally extends that of vertex algebra without vacuum, which was previously introduced by Huang and Lepowsky. We show that every vertex algebra without vacuum can be naturally extended to a vertex algebra. On the other hand, we show that a vertex Leibniz algebra can be embedded into a vertex algebra if and only if it admits a faithful module. To each vertex Leibniz algebra we associate a vertex algebra with...
Di Pietro, V.; Brinkmann, K.-Th.; Riccardi, A.; Ritman, J.; Rivetti, A.; Rolo, M. D.; Stockmanns, T.; Zambanini, A.
2016-03-01
The bar PANDA (Antiproton Annihilation at Darmstadt) experiment foresees many detectors for tracking, particle identification and calorimetry. Among them, the innermost is the MVD (Micro Vertex Detector) responsible for a precise tracking and the reconstruction of secondary vertices. This detector will be built from both hybrid pixel (two inner barrels and six forward disks) and double-sided micro strip (two outer barrels and outer rim of the last two disks) silicon sensors. A time-based approach has been chosen for the readout ASIC of the strip sensors. The PASTA (bar PANDA Strip ASIC) chip aims at high resolution time-stamping and charge information through the Time over Threshold (ToT) technique. It benefits from a Time to Digital Converter (TDC) allowing a time bin width down to 50 ps. The analog front-end was designed to serve both n-type and p-type strips and the performed simulations show remarkable performances in terms of linearity and electronic noise. The TDC consists of an analog interpolator, a digital local controller, and a digital global controller as the common back-end for all of the 64 channels.
International Nuclear Information System (INIS)
The P-bar ANDA (Antiproton Annihilation at Darmstadt) experiment foresees many detectors for tracking, particle identification and calorimetry. Among them, the innermost is the MVD (Micro Vertex Detector) responsible for a precise tracking and the reconstruction of secondary vertices. This detector will be built from both hybrid pixel (two inner barrels and six forward disks) and double-sided micro strip (two outer barrels and outer rim of the last two disks) silicon sensors. A time-based approach has been chosen for the readout ASIC of the strip sensors. The PASTA ( P-bar ANDA Strip ASIC) chip aims at high resolution time-stamping and charge information through the Time over Threshold (ToT) technique. It benefits from a Time to Digital Converter (TDC) allowing a time bin width down to 50 ps. The analog front-end was designed to serve both n-type and p-type strips and the performed simulations show remarkable performances in terms of linearity and electronic noise. The TDC consists of an analog interpolator, a digital local controller, and a digital global controller as the common back-end for all of the 64 channels
Energy Technology Data Exchange (ETDEWEB)
Moreau, St
2002-12-01
The work presented in this thesis has contributed to the development of the Compact Muon Solenoid detector (CMS) that will be installed at the future Large Hadron Collider (LHC) which will start running in summer 2007. This report is organised in three parts: the study of gaseous detectors and silicon micro-strips detectors, and a development of a software for the reconstruction and analysis of CMS data in the framework of ORCA. First, the micro-strips gaseous detectors (MSGC) study was on the ultimate critical irradiation test before their substitution in the CMS tracker. This test showed a really small number of lost anodes and a stable signal to noise ratio. This test proved that the described MSGC fulfill all the requirements to be integrated in the CMS tracker. The following contribution described a study of silicon micro-strips detectors and its electronics exposed to a 40 MHz bunched LHC like beam. These tests indicated a good behaviour of the data acquisition and control system. The signal to noise ratio, the bunch crossing identification and the cluster finding efficiency had also be analysed. The last study concern the design and the development of an ORCA algorithm dedicates to secondary vertex reconstruction. This iterative algorithm aims to be use for b tagging. This part analyse also primary vertex reconstruction in events without and with pile up. (author)
Energy Technology Data Exchange (ETDEWEB)
Eigen, Gerald [University of Bergen, Bergen (Norway). Dept. of Physics
2015-04-29
We present herein the most recent BABAR results on direct CP asymmetry measurements in B → X_{s}γ, on partial branching fraction and CP asymmetry measurements in B → X_{s}ℓ^{+}ℓ^{-}, on a search for B → π/ηℓ^{+}ℓ^{-} decays, on a search for lepton number violation in B^{+} → X^{-}ℓ^{+}ℓ'^{+} modes and a study of B^{0} →ωω and B^{0} → ωφ decays.
Chabanat, E; D'Hondt, J; Vanlaer, P; Prokofiev, K; Speer, T; Frühwirth, R; Waltenberger, W
2005-01-01
Because of the high track multiplicity in the final states expected in proton collisions at the LHC experiments, novel vertex reconstruction algorithms are required. The vertex reconstruction problem can be decomposed into a pattern recognition problem ("vertex finding") and an estimation problem ("vertex fitting"). Starting from least-square methods, ways to render the classical algorithms more robust are discussed and the statistical properties of the novel methods are shown. A whole set of different approaches for the vertex finding problem is presented and compared in relevant physics channels.
Energy Technology Data Exchange (ETDEWEB)
Renga, Francesco
2008-09-30
We will present the most recent results from the BABAR Collaboration concerning New Physics searches in rare B and Lepton Flavour Violating (LFV) decays, including b {yields} s transitions, purely leptonic B decays and LFV {tau} decays.
Track finding efficiency in BABAR
International Nuclear Information System (INIS)
We describe several studies to measure the charged track reconstruction efficiency and asymmetry of the BABAR detector. The first two studies measure the tracking efficiency of a charged particle using τ and initial state radiation decays. The third uses the τ decays to study the asymmetry in tracking, the fourth measures the tracking efficiency for low momentum tracks, and the last measures the reconstruction efficiency of KS0 particles. The first section also examines the stability of the measurements vs. BABAR running periods
International Nuclear Information System (INIS)
This document describes the implementation of the topological vertex finding algorithm ZVTOP within the org.lcsim reconstruction and analysis framework. At the present date, Java vertexing tools allow users to perform topological vertexing on tracks that have been obtained from a Fast MC simulation. An implementation that will be able to handle fully reconstructed events is being designed from the ground up for longevity and maintainability
The refined topological vertex
International Nuclear Information System (INIS)
We define a refined topological vertex which depends in addition on a parameter, which physically corresponds to extending the self-dual graviphoton field strength to a more general configuration. Using this refined topological vertex we compute, using geometric engineering, a two-parameter (equivariant) instanton expansion of gauge theories which reproduce the results of Nekrasov. The refined vertex is also expected to be related to Khovanov knot invariants.
Menges, W
2006-01-01
Resistive Plate Chambers (RPCs) were used for the instrumentation of the iron flux return of the BABAR detector as a muon system. Unfortunately the efficiency of the original RPCs degraded rapidly with time. Limited Streamer Tubes (LSTs) were chosen for an upgrade of the barrel portion of the detector. The phased installation started in summer 2004 with replacing two sextants of the BABAR barrel muon system with LSTs. The modules for the remaining four sextants are under long-term test at SLAC and ready for installation, expected in 2006. The modules become inaccessible once installed in BABAR, so it is critical to select only perfectly working tubes. To accomplish this a strong QC system was established during the prototype phase, and fully implemented throughout pre-production and construction. To spot any damage during transport, the final modules are subjected to comprehensive tests at SLAC immediately after arrival and kept under long-term test till installation into BABAR. Details of these tests and res...
The design and performance of the ZEUS Micro Vertex detector
Brock, I; Kappes, A; Katz, U F; Hilger, E; Rautenberg, J; Weber, A; Mastroberardino, A; Tassi, E; Adler, V; Bauerdick, L A T; Bloch, I; Haas, T; Klein, U; Kötz, U; Kramberger, G; Lobodzinska, E; Mankel, R; Ng, J; Notz, D; Petrucci, M C; Surrow, B; Watt, G; Youngman, C; Zeuner, W; Coldewey, C; Heller, R; Gallo, E; Carli, T; Chiochia, V; Dannheim, D; Fretwurst, E; Garfagnini, A; Klanner, R; Koppitz, B; Martens, J; Milite, M; Tokushuku, K; Redondo, I; Boterenbrood, H; Koffeman, E; Kooijman, P; Maddox, E; Tiecke, H; Vázquez, M; Velthuis, J; Wiggers, L; Devenish, R C E; Dawson, M; Ferrando, J; Grzelak, G; Korcsak-Gorzo, K; Matsushita, T; Oliver, K; Shield, P; Walczak, R; Bertolin, A; Borsato, E; Carlin, R; Dal Corso, F; Longhin, A; Turcato, M; Fusayasu, T; Hori, R; Kohno, T; Shimizu, S; Larsen, H E; Sacchi, R; Staiano, A; Arneodo, M; Ruspa, M; Butterworth, J; Gwenlan, C; Fraser, J; Hayes, D; Hayes, M; Lane, J; Nixon, G; Postranecky, M; Sutton, M; Warren, M
2007-01-01
In order to extend the tracking acceptance, to improve the primary and secondary vertex reconstruction and thus enhancing the tagging capabilities for short lived particles, the ZEUS experiment at the HERA Collider at DESY installed a silicon strip vertex detector. The barrel part of the detector is a 63 cm long cylinder with silicon sensors arranged around an elliptical beampipe. The forward part consists of four circular shaped disks. In total just over 200k channels are read out using $2.9 {\\rm m^2}$ of silicon. In this report a detailed overview of the design and construction of the detector is given and the performance of the completed system is reviewed.
Performance of the ATLAS vertex detector
Barberis, D
1999-01-01
The ATLAS inner detector consists of three layers of silicon pixels, four double layers of silicon microstrips and a transition radiation tracker (straw tubes). The good performance of the track and vertex reconstruction algorithms is a direct consequence of the small radius (4.3, 10.1 and 13.2 cm), fine pitch (50*300 mu m) and low occupancy (<3*10/sup -4/ at design luminosity) of the pixel detectors. The full (GEANT3) detector simulation is used to evaluate the performance of the detector and of the reconstruction algorithms. Results are presented on track and vertex reconstruction efficiencies and resolutions, and on the separation between b-jets and jets produced by light quarks. (8 refs).
The Orbifold Topological Vertex
Bryan, Jim; Young, Ben
2010-01-01
We define Donaldson-Thomas invariants of Calabi-Yau orbifolds and we develop a topological vertex formalism for computing them. The basic combinatorial object is the orbifold vertex, a generating function for the number of 3D partitions asymptotic to three given 2D partitions and colored by representations of a finite Abelian group G acting on C^3. In the case where G=Z_n acting on C^3 with transverse A_{n-1} quotient singularities, we give an explicit formula for the vertex in terms of Schur functions. We discuss applications of our formalism to the Donaldson-Thomas Crepant Resolution Conjecture and to the orbifold Donaldson-Thomas/Gromov-Witten correspondence. We also explicitly compute the Donaldson-Thomas partition function for some simple orbifold geometries: the local football and the local BZ_2 gerbe.
Cohomological vertex operators
Viña, Andrés
2016-01-01
Given a Calabi-Yau manifold and considering the $B$-branes on it as objects in the derived category of coherent sheaves, we identify the vertex operators for strings between two branes with elements of the cohomology groups of Ext sheaves. We define the correlation functions for these general vertex operators. Strings stretching between two coherent sheaves are studied as homological extensions of the corresponding branes. In this context, we relate strings between different pairs of branes when there are maps between these branes. We also interpret some strings with ghost number $k$ as obstructions for lifts or extensions of strings with ghost number $k-1$.
The VELO (VErtex LOcator) at the LHCb experiment
De Capua, S.
2008-01-01
The LHCb silicon vertex locator (VELO) is an array of silicon planes installed in a retractable roman pot system, which will enable the LHCb experiment to reconstruct and trigger on b-hadrons produced in collisions at the LHC. The VELO will be also used to attempt measuring the absolute luminosity with a novel method based on vertex reconstruction of beam gas interactions. In this paper the VELO system, its construction and the results from the commissioning phase are presented. The options for a possible upgraded detector are also discussed.
DIRC, the particle identification system for BABAR
International Nuclear Information System (INIS)
The DIRC, a novel type of Cherenkov ring imaging device, is the primary hadronic particle identification system for the BABAR detector at the asymmetric B-factory, PEP-II at SLAC. BABAR began taking data with colliding beams mode in late spring 1999. This paper describes the performance of the DIRC during the first 16 months of operation. (author)
Scott, I; Grosso, P; Hamilton, R T; Huffer, M E; O'Grady, C; Russell, J J
1998-01-01
The BaBar experiment at the Stanford Linear Accelerator Center is designed to perform a search for CP violation by analysing the decays of a very large sample of B and Bbar mesons produced at the high luminosity PEP-11 accelerator. The data acquisition system must cope with a sustained high event rate, while supporting real time feature extraction and data compression with minimal dead time. The BaBar data acquisition system is based around a common VME interface to the electronics read-out of the separate detector subsystems. Data from the front end electronics is read into commercial VME processors via a custom "personality card" and PCI interface. The commercial CPUs run the Tornado operating system to provide a platform for detector subsystem code to perform the necessary data processing. The data are read out via a non-blocking network switch to a farm of commercial UNIX processors. Careful design of the core data acquisition code has enabled us to sustain events rates in excess of 20 kHz while maintaini...
Dannheim, D.
2015-03-01
The precision physics needs at TeV-scale linear electron-positron colliders (ILC and CLIC) require a vertex-detector system with excellent flavour-tagging capabilities through a measurement of displaced vertices. This is essential, for example, for an explicit measurement of the Higgs decays to pairs of b-quarks, c-quarks and gluons. Efficient identification of top quarks in the decay t → Wb will give access to the ttH-coupling measurement. In addition to those requirements driven by physics arguments, the CLIC bunch structure calls for hit timing at the few-ns level. As a result, the CLIC vertex-detector system needs to have excellent spatial resolution, full geometrical coverage extending to low polar angles, extremely low material budget, low occupancy facilitated by time-tagging, and sufficient heat removal from sensors and readout. These considerations challenge current technological limits. A detector concept based on hybrid pixel-detector technology is under development for the CLIC vertex detector. It comprises fast, low-power and small-pitch readout ASICs implemented in 65 nm CMOS technology (CLICpix) coupled to ultra-thin planar or active HV-CMOS sensors via low-mass interconnects. The power dissipation of the readout chips is reduced by means of power pulsing, allowing for a cooling system based on forced gas flow. This contribution reviews the requirements and design optimisation for the CLIC vertex detector and gives an overview of recent R&D achievements in the domains of sensors, readout and detector integration.
International Nuclear Information System (INIS)
A fast second level trigger has been developed for the ARGUS experiment which recognizes tracks originating from the interaction region. The processor compares the hits in the ARGUS Micro Vertex Drift Chamber to 245760 masks stored in random access memories. The masks which are fully defined in three dimensions are able to reject tracks originating in the wall of the narrow beampipe of 10.5 mm radius. (orig.)
International Nuclear Information System (INIS)
The precision physics needs at TeV-scale linear electron-positron colliders (ILC and CLIC) require a vertex-detector system with excellent flavour-tagging capabilities through a measurement of displaced vertices. This is essential, for example, for an explicit measurement of the Higgs decays to pairs of b-quarks, c-quarks and gluons. Efficient identification of top quarks in the decay t → Wb will give access to the ttH-coupling measurement. In addition to those requirements driven by physics arguments, the CLIC bunch structure calls for hit timing at the few-ns level. As a result, the CLIC vertex-detector system needs to have excellent spatial resolution, full geometrical coverage extending to low polar angles, extremely low material budget, low occupancy facilitated by time-tagging, and sufficient heat removal from sensors and readout. These considerations challenge current technological limits. A detector concept based on hybrid pixel-detector technology is under development for the CLIC vertex detector. It comprises fast, low-power and small-pitch readout ASICs implemented in 65 nm CMOS technology (CLICpix) coupled to ultra-thin planar or active HV-CMOS sensors via low-mass interconnects. The power dissipation of the readout chips is reduced by means of power pulsing, allowing for a cooling system based on forced gas flow. This contribution reviews the requirements and design optimisation for the CLIC vertex detector and gives an overview of recent R and D achievements in the domains of sensors, readout and detector integration
DEFF Research Database (Denmark)
Andersson, Per; Köpsén, Susanne; Gross, Marin;
This report presents the results from a comparative study of the qualification of adult educators in the Nordic-Baltic region. The study involved Denmark, Estonia and Sweden. The rationale behind the study is a growing interest in adult education resulting from a focus on lifelong learning in the...
EMC studies for the vertex detector of the Belle II experiment
International Nuclear Information System (INIS)
The upgrade of the Belle II experiment plans to use a vertex detector based on two different technologies, DEPFET pixel (PXD) technology and double side silicon microstrip (SVD) technology. The vertex electronics are characterized by the topology of SVD bias that forces to design a sophisticated grounding because of the floating power scheme. The complex topology of the PXD power cable bundle may introduce some noise inside the vertex area. This paper presents a general overview of the EMC issues present in the vertex system, based on EMC tests on an SVD prototype and a study of noise propagation in the PXD cable bundle based on Multi-conductor transmission line theory
Developments in solid state vertex detectors
International Nuclear Information System (INIS)
Since the discovery of the J/psi in November 1974, there has been a strong interest in the physics of particles containing higher-flavour quarks (charm, bottom, top, ...). High precision vertex detectors can be used to identify the decay products of parent particles which have lifetimes of the order 10-13 s. The paper surveys the progress which is being made in developing silicon detectors with the necessary tracking precision (< approx. 5 μm) to be used for this purpose in fixed target experiments and also in colliders such as SLC and LEP. (author)
Performance of the LHCb Vertex Locator
Latham, T
2012-01-01
LHCb is a dedicated flavour physics experiment at the Large Hadron Collider (LHC) at CERN. The Vertex Locator (VELO) is an essential part of the LHCb detector, permitting precision measurements of the production and decay vertices of beauty and charm particles. The VELO consists of a series of silicon micro-strip detectors, arranged in two retractable halves. Positioned only 7 mm from the beam during normal operations, it must withstand very high levels of radiation. The performance of the LHCb VELO during the first year of LHC physics running is presented.
International Nuclear Information System (INIS)
While linear estimators are optimal when the model is linear and all random noise is Gaussian, they are very sensitive to outlying tracks. Non-linear vertex reconstruction algorithms offer a higher degree of robustness against such outliers. Two of the algorithms presented, the Adaptive filter and the Trimmed Kalman Filter are able to down-weight or discard these outlying tracks, while a third, the Gaussian-sum filter, offers a better treatment of non-Gaussian distributions of track parameter errors when these are modelled by Gaussian mixtures
International Nuclear Information System (INIS)
A dedicated particle identification system based on the Detection of Internally Reflected Cherenkov (DIRC) light will be used in the BaBar detector. We provide an overview of the DIRC concept, design, and expected performance of the production device and a status report on its construction and commissioning. The DIRC is expected to be operating in the BaBar detector on beam line at the PEP-II B Factory in late spring 1999
Using Grid for the BABAR Experiment
International Nuclear Information System (INIS)
The BaBar experiment has been taking data since 1999. In 2001 the computing group started to evaluate the possibility to evolve toward a distributed computing model in a grid environment. We built a prototype system, based on the European Data Grid (EDG), to submit full-scale analysis and Monte Carlo simulation jobs. Computing elements, storage elements, and worker nodes have been installed at SLAC and at various European sites. A BaBar virtual organization (VO) and a test replica catalog (RC) are maintained in Manchester, U.K., and the experiment is using three EDG testbed resource brokers in the U.K. and in Italy. First analysis tests were performed under the assumption that a standard BaBar software release was available at the grid target sites, using RC to register information about the executable and the produced n-tuples. Hundreds of analysis jobs accessing either Objectivity or Root data files ran on the grid. We tested the Monte Carlo production using a farm of the INFN-grid testbed customized to install an Objectivity database and run BaBar simulation software. First simulation production tests were performed using standard Job Description Language commands and the output files were written on the closest storage element. A package that can be officially distributed to grid sites not specifically customized for BaBar has been prepared. We are studying the possibility to add a user friendly interface to access grid services for BaBar
Dannheim, D
2015-01-01
The precision physics needs at TeV-scale linear electron-positron colliders (ILC and CLIC) require a vertex-detector system with excellent flavour-tagging capabilities through a meas- urement of displaced vertices. This is essential, for example, for an explicit measurement of the Higgs decays to pairs of b-quarks, c-quarks and gluons. Efficient identification of top quarks in the decay t → W b will give access to the ttH-coupling measurement. In addition to those requirements driven by physics arguments, the CLIC bunch structure calls for hit tim- ing at the few-ns level. As a result, the CLIC vertex-detector system needs to have excellent spatial resolution, full geometrical coverage extending to low polar angles, extremely low material budget, low occupancy facilitated by time-tagging, and sufficient heat removal from sensors and readout. These considerations challenge current technological limits. A detector concept based on hybrid pixel-detector technology is under development for the CLIC ver- tex det...
Preliminary studies for the LHCb vertex detector vacuum system
Doets, M; Van Bakel, N; Van den Brand, J F J; van den Brand, Jo
2000-01-01
We lay down some general considerations which will serve as a starting point for design studies of a realistic LHCb vertex detector vacuum system. Based on these considerations, we propose a design strategy and identify issues to be further studied. In particular we try to outline some boundary conditions imposed by LHC and LHCb on the vacuum system. We discuss two possibilities for the LHCb vertex detector vacuum system. The preferred strategy uses a differentially pumped vacuum system with the silicon detectors separated from the beam line vacuum. Some estimations on static vacuum pressures and gas flows are presented.
First Results from the LHCb Vertex Locator
Borghi, S
2010-01-01
LHCb is a dedicated experiment to study new physics in the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. The beauty and charm hadrons are identified through their flight distance in the Vertex Locator (VELO), and hence the detector is critical for both the trigger and offline physics analyses. The VELO is the silicon detector surrounding the interaction point, and is the closest LHC vertex detector to the interaction point, located only 7 mm from the LHC beam during normal operation. The detector will operate in an extreme and highly non-uniform radiation environment. The VELO consists of two retractable detector halves with 21 silicon micro-strip tracking modules each. A module is composed of two n+-on-n 300 micron thick half disc sensors with R-measuring and Phi-measuring micro-strip geometry, mounted on a carbon fibre support paddle. The minimum pitch is approximately 40 $\\mu$m. The detector is also equipped with one n-on-p module. The detectors are operated in vacuum and a...
The design and performance of the ZEUS micro vertex detector
Energy Technology Data Exchange (ETDEWEB)
Polini, A. [Bologna Univ. (Italy)]|[INFN Bologna (Italy); Brock, I.; Goers, S. [Bonn Univ. (DE). Physikalisches Institut] (and others)
2007-08-15
In order to extend the tracking acceptance, to improve the primary and secondary vertex reconstruction and thus enhancing the tagging capabilities for short lived particles, the ZEUS experiment at the HERA Collider at DESY installed a silicon strip vertex detector. The barrel part of the detector is a 63 cm long cylinder with silicon sensors arranged around an elliptical beampipe. The forward part consists of four circular shaped disks. In total just over 200k channels are read out using 2.9 m{sup 2} of silicon. In this report a detailed overview of the design and construction of the detector is given and the performance of the completed system is reviewed. (orig.)
Eckstein, D
2003-01-01
The dedicated CP violation experiment at the LHC, LHCb, will be equipped with a novel silicon detector (VELO). The VELO will provide precise measurements of tracks from displaced $b$-vertices and will allow to trigger on them. The entire detector will be housed in a mobile secondary vacuum system, and after the injection and stabilisation of the beams each fill, the silicon detectors will move inwards and approach to within $7\\,$mm of the beams. In order to fulfil the trigger requirements, the VELO must combine in an unprecedented way the use of high resolution silicon detectors and large CPU farms. The extreme, non-uniform radiation environment puts additional constraints on the sensor design. The design of the VELO is described, along with the R\\&D of the silicon sensors and its production status.
Energy Technology Data Exchange (ETDEWEB)
Greenwood, Ross N; /MIT /SLAC
2012-09-07
Presented is the current progress of a search for the signature of a dark photon or new particle using the BaBar data set. We search for the processes e{sup +}e{sup -} {yields} {gamma}{sub ISR}A{prime},A{prime} {yields} e{sup +}e{sup -} and e{sup +}e{sup -} {yields} {gamma}{sub ISR}{gamma}, {gamma} {yields} A{prime},A{prime} {yields} e{sup +}e{sup -}, where {gamma}{sub ISR} is an initial state radiated photon of energy E{sub {gamma}} >= 1 GeV. Twenty-five sets of Monte Carlo, simulating e{sup +}e{sup -} collisions at an energy of 10.58 GeV, were produced with different values of the A{prime} mass ranging from 100 MeV to 9.5 GeV. The mass resolution is calculated based on Monte Carlo simulations. We implement ROOT's Toolkit for Multivariate Analysis (TMVA), a machine learning tool that allows us to evaluate the signal character of events based on many of discriminating variables. TMVA training is conducted with samples of Monte Carlo as signal and a small portion of Run 6 as background. The multivariate analysis produces additional cuts to separate signal and background. The signal efficiency and sensitivity are calculated. The analysis will move forward to fit the background and scan the residuals for the narrow resonance peak of a new particle.
Track Finding Efficiency in BaBar
Allmendinger, T; Brown, D N; Choi, H; Christ, S; Covarelli, R; Davier, M; Denig, A G; Fritsch, M; Hafner, A; Kowalewski, R; Long, O; Lutz, A M; Martinelli, M; Muller, D R; Nugent, I M; Pegna, D Lopes; Purohit, M V; Prencipe, E; Roney, J M; Simi, G; Solodov, E P; Telnov, A V; Varnes, E; Waldi, R; Wang, W F; White, R M
2012-01-01
We describe several studies to measure the charged track reconstruction efficiency and asymmetry of the BaBar detector. The first two studies measure the tracking efficiency of a charged particle using $\\tau$ and initial state radiation decays. The third uses the $\\tau$ decays to study the asymmetry in tracking, the fourth measures the tracking efficiency for low momentum tracks, and the last measures the reconstruction efficiency of $K_S^0$ particles. The first section also examines the stability of the measurements vs BaBar running periods.
Magnetic Wormholes and Vertex Operators
Singh, Harvendra
1994-01-01
We consider wormhole solutions in $2+1$ Euclidean dimensions. A duality transformation is introduced to derive a new action from magnetic wormhole action of Gupta, Hughes, Preskill and Wise. The classical solution is presented. The vertex operators corresponding to the wormhole are derived. Conformally coupled scalars and spinors are considered in the wormhole background and the vertex operators are computed. ( To be published in Phys. Rev. D15)
Vertex Operators for Closed Superstrings
P. A. GrassiYITP Stony Book, Piem. Orien. U., IHES; Tamassia, L.
2004-01-01
We construct an iterative procedure to compute the vertex operators of the closed superstring in the covariant formalism given a solution of IIA/IIB supergravity. The manifest supersymmetry allows us to construct vertex operators for any generic background in presence of Ramond-Ramond (RR) fields. We extend the procedure to all massive states of open and closed superstrings and we identify two new nilpotent charges which are used to impose the gauge fixing on the physical st...
Vertex covers and sensor networks
Imbesi, Maurizio; La Barbiera, Monica
2012-01-01
We consider algebraic developments of graph theory through suitable applications in real connection problems. We investigate ideals of vertex covers for the edge ideals associated to a significative class of connected graphs. It is shown that algebraic procedures linked to minimal vertex covering of such graphs are good instruments concerned about how sensor networks can be encoded and their properties measured. Moreover algebraic properties of such ideals are studied. Using the notion of lin...
c, Aleksandar Ili\\'
2011-01-01
The vertex PI index is a distance--based molecular structure descriptor, that recently found numerous chemical applications. In order to increase diversity of this topological index for bipartite graphs, we introduce weighted version defined as $PI_w (G) = \\sum_{e = uv \\in E} (deg (u) + deg (v)) (n_u (e) + n_v (e))$, where $deg (u)$ denotes the vertex degree of $u$ and $n_u (e)$ denotes the number of vertices of $G$ whose distance to the vertex $u$ is smaller than the distance to the vertex $v$. We establish basic properties of $PI_w (G)$, and prove various lower and upper bounds. In particular, the path $P_n$ has minimal, while the complete tripartite graph $K_{n/3, n/3, n/3}$ has maximal weighed vertex $PI$ index among graphs with $n$ vertices. We also compute exact expressions for the weighted vertex PI index of the Cartesian product of graphs. Finally we present modifications of two inequalities and open new perspectives for the future research.
International Nuclear Information System (INIS)
The precision measurements envisaged at the International Linear Collider (ILC) depend on excellent instrumentation and reconstruction software. The correct identification of heavy flavour jets, placing unprecedented requirements on the quality of the vertex detector, will be central for the ILC programme. This paper describes the LCFIVertex software, which provides tools for vertex finding and for identification of the flavour and charge of the leading hadron in heavy flavour jets. These tools are essential for the ongoing optimisation of the vertex detector design for linear colliders such as the ILC. The paper describes the algorithms implemented in the LCFIVertex package as well as the scope of the code and its performance for a typical vertex detector design.
Bailey, David; Grimes, Mark; Harder, Kristian; Hillert, Sonja; Jackson, David; Jayawardena, Talini Pinto; Jeffery, Ben; Lastovicka, Tomas; Lynch, Clare; Martin, Victoria; Walsh, Roberval; Allport, Phil; Banda, Yambazi; Buttar, Craig; Cheplakov, Alexandre; Cussans, David; Damerell, Chris; de Groot, Nicolo; Fopma, Johan; Foster, Brian; Galagedera, Senerath; Gao, Rui; Gillman, Anthony; Goldstein, Joel; Greenshaw, Timothy; Halsall, Robert; Hawes, Brian; Hayrapetyan, Karen; Heath, Helen; John, Jaya; Johnson, Erik; Kundu, Nikhil; Laing, Andrew; Lastovicka-Medin, Gordana; Lau, Wing; Li, Yiming; Lintern, Andrew; Mandry, Scott; Murray, Peter; Nichols, Andy; Nomerotski, Andrei; Page, Ryan; Parkes, Chris; Perry, Colin; O'Shea, Val; Sopczak, Andre; Stefanov, Konstantin; Tabassam, Hajrah; Thomas, Stephen; Tikkanen, Tuomo; Turchetta, Renato; Tyndel, Mike; Velthuis, Jaap; Villani, Giulio; Wijnen, Thei; Woolliscroft, Tim; Worm, Steven; Yang, Stephanie; Zhang, Zhige
2009-01-01
The precision measurements envisaged at the International Linear Collider (ILC) depend on excellent instrumentation and reconstruction software. The correct identification of heavy flavour jets, placing unprecedented requirements on the quality of the vertex detector, will be central for the ILC programme. This paper describes the LCFIVertex software, which provides tools for vertex finding and for identification of the flavour and charge of the leading hadron in heavy flavour jets. These tools are essential for the ongoing optimisation of the vertex detector design for linear colliders such as the ILC. The paper describes the algorithms implemented in the LCFIVertex package, as well as the scope of the code and its performance for a typical vertex detector design.
Vertex detectors: The state of the art and future prospects
International Nuclear Information System (INIS)
We review the current status of vertex detectors (tracking microscopes for the recognition of charm and bottom particle decays). The reasons why silicon has become the dominant detector medium are explained. Energy loss mechanisms are reviewed, as well as the physics and technology of semiconductor devices, emphasizing the areas of most relevance for detectors. The main design options (microstrips and pixel devices, both CCD's and APS's) are discussed, as well as the issue of radiation damage, which probably implies the need to change to detector media beyond silicon for some vertexing applications. Finally, the evolution of key performance parameters over the past 15 years is reviewed, and an attempt is made to extrapolate to the likely performance of detectors working at the energy frontier ten years from now
Vertex detectors: The state of the art and future prospects
Energy Technology Data Exchange (ETDEWEB)
Damerell, C.J.S. [Rutherford Appleton Laboratory, Didcot (United Kingdom)
1997-01-01
We review the current status of vertex detectors (tracking microscopes for the recognition of charm and bottom particle decays). The reasons why silicon has become the dominant detector medium are explained. Energy loss mechanisms are reviewed, as well as the physics and technology of semiconductor devices, emphasizing the areas of most relevance for detectors. The main design options (microstrips and pixel devices, both CCD`s and APS`s) are discussed, as well as the issue of radiation damage, which probably implies the need to change to detector media beyond silicon for some vertexing applications. Finally, the evolution of key performance parameters over the past 15 years is reviewed, and an attempt is made to extrapolate to the likely performance of detectors working at the energy frontier ten years from now.
The BABAR detector: Upgrades, operation and performance
Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; del Amo Sanchez, P.; Gaillard, J.-M.; Hicheur, A.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prudent, X.; Robbe, P.; Tisserand, V.; Zghiche, A.; Grauges, E.; Garra Tico, J.; Lopez, L.; Martinelli, M.; Palano, A.; Pappagallo, M.; Pompili, A.; Chen, G. P.; Chen, J. C.; Qi, N. D.; Rong, G.; Wang, P.; Zhu, Y. S.; Eigen, G.; Stugu, B.; Sun, L.; Abrams, G. S.; Battaglia, M.; Borgland, A. W.; Breon, A. B.; Brown, D. N.; Button-Shafer, J.; Cahn, R. N.; Charles, E.; Clark, A. R.; Day, C. T.; Furman, M.; Gill, M. S.; Groysman, Y.; Jacobsen, R. G.; Kadel, R. W.; Kadyk, J. A.; Kerth, L. T.; Kolomensky, Yu. G.; Kral, J. F.; Kukartsev, G.; LeClerc, C.; Levi, M. E.; Lynch, G.; Merchant, A. M.; Mir, L. M.; Oddone, P. J.; Orimoto, T. J.; Osipenkov, I. L.; Pripstein, M.; Roe, N. A.; Romosan, A.; Ronan, M. T.; Shelkov, V. G.; Suzuki, A.; Tackmann, K.; Tanabe, T.; Wenzel, W. A.; Zisman, M.; Barrett, M.; Bright-Thomas, P. G.; Ford, K. E.; Harrison, T. J.; Hart, A. J.; Hawkes, C. M.; Knowles, D. J.; Morgan, S. E.; O'Neale, S. W.; Penny, R. C.; Smith, D.; Soni, N.; Watson, A. T.; Watson, N. K.; Goetzen, K.; Held, T.; Koch, H.; Kunze, M.; Lewandowski, B.; Pelizaeus, M.; Peters, K.; Schmuecker, H.; Schroeder, T.; Steinke, M.; Fella, A.; Antonioli, E.; Boyd, J. T.; Chevalier, N.; Cottingham, W. N.; Foster, B.; Mackay, C.; Walker, D.; Abe, K.; Asgeirsson, D. J.; Cuhadar-Donszelmann, T.; Fulsom, B. G.; Hearty, C.; Knecht, N. S.; Mattison, T. S.; McKenna, J. A.; Thiessen, D.; Khan, A.; Kyberd, P.; McKemey, A. K.; Randle-Conde, A.; Saleem, M.; Sherwood, D. J.; Teodorescu, L.; Blinov, V. E.; Bukin, A. D.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Korol, A. A.; Kravchenko, E. A.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Telnov, V. I.; Todyshev, K. Yu.; Yushkov, A. N.; Best, D. S.; Bondioli, M.; Bruinsma, M.; Chao, M.; Curry, S.; Eschrich, I.; Kirkby, D.; Lankford, A. J.; Mandelkern, M.; Martin, E. C.; McMahon, S.; Mommsen, R. K.; Stoker, D. P.; Abachi, S.; Buchanan, C.; Hartfiel, B. L.; Weinstein, A. J. R.; Atmacan, H.; Foulkes, S. D.; Gary, J. W.; Layter, J.; Liu, F.; Long, O.; Shen, B. C.; Vitug, G. M.; Wang, K.; Yasin, Z.; Zhang, L.; Hadavand, H. K.; Hill, E. J.; Paar, H. P.; Rahatlou, S.; Schwanke, U.; Sharma, V.; Berryhill, J. W.; Campagnari, C.; Cunha, A.; Dahmes, B.; Hong, T. M.; Kovalskyi, D.; Kuznetsova, N.; Levy, S. L.; Lu, A.; Mazur, M. A.; Richman, J. D.; Verkerke, W.; Beck, T. W.; Beringer, J.; Eisner, A. M.; Flacco, C. J.; Grillo, A. A.; Grothe, M.; Heusch, C. A.; Kroseberg, J.; Lockman, W. S.; Martinez, A. J.; Nesom, G.; Schalk, T.; Schmitz, R. E.; Schumm, B. A.; Seiden, A.; Spencer, E.; Spradlin, P.; Turri, M.; Walkowiak, W.; Wang, L.; Wilder, M.; Williams, D. C.; Wilson, M. G.; Winstrom, L. O.; Chen, E.; Cheng, C. H.; Doll, D. A.; Dorsten, M. P.; Dvoretskii, A.; Echenard, B.; Erwin, R. J.; Fang, F.; Flood, K.; Hitlin, D. G.; Metzler, S.; Narsky, I.; Oyang, J.; Piatenko, T.; Porter, F. C.; Ryd, A.; Samuel, A.; Yang, S.; Zhu, R. Y.; Andreassen, R.; Devmal, S.; Geld, T. L.; Jayatilleke, S.; Mancinelli, G.; Meadows, B. T.; Mishra, K.; Sokoloff, M. D.; Abe, T.; Antillon, E. A.; Barillari, T.; Becker, J.; Blanc, F.; Bloom, P. C.; Chen, S.; Clifton, Z. C.; Derrington, I. M.; Destree, J.; Dima, M. O.; Ford, W. T.; Gaz, A.; Gilman, J. D.; Hachtel, J.; Hirschauer, J. F.; Johnson, D. R.; Kreisel, A.; Nagel, M.; Nauenberg, U.; Olivas, A.; Rankin, P.; Roy, J.; Ruddick, W. O.; Smith, J. G.; Ulmer, K. A.; van Hoek, W. C.; Wagner, S. R.; West, C. G.; Zhang, J.; Ayad, R.; Blouw, J.; Chen, A.; Eckhart, E. A.; Harton, J. L.; Hu, T.; Toki, W. H.; Wilson, R. J.; Winklmeier, F.; Zeng, Q. L.; Altenburg, D.; Feltresi, E.; Hauke, A.; Jasper, H.; Karbach, M.; Merkel, J.; Petzold, A.; Spaan, B.; Wacker, K.; Brandt, T.; Brose, J.; Colberg, T.; Dahlinger, G.; Dickopp, M.; Eckstein, P.; Futterschneider, H.; Kaiser, S.; Kobel, M. J.; Krause, R.; Müller-Pfefferkorn, R.; Mader, W. F.; Maly, E.; Nogowski, R.; Otto, S.; Schubert, J.; Schubert, K. R.; Schwierz, R.; Sundermann, J. E.; Volk, A.; Wilden, L.; Bernard, D.; Brochard, F.; Cohen-Tanugi, J.; Dohou, F.; Ferrag, S.; Latour, E.; Mathieu, A.; Renard, C.; Schrenk, S.; T'Jampens, S.; Thiebaux, Ch.; Vasileiadis, G.; Verderi, M.; Anjomshoaa, A.; Bernet, R.; Clark, P. J.; Lavin, D. R.; Muheim, F.; Playfer, S.; Robertson, A. I.; Swain, J. E.; Watson, J. E.; Xie, Y.; Andreotti, D.; Andreotti, M.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Carassiti, V.; Cecchi, A.; Cibinetto, G.; Cotta Ramusino, A.; Evangelisti, F.; Fioravanti, E.; Franchini, P.; Garzia, I.; Landi, L.; Luppi, E.; Malaguti, R.; Negrini, M.; Padoan, C.; Petrella, A.; Piemontese, L.; Santoro, V.; Sarti, A.; Anulli, F.; Baldini-Ferroli, R.
2013-11-01
The BABAR detector operated successfully at the PEP-II asymmetric e+e- collider at the SLAC National Accelerator Laboratory from 1999 to 2008. This report covers upgrades, operation, and performance of the collider and the detector systems, as well as the trigger, online and offline computing, and aspects of event reconstruction since the beginning of data taking.
The LHCb Vertex Locator – Performance and Radiation Damage
Oblakowska-Mucha, A
2014-01-01
LHCb is a dedicated flavour physics experiment at the Large Hadron Collider at CERN. The Vertex Locator (VELO) is an important part of a LHCb tracking system, enabling precision measurement of beauty and charm mesons’ flight distance. The VELO consist of a set of silicon micro-strip detectors, arranged in two retractable halves, operating only 7 mm from the interac- tion region. In these proceedings the VELO performance during the Run 1 is summarised and radiation damage studies are presented.
Energy Technology Data Exchange (ETDEWEB)
Lafferty, G.D.; /Manchester U.
2005-08-29
Some recent results in hadron physics from the BaBar experiment are discussed. In particular, the observation of two new charmed states, the D*{sub sJ}{sup +}(2317) and the D*{sub sJ}{sup +}(2457), is described, and results are presented on the first measurement of the rare decay mode of the B meson, B{sup 0} {pi}{sup 0}{pi}{sup 0}.
International Nuclear Information System (INIS)
The BABAR experiment at SLAC has just presented its first physics results, with the primary attention on the expected measurement of the CP-violating sin(2β) parameter. Apart from the observation of CP asymmetries, the first year of operation has led to a variety of results that are already competitive with the world's best measurements. We present a selection of these results including BB-bar mixing, B lifetimes and a variety of branching fractions, in particular for rare B decays
Semileptonic and Electroweak Penguin Results from BABAR
Walsh, J; Barate, R; Boutigny, D; Couderc, F; Karyotakis, Yu; Lees, J P; Poireau, V; Tisserand, V; Zghiche, A; Graugès-Pous, E; Palano, A; Pappagallo, M; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Battaglia, M; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Wenzel, W A; Barrett, M; Ford, K E; Harrison, T J; Hart, A J; Hawkes, C M; Morgan, S E; Watson, A T; Fritsch, M; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schröder, T; Steinke, M; Boyd, J T; Burke, J P; Chevalier, N; Cottingham, W N; Kelly, M P; Çuhadar-Dönszelmann, T; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Khan, A; Kyberd, P; Teodorescu, L; Blinov, A E; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bondioli, M; Bruinsma, M; Chao, M; Eschrich, I; Kirkby, D; Lankford, A J; Mandelkern, M A; Mommsen, R K; Röthel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Weinstein, A J R; Foulkes, S D; Gary, J W; Long, O; Shen, B C; Wang, K; Zhang, L; Del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Eisner, A M; Flacco, C J; Heusch, C A; Kroseberg, J; Lockman, W S; Nesom, G; Schalk, T; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Andreassen, R; Jayatilleke, S M; Mancinelli, G; Meadows, B T; Sokoloff, M D; Blanc, F; Bloom, P; Chen, S; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Ruddick, W O; Smith, J G; Ulmer, K A; Wagner, S R; Zhang, J; Chen, A; Eckhart, E A; Soffer, A; Toki, W H; Wilson, R J; Zeng, Q; Feltresi, E; Hauke, A; Spaan, B; Altenburg, D; Brandt, T; Brose, J; Dickopp, M; Klose, V; Lacker, H M; Nogowski, R; Otto, S; Petzold, A; Schott, G; Schubert, J; Schubert, K R; Schwierz, R; Sundermann, J E; Bernard, D; Bonneaud, G R; Grenier, P; Schrenk, S; Thiebaux, C; Vasileiadis, G; Verderi, M; Bard, D J; Clark, P J; Gradl, W; Muheim, F; Playfer, S; Xie, Y; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; De Sangro, R; Finocchiaro, G; Patteri, P; Peruzzi, I M; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Brandenburg, G; Chaisanguanthum, K S; Morii, M; Won, E; Dubitzky, R S; Langenegger, U; Marks, J; Schenk, S; Uwer, U; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Flack, R L; Gaillard, J R; Morton, G W; Nash, J A; Nikolich, M B; Taylor, G P; Charles, M J; Mader, W F; Mallik, U; Mohapatra, A K; Cochran, J; Crawley, H B; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Yi, J; Arnaud, N; Davier, M; Giroux, X; Grosdidier, G; Höcker, A; Le Diberder, F R; Lepeltier, V; Lutz, A M; Oyanguren, A; Petersen, T C; Pierini, M; Plaszczynski, S; Rodier, S; Roudeau, P; Schune, M H; Stocchi, A; Wormser, G; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Chavez, C A; Coleman, J P; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; George, K A; Hutchcroft, D E; Parry, R J; Payne, D J; Schofield, K C; Touramanis, C; Cormack, C M; Di Lodovico, F; Sacco, R; Brown, C L; Cowan, G; Flächer, H U; Green, M G; Hopkins, D A; Jackson, P S; McMahon, T R; Ricciardi, S; Salvatore, F; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hodgkinson, M C; Lafferty, G D; Naisbit, M T; Williams, J C; Chen, C; Farbin, A; Hulsbergen, W D; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Simi, G; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Kofler, R; Koptchev, V B; Li, X; Moore, T B; Saremi, S; Stängle, H; Willocq, S; Cowan, R; Koeneke, K; Sciolla, G; Sekula, S J; Taylor, F; Yamamoto, R K; Kim, H; Patel, P M; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Taras, P; Viaud, B; Nicholson, H; Cavallo, N; De Nardo, Gallieno; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M; Bulten, H; Raven, G; Snoek, H L; Wilden, L; Jessop, C P; LoSecco, J M; Allmendinger, T; Benelli, G; Gan, K K; Honscheid, K; Hufnagel, D; Jackson, P D; Kagan, H; Kass, R; Pulliam, T; Rahimi, A M; Ter-Antonian, R; Wong, Q K; Brau, J E; Frey, R; Igonkina, O; Lu, M; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; Del Buono, L; La Vaissière, C de; Hamon, O; John, M J J; Leruste, P; Malcles, J; Ocariz, J; Roos, L; Therin, G; Behera, P K; Gladney, L; Guo, Q H; Panetta, J; Biasini, M; Covarelli, R; Pacetti, S; Pioppi, M; Angelini, C; Batignani, G; Bettarini, S; Bucci, F; Calderini, G; Carpinelli, M; Cenci, R; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Walsh, J; Haire, M; Judd, D; Paick, K; Wagoner, D E; Biesiada, J; Danielson, N; Elmer, P; Lau, Y P; Lü, C; Olsen, J; Smith, A J S; Telnov, A V; Bellini, F; Cavoto, G; D'Orazio, A; Di, E; Marco; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Li Gioi, L; Mazzoni, M A; Morganti, S; Piredda, G; Polci, F; Safai-Tehrani, F; Voena, C; Schröder, H; Wagner, G; Waldi, R; Adye, T; De, N; De Groot, J G H; Franek, B; Gopal, G P; Olaiya, E O; Wilson, F F; Aleksan, Roy; Emery, S; Gaidot, A; Ganzhur, S F; Giraud, P F; Graziani, G; Hamel de Monchenault, G; Kozanecki, Witold; Legendre, M; London, G W; Mayer, B; Vasseur, G; Yéche, C; Zito, M; Purohit, M V; Weidemann, A W; Wilson, J R; Yumiceva, F X; Abe, T; Allen, M T; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmüller, O L; Claus, R; Convery, M R; Cristinziani, M; Dingfelder, J C; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W M; Fan, S; Field, R C; Glanzman, T; Gowdy, S J; Hadig, T; Halyo, V; Hast, C; Hrynóva, T; Innes, W R; Kelsey, M H; Kim, P; Kocian, M L; Leith, D W G S; Libby, J; Luitz, S; Lüth, V; Lynch, H L; Marsiske, H; Messner, R; Müller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Stelzer, J; Strube, J; Su, D; Sullivan, M K; Suzuki, K; Swain, S; Thompson, J M; Vavra, J; Weaver, M; Wisniewski, W J; Wittgen, M; Wright, D H; Yarritu, A K; Yi, K; Young, C C; Burchat, Patricia R; Edwards, A J; Majewski, S A; Petersen, B A; Roat, C; Ahmed, M; Ahmed, S; Alam, M S; Ernst, J A; Saeed, M A; Saleem, M; Wappler, F R; Zain, S B; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Ritchie, J L; Satpathy, A; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bóna, M; Gallo, F; Gamba, D; Bomben, M; Bosisio, L; Cartaro, C; Cossutti, F; Della, G; Ricca; Dittongo, S; Grancagnolo, S; Lanceri, L; Poropat, P; Vitale, L; Martínez-Vidal, F; Panvini, R S; Banerjee, S; Bhuyan, B; Brown, C M; Fortin, D; Hamano, K; Kowalewski, R V; Roney, J M; Sobie, R J; Back, J J; Harrison, P F; Latham, T E; Mohanty, G B; Band, H R; Chen, X; Cheng, B; Dasu, S; Datta, M; Eichenbaum, A M; Flood, K T; Graham, M; Hollar, J J; Johnson, J R; Kutter, P E; Li, H; Liu, R; Mellado, B; Mihályi, A; Pan, Y; Prepost, R; Tan, P; Von Wimmersperg-Töller, J H; Wu, J; Wu, S L; Yu, Z; Greene, M G; Neal, H; Walsh, John
2005-01-01
We report recent results from the BABAR experiment on semileptonic charmless B-meson decays and electroweak penguin processes. Semileptonic charmless decays are used to determine |Vub| and the exclusive modes considered here also begin to constrain QCD-lattice form factor calculations. Radiative penguin decays are both sensitive to physics beyond the Standard Model and can be used to extract Heavy Quark parameters related to the b-quark mass and its motion inside the hadron.
Vertex operators and Jordan fields
International Nuclear Information System (INIS)
The construction of Lie algebras in terms of Jordan algebras generators is discussed. The key to the construction is the triality relation already incorporated into matrix products. A generalisation to Kac-Moody algebras in terms of vertex operators is proposed and may provide a clue for the construction of new representations of Kac-Moody algebras in terms of Jordan fields. (author)
Vertex detection at the Tevatron
International Nuclear Information System (INIS)
Addition of vertex detectors to CDF and DO will facilitate a rich program of beauty physics at the Tevatron, and may enable tags of B and τ which facilitate searches for top and other heavy objects. The authors also address the operational considerations of triggering and radiation protection, and speculate on possible directions for upgrades
Orbanic, Alen; Petkovsek, Marko; Pisanski, Tomaz; Potocnik, Primoz
2008-01-01
The number of distinct maps (pre-maps) with a single vertex and valence $d$ is computed for any value of $d$. The types of maps (pre-maps) that we consider depend on whether the underlaying graph (pre-graph) is signed or unsigned and directed or undirected.
Particle-Particle-String Vertex
Ishibashi, Nobuyuki
1996-01-01
We study a theory of particles interacting with strings. Considering such a theory for Type IIA superstring will give some clue about M-theory. As a first step toward such a theory, we construct the particle-particle-string interaction vertex generalizing the D-particle boundary state.
The BaBar Data Acquisition System
Scott, I; Grosso, P; Huffer, M E; O'Grady, C; Russell, J J
1999-01-01
The BaBar experiment at the Stanford Linear Accelerator Center is designed to perform a search for CP violation by ana-lyzing the decays of a very large sample of B and B(Bar) mesons produced at the high luminosity PEP-II accelerator. The data acquisition system must cope with a sustained high event rate, while supporting real time feature extraction and data compression with minimal dead time. The BaBar data acquisition system is based around a common VME interface to the electronics read-out of the separate detec-tor subsystems. Data from the front end electronics is read into commercial VME processors via a custom "Personality Card" and PCI interface. The commercial CPUs run the Tornado operating system to provide a platform for detector subsystem code to perform the necessary data processing. The data is read out via a non-blocking network switch to a farm of commercial UNIX processors. The current implementation of the BaBar data acquisition sys-tem has been shown to sustain a Level 1 trigger rate of 1.3...
Radiation damage in the LHCb Vertex Locator
Affolder, A; Alexander, M; Ali, S; Artuso, M; Benton, J; van Beuzekom, M; Bjørnstad, P M; Bogdanova, G; Borghi, S; Bowcock, T J V; Brown, H; Buytaert, J; Casse, G; Collins, P; De Capua, S; Dossett, D; Eklund, L; Farinelli, C; Garofoli, J; Gersabeck, M; Gershon, T; Gordon, H; Harrison, J; Heijne, V; Hennessy, K; Hutchcroft, D; Jans, E; John, M; Ketel, T; Lafferty, G; Latham, T; Leflat, A; Liles, M; Moran, D; Mous, I; Oblakowska-Mucha, A; Parkes, C; Patel, G D; Redford, S; Reid, M M; Rinnert, K; Rodrigues, E; Schiller, M; Szumlak, T; Thomas, C; Velthuis, J; Volkov, V; Webber, A D; Whitehead, M; Zverev, E
2013-01-01
The LHCb Vertex Locator (VELO) is a silicon strip detector designed to reconstruct charged particle trajectories and vertices produced at the LHCb interaction region. During the first two years of data collection, the 84 VELO sensors have been exposed to a range of fluences up to a maximum value of approximately $\\rm{45 \\times 10^{12}\\,1\\,MeV}$ neutron equivalent ($\\rm{1\\,MeV\\,n_{eq}}$). At the operational sensor temperature of approximately $-7\\,^{\\circ}\\rm{C}$, the average rate of sensor current increase is 18$\\mu$ A per $\\rm{fb^{-1}}$, in excellent agreement with predictions. The silicon effective bandgap has been determined using current versus temperature scan data after irradiation, with an average value of $E_{g}=1.16\\pm0.03\\pm0.04\\,\\rm{eV}$ obtained. The first observation of n-on-n sensor type inversion at the LHC has been made, occurring at a fluence of around $15 \\times 10 ^{12}$ of $1\\,\\rm{MeV\\,n_{eq}}$. The only n-on-p sensors in use at the LHC have also been studied. With an initial fluence of ap...
Vertex operator (super)algebras and LCFT
International Nuclear Information System (INIS)
We review some of the developments in logarithmic conformal field theory from the vertex algebra point of view. Several important examples of vertex operator (super)algebras of the triplet type are discussed, including their representation theory. Particular emphasis is put on C2-cofiniteness of these vertex algebras, a description of Zhu’s algebras and the construction of logarithmic modules. (review)
Status and prospects of the LHCb Vertex Locator
van Beuzekom, Martin
2007-01-01
The Vertex Locator of the LHCb experiment is a dedicated subdetector for the reconstruction of primary and secondary vertices in b-hadron decays. The vertex detector features two halves with 21 modules each, mounted on retractable bases. Each module consists of two half-disk silicon micro-strip sensors measuring hits in R and $\\Phi$ coordinates. The strip pitch ranges from 40 to about 100 $\\mu$m. A vacuum boy with a 300 $\\mu$m thick aluminium foil shields the sensors from the wakefields of the proton beams which are passing at a distance of 8 mm from the active area of the sensors. Because of the harsh non-uniform radiation environment we opted for n-on-n strips in diffusion oxygenated float zone silicon. The current status of the vertex detector, which has recently entered the commissioning phase, will be discussed. Given the limited lifetime of the detector due to the radiation environment, developments for a detector replacement with n-on-p type modules have already started. Possible upgrade scenarios fo...
Performance of the LHCb Vertex Locator
International Nuclear Information System (INIS)
The Vertex Locator (VELO) is a silicon microstrip detector that surrounds the proton-proton interaction region in the LHCb experiment. The performance of the detector during the first years of its physics operation is reviewed. The system is operated in vacuum, uses a bi-phase CO2 cooling system, and the sensors are moved to 7 mm from the LHC beam for physics data taking. The performance and stability of these characteristic features of the detector are described, and details of the material budget are given. The calibration of the timing and the data processing algorithms that are implemented in FPGAs are described. The system performance is fully characterised. The sensors have a signal to noise ratio of approximately 20 and a best hit resolution of 4 μm is achieved at the optimal track angle. The typical detector occupancy for minimum bias events in standard operating conditions in 2011 is around 0.5%, and the detector has less than 1% of faulty strips. The proximity of the detector to the beam means that the inner regions of the n+-on-n sensors have undergone space-charge sign inversion due to radiation damage. The VELO performance parameters that drive the experiment's physics sensitivity are also given. The track finding efficiency of the VELO is typically above 98% and the modules have been aligned to a precision of 1 μm for translations in the plane transverse to the beam. A primary vertex resolution of 13 μm in the transverse plane and 71 μm along the beam axis is achieved for vertices with 25 tracks. An impact parameter resolution of less than 35 μm is achieved for particles with transverse momentum greater than 1 GeV/c
A Novel Vertex Affinity for Community Detection
Energy Technology Data Exchange (ETDEWEB)
Yoo, Andy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sanders, Geoffrey [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Henson, Van [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Vassilevski, Panayot [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2015-10-05
We propose a novel vertex affinity measure in this paper. The new vertex affinity quantifies the proximity between two vertices in terms of their clustering strength and is ideal for such graph analytics applications as community detection. We also developed a framework that combines simple graph searches and resistance circuit formulas to compute the vertex affinity efficiently. We study the properties of the new affinity measure empirically in comparison to those of other popular vertex proximity metrics. Our results show that the existing metrics are ill-suited for community detection due to their lack of fundamental properties that are essential for correctly capturing inter- and intra-cluster vertex proximity.
OPAL Central Detector (Including vertex, jet and Z chambers)
OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. OPAL's central tracking system consists of (in order of increasing radius) a silicon microvertex detector, a vertex detector, a jet chamber, and z-chambers. All the tracking detectors work by observing the ionization of atoms by charged particles passing by: when the atoms are ionized, electrons are knocked out of their atomic orbitals, and are then able to move freely in the detector. These ionization electrons are detected in the different parts of the tracking system. (This piece includes the vertex, jet and Z chambers) In the picture above, the central detector is the piece being removed to the right.
Charm and Charmonium Spectroscopy in BaBar
Energy Technology Data Exchange (ETDEWEB)
Negrini, M.; /Ferrara U.
2008-02-06
The BABAR experiment at the PEP-II B-factory offers excellent opportunities in charm and charmonium spectroscopy. The recent observation of new states in the D{sub s} and in the charmonium mass regions revived the interest in this field. Recent BABAR results are presented.
Energy Technology Data Exchange (ETDEWEB)
McGregor, Grant Duncan
2008-12-16
In this thesis we examine the method of counting B{bar B} events produced in the BABAR experiment. The original method was proposed in 2000, but improvements to track reconstruction and our understanding of the detector since that date make it appropriate to revisit the B Counting method. We propose a new set of cuts designed to minimize the sensitivity to time-varying backgrounds. We find the new method counts B{bar B} events with an associated systematic uncertainty of {+-} 0.6%.
Managing the BABAR Object Oriented Database
International Nuclear Information System (INIS)
The BaBar experiment stores its data in an Object Oriented federated database supplied by Objectivity/DB(tm). This database is currently 350TB in size and is expected to increase considerably as the experiment matures. Management of this database requires careful planning and specialized tools in order to make the data available to physicists in an efficient and timely manner. We discuss the operational issues and management tools that were developed during the previous run to deal with this vast quantity of data at SLAC
String bits and the spin vertex
Directory of Open Access Journals (Sweden)
Yunfeng Jiang
2015-08-01
Full Text Available We initiate a novel formalism for computing correlation functions of trace operators in the planar N=4 SYM theory. The central object in our formalism is the spin vertex which is the weak coupling analogy of the string vertex in string field theory. We construct the spin vertex explicitly for all sectors at the leading order using a set of bosonic and fermionic oscillators. We prove that the vertex has trivial monodromy, or put in other words, it is a Yangian invariant. Since the monodromy of the vertex is the product of the monodromies of the three states, the Yangian invariance of the vertex implies an infinite exact symmetry for the three-point function. We conjecture that this infinite symmetry can be lifted to any loop order.
The vacuum system of the LHCb vertex detector
Van den Brand, J F J; Kraan, M G; Klous, S; Kaan, A P
2002-01-01
An overview of the design of the vertex detector of the LHCb experiment in the future Large Hadron Collider at CERN will be given. The application of silicon detectors close to the beam implies the isolation of the materials with a high desorption rate from the accelerator vacuum. The aluminium containment has a complicated shape and a thickness of 250 mu m in order to minimize the multiple scattering. Alignment, safety and precision problems have been solved in the design and are being tested. (1 refs).
Performance of the LHCb Vertex Locator
Aaij, R; Akiba, K; Alexander, M; Ali, S; Appleby, R B; Artuso, M; Bates, A; Bay, A; Behrendt, O; Benton, J; van Beuzekom, M; Bjornstad, P M; Bogdanova, G; Borghi, S; Borgia, A; Bowcock, T J V; van den Brand, J; Brown, H; Buytaert, J; Callot, O; Carroll, J; Casse, G; Collins, P; De Capua, S; Doets, M; Donleavy, S; Dossett, D; Dumps, R; Eckstein, D; Eklund, L; Farinelli, C; Farry, S; Ferro-Luzzi, M; Frei, R; Garofoli, J; Gersabeck, M; Gershon, T; Gong, A; Gong, H; Gordon, H; Haefeli, G; Harrison, J; Heijne, V; Hennessy, K; Hulsbergen, W; Huse, T; Hutchcroft, D; Jaeger, A; Jalocha, P; Jans, E; John, M; Keaveney, J; Ketel, T; Korolev, M; Kraan, M; Lastovicka, T; Laﬀerty, G; Latham, T; Lefeuvre, G; Leﬂat, A; Liles, M; van Lysebetten, A; MacGregor, G; Marinho, F; McNulty, R; Merkin, M; Moran, D; Mountain, R; Mous, I; Mylroie-Smith, J; Needham, M; Nikitin, N; Noor, A; Oblakowska-Mucha, A; Papadelis, A; Pappagallo, M; Parkes, C; Patel, G D; Rakotomiaramanana, B; Redford, S; Reid, M; Rinnert, K; Rodrigues, E; Saavedra, A F; Schiller, M; Schneider, O; Shears, T; Silva Coutinho, R; Smith, N A; Szumlak, T; Thomas, C; van Tilburg, J; Tobin, M; Velthuis, J; Verlaat, B; Viret, S; Volkov, V; Wallace, C; Wang, J; Webber, A; Whitehead, M; Zverev, E
2014-01-01
The Vertex Locator (VELO) is a silicon microstrip detector that surrounds the proton-proton interaction region in the LHCb experiment. The performance of the detector during the first years of its physics operation is reviewed. The system is operated in vacuum, uses a bi-phase CO2 cooling system, and the sensors are moved to 7 mm from the LHC beam for physics data taking. The performance and stability of these characteristic features of the detector are described, and details of the material budget are given. The calibration of the timing and the data processing algorithms that are implemented in FPGAs are described. The system performance is fully characterised. The sensors have a signal to noise ratio of approximately 20 and a best hit resolution of 4 microns is achieved at the optimal track angle. The typical detector occupancy for minimum bias events in standard operating conditions in 2011 is around 0.5%, and the detector has less than 1% of faulty strips. The proximity of the detector to the beam means ...
Radiation damage in the LHCb vertex locator
Affolder, A.; Akiba, K.; Alexander, M.; Ali, S.; Artuso, M.; Benton, J.; van Beuzekom, M.; BjØrnstad, P. M.; Bogdanova, G.; Borghi, S.; Bowcock, T. J. V.; Brown, H.; Buytaert, J.; Casse, G.; Collins, P.; De Capua, S.; Dossett, D.; Eklund, L.; Farinelli, C.; Garofoli, J.; Gersabeck, M.; Gershon, T.; Gordon, H.; Harrison, J.; Heijne, V.; Hennessy, K.; Hutchcroft, D.; Jans, E.; John, M.; Ketel, T.; Lafferty, G.; Latham, T.; Leflat, A.; Liles, M.; Moran, D.; Mous, I.; Oblakowska-Mucha, A.; Parkes, C.; Patel, G. D.; Redford, S.; Reid, M. M.; Rinnert, K.; Rodrigues, E.; Schiller, M.; Szumlak, T.; Thomas, C.; Velthuis, J.; Volkov, V.; Webber, A. D.; Whitehead, M.; Zverev, E.
2013-08-01
The LHCb Vertex Locator (VELO) is a silicon strip detector designed to reconstruct charged particle trajectories and vertices produced at the LHCb interaction region. During the first two years of data collection, the 84 VELO sensors have been exposed to a range of fluences up to a maximum value of approximately 45 × 1012 1 MeV neutron equivalent (1 MeV neq). At the operational sensor temperature of approximately -7 °C, the average rate of sensor current increase is 18 μA per fb-1, in excellent agreement with predictions. The silicon effective bandgap has been determined using current versus temperature scan data after irradiation, with an average value of Eg = 1.16±0.03±0.04 eV obtained. The first observation of n+-on-n sensor type inversion at the LHC has been made, occurring at a fluence of around 15 × 1012 of 1 MeV neq. The only n+-on-p sensors in use at the LHC have also been studied. With an initial fluence of approximately 3 × 1012 1 MeV neq, a decrease in the Effective Depletion Voltage (EDV) of around 25 V is observed. Following this initial decrease, the EDV increases at a comparable rate to the type inverted n+-on-n type sensors, with rates of (1.43±0.16) × 10-12 V/ 1 MeV neq and (1.35±0.25) × 10-12 V/ 1 MeV neq measured for n+-on-p and n+-on-n type sensors, respectively. A reduction in the charge collection efficiency due to an unexpected effect involving the second metal layer readout lines is observed.
Alipour Tehrani, Niloufar
2016-07-01
A vertex detector concept is under development for the proposed multi-TeV linear e+e- Compact Linear Collider (CLIC). To perform precision physics measurements in a challenging environment, the CLIC vertex detector pushes the technological requirements to the limits. This paper reviews the requirements for the CLIC vertex detector and gives an overview of recent R&D achievements in the domains of sensor, readout, powering and cooling.
Data driven processor 'Vertex Trigger' for B experiments
International Nuclear Information System (INIS)
Data Driven Processors (DDP's) are specialized computation engines configured to solve specific numerical problems, such as vertex reconstruction. The architecture of the DDP which is the subject of this talk was designed and implemented by W. Sippach and B.C. Knapp at Nevis Lab. in the early 1980's. This particular implementation allows multiple parallel streams of data to provide input to a heterogenous collection of simple operators whose interconnection form an algorithm. The local data flow control allows this device to execute algorithms extremely quickly provided that care is taken in the layout of the algorithm. I/O rates of several hundred megabytes/second are routinely achieved thus making DDP's attractive candidates for complex online calculations. The original question was open-quote can a DDP reconstruct tracks in a Silicon Vertex Detector, find events with a separated vertex and do it fast enough to be used as an online trigger?close-quote Restating this inquiry as three questions and describing the answers to the questions will be the subject of this talk. The three specific questions are: (1) Can an algorithm be found which reconstructs tracks in a planar geometry and no magnetic field; (2) Can separated vertices be recognized in some way; (3) Can the algorithm be implemented in the Nevis-UMass and DDP and execute in 10-20 μs?
A new construction for vertex decomposable graphs
Directory of Open Access Journals (Sweden)
Nasser Hajisharifi
2016-09-01
Full Text Available Let G be a finite simple graph on the vertex set V(G and let S⊆V(G. Adding a whisker to G at x means adding a new vertex y and edge xy to G where x∈V(G. The graph G∪W(S is obtained from G by adding a whisker to every vertex of S. We prove that if G∖S is either a graph with no chordless cycle of length other than 3 or 5, chordal graph or C5, then G∪W(S is a vertex decomposable graph.
Light Higgs And Dark Photon Searches at BABAR
Energy Technology Data Exchange (ETDEWEB)
Perez Perez, Alejandro [INFN, Pisa (Italy)
2015-02-06
Several new-physics (NP) models predict the existence of low-mass Higgs states and light dark matter candidates. Previous BABAR searches have given null results for these new states and have excluded large regions of the NP models parameter space. We report on new searches on light Higgs and light dark matter at BABAR using the 516 fb^{-1} of data collected with the BABAR detector at the PEP-II asymmetric-energy e^{+}e^{-} collider at the SLAC National Accelerator Laboratory
Search For New Physics at BABAR*
Directory of Open Access Journals (Sweden)
Godang Romulus
2013-05-01
Full Text Available Using a full BABAR data sample of 426 fb−1, we present improved measurements of the ratio ℛ(D(∗ = ℬ(B̅ → D(∗τ−ν̅τ/ ℬ(B̅ → D(∗ℓℓ−ν̅ℓ, where ℓ is either electron or muon. We measure ℛ(D = 0.440±0.058±0.042 and ℛ(D∗ = 0.332±0.024±0.018. These ratios exceed the Standard Model predictions by 2:0σ and 2:7σ, respectively. The results disagree with the Standard Model predictions at the level of 3:4σ. The ratios are sensitive to new physics contributions in the form of a charged Higgs boson. However, the access cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model.
New vertex reconstruction algorithms for CMS
Frühwirth, R; Prokofiev, Kirill; Speer, T.; Vanlaer, P.; Chabanat, E.; Estre, N.
2003-01-01
The reconstruction of interaction vertices can be decomposed into a pattern recognition problem (``vertex finding'') and a statistical problem (``vertex fitting''). We briefly review classical methods. We introduce novel approaches and motivate them in the framework of high-luminosity experiments like at the LHC. We then show comparisons with the classical methods in relevant physics channels
High-resolution hybrid pixel sensors for the e+e- Tesla linear collider vertex tracker
International Nuclear Information System (INIS)
In order to fully exploit the physics potential of a future high-energy e+e- linear collider, a Vertex Tracker, providing high-resolution track reconstruction, is required. Hybrid silicon pixel sensors are an attractive option, for the sensor technology, due to their read-out speed and radiation hardness, favoured in the high-rate environment of the TESLA e+e- linear collider design, but have been so far limited by the achievable single point space resolution. In this paper, a conceptual design of the TESLA Vertex Tracker, based on a novel layout of hybrid pixel sensors with interleaved cells to improve their spatial resolution, is presented
Physics motivation for a 1036 super B Factory and the superBABAR experiment
International Nuclear Information System (INIS)
The search for new physics beyond the Standard Model in the quark sector involves direct searches for new particles (e.g. squarks), indirect searches for new amplitudes in loop processes by testing Standard Model predictions for rare decay branching fractions and decay distributions, and overconstrained tests of CKM matrix. The next generation asymmetric B Factory requires a significant increase in luminosity, approaching 1036 cm-2s-1, well beyond the performance of PEP-II and KEKB. Such luminosity is feasible. Initial parameters of SuperPEP-II, a very high luminosity asymmetric B Factory are being developed, incorporating several new ideas from the successful operation of the present generation accelerators. Doing a precision experiment requires an upgraded detector to cope with backgrounds and radiation levels. Studies at Snowmass indicate that this is tractable. There appears to be a feasible upgrade path from the existing BABAR detector. The existing 1.5 T superconducting solenoid and flux return would be retained, as well as the instrumented flux return detectors, which will be upgraded in several years. The electromagnetic calorimeter would be based on scintillation light from liquid xenon. The vertex measurement and tracking would be done by a combination of two pixel detector layers and approximately seven double-sided strip layers. The DIRC particle identification system would be rebuilt to reduce background. R and D efforts on liquid xenon scintillation calorimetry and on a new readout scheme for the DIRC are underway. The measurement precision on CP-violating quantities assumes detector performance comparable to that currently obtained at BABAR or Belle. With new technology, it is not only possible to cope with the increased rates and backgrounds but also to improve performance in specific areas that can further improve the quality of several important measurements. The program has many unique aspects and is complementary to the programs at hadronic
Proposal for a CLEO precision vertex detector
International Nuclear Information System (INIS)
Fermilab experiment E691 and CERN experiment NA32 have demonstrated the enormous power of precision vertexing for studying heavy quark physics. Nearly all collider experiments now have or are installing precision vertex detectors. This is a proposal for a precision vertex detector for CLEO, which will be the pre-eminent heavy quark experiment for at least the next 5 years. The purpose of a precision vertex detector for CLEO is to enhance the capabilities for isolating B, charm, and tau decays and to make it possible to measure the decay time. The precision vertex detector will also significantly improve strange particle identification and help with the tracking. The installation and use of this detector at CLEO is an important step in developing a vertex detector for an asymmetric B factory and therefore in observing CP violation in B decays. The CLEO environment imposes a number of unique conditions and challenges. The machine will be operating near the γ (4S) in energy. This means that B's are produced with a very small velocity and travel a distance about 1/2 that of the expected vertex position resolution. As a consequence B decay time information will not be useful for most physics. On the other hand, the charm products of B decays have a higher velocity. For the long lived D+ in particular, vertex information can be used to isolate the charm particle on an event-by-event basis. This helps significantly in reconstructing B's. The vertex resolution for D's from B's is limited by multiple Coulomb scattering of the necessarily rather low momentum tracks. As a consequence it is essential to minimize the material, as measured in radiation lengths, in the beam pip and the vertex detector itself. It is also essential to build the beam pipe and detector with the smallest possible radius
Configuration Database for BaBar On-line
Bartoldus, R.; Dubois-Felsmann, G.; Kolomensky, Y.; Salnikov, A.
2003-01-01
The configuration database is one of the vital systems in the BaBar on-line system. It provides services for the different parts of the data acquisition system and control system, which require run-time parameters. The original design and implementation of the configuration database played a significant role in the successful BaBar operations since the beginning of experiment. Recent additions to the design of the configuration database provide better means for the management of data and add ...
Upgrade of the LHCb Vertex Locator
Leflat, A.
2014-08-01
The upgrade of the LHCb experiment, planned for 2018, will transform the entire readout to a trigger-less system operating at 40 MHz. All data reduction algorithms will be executed in a high-level software farm, with access to all event information. This will enable the detector to run at luminosities of 1-2 × 1033/cm2/s and probe physics beyond the Standard Model in the heavy sector with unprecedented precision. The upgraded VELO must be low mass, radiation hard and vacuum compatible. It must be capable of fast pattern recognition and track reconstruction and will be required to drive data to the outside world at speeds of up to 2.5 Tbit/s. This challenge is being met with a new Vertex Locator (VELO) design based on hybrid pixel detectors positioned to within 5 mm of the LHC colliding beams. The sensors have 55 × 55 μm square pixels and the VELOPix ASIC which is being developed for the readout is based on the Timepix/Medipix family of chips. The hottest ASIC will have to cope with pixel hit rates of up to 900 MHz. The material budget will be optimised with the use of evaporative CO2 coolant circulating in microchannels within a thin silicon substrate. Microchannel cooling brings many advantages: very efficient heat transfer with almost no temperature gradients across the module, no CTE mismatch with silicon components, and low material contribution. This is a breakthrough technology being developed for LHCb. LHCb is also focussing effort on the construction of a lightweight foil to separate the primary and secondary LHC vacua, the development of high speed cables and radiation qualification of the module. The 40 MHz readout will also bring significant conceptual changes to the way in which the upgrade trigger is operated. Work is in progress to incorporate momentum and impact parameter information into the trigger at the earliest possible stage, using the fast pattern recognition capabilities of the upgraded detector. The current status of the VELO upgrade will
Energy Technology Data Exchange (ETDEWEB)
Baracchini, Elisabetta; /Rome U. /INFN, Rome
2011-11-10
We will present the most recent results on leptonic B decays B{sup {+-}(0)} {yields} K*{sup {+-}(0)}{nu}{bar {nu}} and B{sup {+-}} {yields} {mu}{sup {+-}}{nu}, based on the data collected by the BaBar detector at PEP-II, an asymmetric e{sup +}e{sup -} collider at the center of mass energy of the {Upsilon}(4S) resonance. Rare B decays have always been a standard probe for New Physics (NP) searches. The very low Standard Model (SM) rate of these decays often make them unaccessible with the present experimental datasets, unless NP effects enhance the rate up to the current experimental sensitivity. Moreover, as NP effects can modify the decay kinematic, particular attention must be paid in order to perform a model independent analysis. A B-Factory provides an unique environment to investigate these processes. The high number of B{bar B} pairs produced by a B-Factory often allows to approach the needed experimental sensitivity. Moreover, the clean environment and the closed kinematic of the initial state enable to obtaining a very pure sample where to look for these decays.
Energy Technology Data Exchange (ETDEWEB)
Monorchio, Diego; /INFN, Naples /Naples U.
2011-09-13
The authors will present the most recent results on leptonic B decays B{sup {+-}(0)} {yields} K*{sup {+-}(0)} {nu}{bar {nu}} and B{sup {+-}} {yields} {mu}{sup {+-}}{nu}, based on the data collected by the BaBar detector at PEP-II, an asymmetric e{sup +}e{sup -} collider at the center of mass energy of the {Upsilon}(4S) resonance. Rare B decays have always been a standard probe for New Physics (NP) searches. The very low Standard Model (SM) rate of these decays often make them unaccessible with the present experimental datasets, unless NP effects enhance the rate up to the current experimental sensitivity. Moreover, as NP effects can modify the decay kinematic, particular attention must be payed in order to perform a model independent analysis. A B-Factory provides an unique environment where to investigate these processes. The high number of B{bar B} pairs produced by a B-Factory often allows to approach the needed experimental sensitivity. Moreover, the clean environment and the closed kinematic of the initial state enable to obtaining a very pure sample where to look for these decays.
The BABAR database: challenges, trends and projections
International Nuclear Information System (INIS)
The BABAR database, based upon the Objectivity OO database management system, has been in production since early 1999. It has met its initial design requirements which were to accommodate a 100Hz event rate from the experiment at a scale of 200TB per year. However, with increased luminosity and changes in the physics requirements, these requirements have increased significantly for the current running period and will again increase in the future. New capabilities in the underlying ODBMS product, in particular those of multiple federation and read-only database support, have been incorporated into a new design that is backwards compatible with existing application code while offering scaling into the multi-petabyte size regime. Other optimizations, including the increased use of tightly coupled CORBA servers and an improved awareness of space inefficiencies, are also playing a part in meeting the new scaling requirements. The authors discuss these optimizations and the prospects for further scaling enhancements to address the longer-term needs of the experiment
The BABAR Database: Challenges, Trends and Projections
International Nuclear Information System (INIS)
The BABAR database, based upon the Objectivity OO database management system, has been in production since early 1999. It has met its initial design requirements which were to accommodate a 100Hz event rate from the experiment at a scale of 200TB per year. However, with increased luminosity and changes in the physics requirements, these requirements have increased significantly for the current running period and will again increase in the future. New capabilities in the underlying ODBMS product, in particular those of multiple federation and read-only database support, have been incorporated into a new design that is backwards compatible with existing application code while offering scaling into the multi-petabyte size regime. Other optimizations, including the increased use of tightly coupled CORBA servers and an improved awareness of space inefficiencies, are also playing a part in meeting the new scaling requirements. We discuss these optimizations and the prospects for further scaling enhancements to address the longer-term needs of the experiment
International Nuclear Information System (INIS)
The most recent results obtained by the BABAR experiment at the PEP-II asymmetric-energy B Factory at SLAC on CP-violating asymmetries and branching fractions for neutral and charged B decays are presented here. The analysis was performed on a data sample of ∼ 88 million Υ(4S) → B(bar B) decays collected between 1999 and 2002. Using b → c(bar c)s decays, we measure sin2β = 0.741 ± 0.067(stat) ± 0.034(syst). We also present sin2β measurements from, b → s(bar s)s and b → c(bar c)d processes. From neutral B meson decays to two-body final states of charged pions and kaons, we derive for the CP violating parameters, Sππ = 0.02 ± 0.34 ± 0.05 [-0.54, +0.58] and Cππ = -0.30 ± 0.25 ± 0.04 [-0.72, +0.12]. First results for B → π+π-π0 and K±π±π0 final states dominated by the ρ± resonance, are also presented
Berry, M
2003-01-01
The Instrumented Flux Return (IFR) of the BaBar detector will soon need to be replaced by a more robust muon detection system. Scintillator bars with embedded Wavelength Shifting (WLS) fibers and Limited Streamer Tubes are two replacement technology options. The scintillator bars are tested for attenuation length; and causes for the large width of the Photo Multiplier Tube (PMT) signal are analyzed by Monte Carlo simulation. Cooling techniques for Avalanche Photo Diodes (APD) are investigated. The fairly high attenuation length coupled with the narrow PMT signal make the scintillator a viable option for a muon detecting system. Continuing work will focus on increasing timing resolution using an APD to read the signal from the WLS fibers, and investigating the lifetime of the APD. The ability to read a signal from the LST on external copper strips is tested and signals are found to be clearly distinguishable from noise. The voltage is compared to count rate to find that the optimal operating voltage for the LS...
International Nuclear Information System (INIS)
The Instrumented Flux Return (IFR) of the BaBar detector will soon need to be replaced by a more robust muon detection system. Scintillator bars with embedded Wavelength Shifting (WLS) fibers and Limited Streamer Tubes are two replacement technology options. The scintillator bars are tested for attenuation length; and causes for the large width of the Photo Multiplier Tube (PMT) signal are analyzed by Monte Carlo simulation. Cooling techniques for Avalanche Photo Diodes (APD) are investigated. The fairly high attenuation length coupled with the narrow PMT signal make the scintillator a viable option for a muon detecting system. Continuing work will focus on increasing timing resolution using an APD to read the signal from the WLS fibers, and investigating the lifetime of the APD. The ability to read a signal from the LST on external copper strips is tested and signals are found to be clearly distinguishable from noise. The voltage is compared to count rate to find that the optimal operating voltage for the LST used is 4600V. Further studies will be conducted in strip readout and fabrication as well as in the optimal isobutane content in the gas mixture that flows through the tube
Quantum Algebraic Approach to Refined Topological Vertex
Awata, H; Shiraishi, J
2011-01-01
We establish the equivalence between the refined topological vertex of Iqbal-Kozcaz-Vafa and a certain representation theory of the quantum algebra of type W_{1+infty} introduced by Miki. Our construction involves trivalent intertwining operators Phi and Phi^* associated with triples of the bosonic Fock modules. Resembling the topological vertex, a triple of vectors in Z^2 is attached to each intertwining operator, which satisfy the Calabi-Yau and smoothness conditions. It is shown that certain matrix elements of Phi and Phi^* give the refined topological vertex C_{lambda mu nu}(t,q) of Iqbal-Kozcaz-Vafa. With another choice of basis, we recover the refined topological vertex C_{lambda mu}^nu(q,t) of Awata-Kanno. The gluing factors appears correctly when we consider any compositions of Phi and Phi^*. The spectral parameters attached to Fock spaces play the role of the K"ahler parameters.
The Perfect Quark-Gluon Vertex Function
Orginos, K; Brower, Richard C; Chandrasekharan, S; Wiese, U J
1998-01-01
We evaluate a perfect quark-gluon vertex function for QCD in coordinate space and truncate it to a short range. We present preliminary results for the charmonium spectrum using this quasi-perfect action.
Fast Vertex Guarding for Polygons
King, James
2011-01-01
For a polygon P with n vertices, the vertex guarding problem asks for the minimum subset G of P's vertices such that every point in P is seen by at least one point in G. This problem is NP-complete and APX-hard. The first approximation algorithm (Ghosh, 1987) involves decomposing P into O(n^4) cells that are equivalence classes for visibility from the vertices of P. This discretized problem can then be treated as an instance of set cover and solved in O(n^5) time with a greedy O(log n)-approximation algorithm. Ghosh (2010) recently revisited the algorithm, noting that minimum visibility decompositions for simple polygons (Bose et al., 2000) have only O(n^3) cells, improving the running time of the algorithm to O(n^4) for simple polygons. In this paper we show that, since minimum visibility decompositions for simple polygons have only O(n^2) cells of minimal visibility (Bose et al., 2000), the running time of the algorithm can be further improved to O(n^3). We extend the result of Bose et al. to polygons with ...
Generalized vertex coloring problems using split graphs
Ekim, Tinaz; de Werra, Dominique
2007-01-01
Graph theory experienced a remarkable increase of interest among the scientific community during the last decades. The vertex coloring problem (Min Coloring) deserves a particular attention rince it has been able to capture a wide variety of applications. For mathematicians, it is interesting for an additional reason: it is extremely hard to solve it in an efficient way. In this thesis, we introduce several problems generalizing the usual vertex coloring problem, and hence, extending its appl...
Generalized vertex coloring problems using split graphs
Ekim, Tinaz
2006-01-01
Graph theory experienced a remarkable increase of interest among the scientific community during the last decades. The vertex coloring problem (Min Coloring) deserves a particular attention rince it has been able to capture a wide variety of applications. For mathematicians, it is interesting for an additional reason: it is extremely hard to solve it in an efficient way. In this thesis, we introduce several problems generalizing the usual vertex coloring problem, and hence, extending its appl...
Twisted Logarithmic Modules of Vertex Algebras
Bakalov, Bojko
2016-07-01
Motivated by logarithmic conformal field theory and Gromov-Witten theory, we introduce a notion of a twisted module of a vertex algebra under an arbitrary (not necessarily semisimple) automorphism. Its main feature is that the twisted fields involve the logarithm of the formal variable. We develop the theory of such twisted modules and, in particular, derive a Borcherds identity and commutator formula for them. We investigate in detail the examples of affine and Heisenberg vertex algebras.
Performance, radiation damage effects and upgrade of the LHCB vertex locator
Energy Technology Data Exchange (ETDEWEB)
Capua, Stefano de, E-mail: stefano.decapua@hep.manchester.co.uk
2013-12-21
LHCb is a dedicated experiment to study new physics in the decays of heavy hadrons at the Large Hadron Collider (LHC) at CERN. Heavy hadrons are identified through their flight distance in the Vertex Locator (VELO), the retractable silicon-strip vertex detector surrounding the LHCb interaction point at only 8 mm from the beam during normal LHC operation. The VELO consists of a series of silicon micro-strip detectors and operates in an extreme and highly non-uniform radiation environment. The performance of the LHCb VELO during the first three years of LHC physics running and the primary results from radiation damage studies are presented. Plans for an upgraded detector by 2018 with a 40 MHz readout are also presented.
The BaBar instrumented flux return performance: lessons learned
Anulli, F; Baldini, R; Band, H R; Bionta, R; Brau, J E; Brigljevic, V; Buzzo, A; Calcaterra, A; Carpinelli, M; Cartaro, C; Cavallo, N; Crosetti, G; De Nardo, Gallieno; De Sangro, R; Eichenbaum, A; Fabozzi, F; Falciai, D; Ferrarotto, F; Ferroni, F; Finocchiaro, G; Forti, F; Frey, R; Gatto, C; Graug; Iakovlev, N I; Iwasaki, M; Johnson, J R; Lange, D J; Lista, L; Lo Vetere, M; Lü, C; Macri, M; Messner, R; Moore, T B; Morganti, S; Neal, H; Neri, N; Palano, A; Paoloni, E; Paolucci, P; Passaggio, S; Pastore, F C; Patteri, P; Peruzzi, I; Piccolo, D; Piccolo, M; Piredda, G; Robutti, E; Roodman, A; Santroni, A; Sciacca, C; Sinev, N B; Soha, A; Strom, D; Tosi, S; Vavra, J; Wisniewski, W J; Wright, D M; Xie, Y; Zallo, A
2002-01-01
The BaBar Collaboration has operated an instrumented flux return (IFR) system covering over 2000 m sup 2 with resistive plate chambers (RPCs) for nearly 3 years. The chambers are constructed of bakelite sheets separated by 2 mm. The inner surfaces are coated with linseed oil. This system provides muon and neutral hadron detection for BaBar. Installation and commissioning were completed in 1998, and operation began mid-year 1999. While initial performance of the system reached design, over time, a significant fraction of the RPCs demonstrated significant degradation, marked by increased currents and reduced efficiency. A coordinated effort of investigations have identified many of the elements responsible for the degradation. This article presents our current understanding of the aging process of the BaBar RPCs along with the action plan to combat performance degradation of the IFR system.
The Optical Alignment System of the ZEUS MicroVertex Detector
Korcsak-Gorzo, K.; Grzelak, G.; Oliver, K.; Dawson, M; Devenish, R.; Ferrando, J.; Matsushita, T.; P. Shield; Walczak, R.
2008-01-01
The laser alignment system of the ZEUS microvertex detector is described. The detector was installed in 2001 as part of an upgrade programme in preparation for the second phase of electron-proton physics at the HERA collider. The alignment system monitors the position of the vertex detector support structure with respect to the central tracking detector using semi-transparent amorphous-silicon sensors and diode lasers. The system is fully integrated into the general environmental monitoring o...
Displaced vertex searches for sterile neutrinos at future lepton colliders
Antusch, Stefan; Fischer, Oliver
2016-01-01
We investigate the sensitivity of future lepton colliders to displaced vertices from the decays of long-lived heavy (almost sterile) neutrinos with electroweak scale masses and detectable time of flight. As future lepton colliders we consider the FCC-ee, the CEPC, and the ILC, searching at the Z-pole and at the center-of-mass energies of 240, 350 and 500 GeV. For a realistic discussion of the detector response to the displaced vertex signal and the Standard Model background we consider the ILC's Silicon Detector (SiD) as benchmark for the future lepton collider detectors. We find that displaced vertices constitute a powerful search channel for sterile neutrinos, sensitive to squared active-sterile mixing angles as small as $10^{-11}$.
MEG II drift chamber characterization with the silicon based cosmic ray tracker at INFN Pisa
Venturini, M.; Baldini, A. M.; Baracchini, E.; Cei, F.; D`Onofrio, A.; Dussoni, S.; Galli, L.; Grassi, M.; Nicolò, D.; Signorelli, G.
2016-07-01
High energy physics experiments at the high intensity frontier place ever greater demands on detectors, and in particular on tracking devices. In order to compare the performance of small size tracking prototypes, a high resolution cosmic ray tracker has been assembled to provide an external track reference. It consists of four spare ladders of the external layers of the Silicon Vertex Tracker of the BaBar experiment. The test facility, operating at INFN Sezione di Pisa, provides the detector under test with an external track with an intrinsic resolution of 15-30 μm. The MEG II tracker is conceived as a unique volume wire drift chamber filled with He-isobutane 85-15%. The ionization density in this gas mixture is about 13 clusters/cm and this results in a non-negligible bias of the impact parameters for tracks crossing the cell close to the anode wire. We present the telescope performance in terms of tracking efficiency and resolution and the results of the characterization of a MEG II drift chamber prototype.
International Nuclear Information System (INIS)
The BABAR high energy physics experiment has been designed to study CP violation in the neutral B meson system. Data-taking began at the PEP-II asymmetric e+e- collider in Spring 1999. The B-physics program for BABAR involves the reconstruction of the wide range of exclusive final states needed for CP studies. This places stringent requirements on the performance of the detector. Since many of the modes of interest include π0 s, it is essential to achieve excellent energy and position resolution for the CsI(Tl) electromagnetic calorimeter. CsI(Tl) crystals for the BABAR electromagnetic calorimeter were supplied by several manufacturing companies. Collaborative work was undertaken with one of these companies, Hilger Crystal Materials, to ensure that the crystals met the high specifications required by BABAR. A new production process was established in order to generate the large size and number of CsI(Tl) crystals needed. The resulting change of scale (larger furnaces, extended growth/cooling periods, increased mass/material handling) presented considerable challenges for all aspects of the production environment in order to achieve the necessary production rate and quality of crystals. The existing working practices were assessed and redesigned to suite the BABAR crystal production. A new purpose-built quality assurance (QA) testing laboratory at Hilger was created, where the trapezoidal crystals were to be precisely dimensioned, tuned for light output, and wrapped. Specialised QA instrumentation was needed for BABAR crystals, and this was built locally, based on a design from SLAC. The operational procedures for quality assurance were established, and new staff were trained in these procedures. The unique characteristics of Hilger crystals required the careful design of tuning methods to optimise light uniformity and overall light yield. Detailed studies of factors affecting crystal properties were carried out, including effects of furnace temperature gradients
Search for the Z(4430) at BABAR
Energy Technology Data Exchange (ETDEWEB)
Aubert, B.
2009-01-12
We report the results of a search for Z(4430){sup -} decay to J/{psi}{pi}{sup -} or {psi}(2S){pi}{sup -} in B{sup -,0} {yields} J/{psi}{pi}{sup -} K{sup 0,+} and B{sup -,0} {yields} {psi}(2S){pi}{sup -}K{sup 0,+} decays. The data were collected with the BABAR detector at the SLAC PEP-II asymmetric-energy e{sup +}e{sup -} collider operating at center of mass energy 10.58 GeV, and the sample corresponds to an integrated luminosity of 413 fb{sup -1}. Each K{pi}{sup -} mass distribution exhibits clear K*(892) and K*{sub 2}(1430) signals, and the efficiency-corrected spectrum is well-described by a superposition of the associated Breit-Wigner intensity distributions, together with an S-wave contribution obtained from the LASS I = 1/2 K{pi}{sup -} scattering amplitude measurements. Each K{pi}{sup -} angular distribution varies significantly in structure with K{pi}{sup -} mass, and is represented in terms of low-order Legendre polynomial moments. We find that each J/{psi}{pi}{sup -} or {psi}(2S){pi}{sup -} mass distribution is well-described by the reflection of the measured K{pi}{sup -} mass and angular distribution structures. We see no significant evidence for a Z(4430){sup -} signal for any of the processes investigated, neither in the total J/{psi}{pi}{sup -} or {psi}(2S){pi}{sup -} mass distribution, nor in the corresponding distributions for the regions of K{pi}{sup -} mass for which observation of the Z(4430){sup -} signal was reported. We obtain branching fraction upper limits {Beta}(B{sup -} {yields} Z{sup -}{bar K}{sup 0}, Z{sup -} {yields} J/{psi}{pi}{sup -}) < 1.5 x 10{sup -5}, {Beta}(B{sup 0} {yields} Z{sup -}K{sup +},Z{sup -} {yields} J/{psi}{pi}{sup -}) < 0.4 x 10{sup -5}, {Beta}(B{sup -} {yields} Z{sup -} {bar K}{sup 0}, Z{sup -} {yields} {psi}(2S){pi}{sup -}) > 4.7 x 10{sup -5}, and {Beta}(B{sup 0} {yields} Z{sup -} K{sup +}, Z{sup -} {yields} {psi}(2S){pi}{sup -}) < 3.1 x 10{sup -5} at 95% confidence level, where the Z(4430){sup -} mass and width have
Trace Identities for the Topological Vertex
Bryan, Jim; Young, Benjamin
2016-01-01
The topological vertex is a universal series which can be regarded as an object in combinatorics, representation theory, geometry, or physics. It encodes the combinatorics of 3D partitions, the action of vertex operators on Fock space, the Donaldson-Thomas theory of toric Calabi-Yau threefolds, or the open string partition function of $\\mathbb{C}^3$. We prove several identities in which a sum over terms involving the topological vertex is expressed as a closed formula, often a product of simple terms, closely related to Fourier expansions of Jacobi forms. We use purely combinatorial and representation theoretic methods to prove our formulas, but we discuss applications to the Donaldson-Thomas invariants of elliptically fibered Calabi-Yau threefolds at the end of the paper.
A note on arbitrarily vertex decomposable graphs
Directory of Open Access Journals (Sweden)
Antoni Marczyk
2006-01-01
Full Text Available A graph \\(G\\ of order \\(n\\ is said to be arbitrarily vertex decomposable if for each sequence \\((n_{1},\\ldots,n_k\\ of positive integers such that \\(n_{1}+\\ldots+n_{k}=n\\ there exists a partition \\((V_{1},\\ldots,V_{k}\\ of the vertex set of \\(G\\ such that for each \\(i \\in \\{1,\\ldots,k\\}\\, \\(V_{i}\\ induces a connected subgraph of \\(G\\ on \\(n_i\\ vertices. In this paper we show that if \\(G\\ is a two-connected graph on \\(n\\ vertices with the independence number at most \\(\\lceil n/2\\rceil\\ and such that the degree sum of any pair of non-adjacent vertices is at least \\(n-3\\, then \\(G\\ is arbitrarily vertex decomposable. We present another result for connected graphs satisfying a similar condition, where the bound \\(n-3\\ is replaced by \\(n-2\\.
Open string amplitudes of closed topological vertex
Takasaki, Kanehisa
2016-01-01
The closed topological vertex is the simplest "off-strip" case of non-compact toric Calabi-Yau threefolds with acyclic web diagrams. By the diagrammatic method of topological vertex, open string amplitudes of topological string theory therein can be obtained by gluing a single topological vertex to an "on-strip" subdiagram of the tree-like web diagram. If non-trivial partitions are assigned to just two parallel external lines of the web diagram, the amplitudes can be calculated with the aid of techniques borrowed from the melting crystal models. These amplitudes are thereby expressed as matrix elements, modified by simple prefactors, of an operator product on the Fock space of 2D charged free fermions. This fermionic expression can be used to derive $q$-difference equations for generating functions of special subsets of the amplitudes. These $q$-difference equations may be interpreted as the defining equation of a quantum mirror curve.
Vertex Operators and Moduli Spaces of Sheaves
Carlsson, Erik
2009-01-01
The Nekrasov partition function in supersymmetric quantum gauge theory is mathematically formulated as an equivariant integral over certain moduli spaces of sheaves on a complex surface. In ``Seiberg-Witten Theory and Random Partitions'', Nekrasov and Okounkov studied these integrals using the representation theory of ``vertex operators'' and the infinite wedge representation. Many of these operators arise naturally from correspondences on the moduli spaces, such as Nakajima's Heisenberg operators, and Grojnowski's vertex operators. In this paper, we build a new vertex operator out of the Chern class of a vector bundle on a pair of moduli spaces. This operator has the advantage that it connects to the partition function by definition. It also incorporates the canonical class of the surface, whereas many other studies assume that the class vanishes. When the moduli space is the Hilbert scheme, we present an explicit expression in the Nakajima operators, and the resulting combinatorial identities. We then apply...
Open string amplitudes of closed topological vertex
International Nuclear Information System (INIS)
The closed topological vertex is the simplest ‘off-strip’ case of non-compact toric Calabi–Yau threefolds with acyclic web diagrams. By the diagrammatic method of topological vertex, open string amplitudes of topological string theory therein can be obtained by gluing a single topological vertex to an ‘on-strip’ subdiagram of the tree-like web diagram. If non-trivial partitions are assigned to just two parallel external lines of the web diagram, the amplitudes can be calculated with the aid of techniques borrowed from the melting crystal models. These amplitudes are thereby expressed as matrix elements, modified by simple prefactors, of an operator product on the Fock space of 2D charged free fermions. This fermionic expression can be used to derive q-difference equations for generating functions of special subsets of the amplitudes. These q-difference equations may be interpreted as the defining equation of a quantum mirror curve. (paper)
CPLEAR et BABAR, all aspects of CP violation
International Nuclear Information System (INIS)
This report of French 'Habilitation a diriger les recherches' summarizes my scientific activity from 1993 to 2003. During this decade, my research work was related to two particle physics experiments: CPLEAR and BABAR. The first one, CPLEAR, has recorded data from 1988 to 1995 on the low energy anti-proton ring (LEAR) at CERN. This experiment was devoted to the study of T, CPT et CP discrete symmetries. The second experiment, BABAR, has been running since 1999, on the PEP-II B factory at SLAC. This experiment searches for CP violation and tests the Standard Model through the measurements of the angles and the sides of the Unitarity Triangle. My research work is divided in five main topics: Study of CP and CPT violation in K0 → π+ π- decays; Performance optimization of the particle identification detector (DIRC) of the BABAR experiment; B meson tagging in BABAR experiment; Δmd measurement and Search for CP and T violation in mixing with dilepton events; Search for CP violation in B0 → ρ± π± and B0 → π± K± decays. (author)
Studies of radiative penguin B decays at BaBar
Indian Academy of Sciences (India)
John M LoSecco; BaBar Collaboration
2004-03-01
We summarize results on a number of observations of penguin dominated radiative decays of the meson. Such decays are forbidden at tree level and proceed via electroweak loops. As such they may be sensitive to physics beyond the standard model. The observations have been made at the BaBar experiment at PEP-II, the asymmetric factory at SLAC.
On spectral theory of quantum vertex operators
Etingof, Pavel
1994-01-01
In this note we prove the Davies-Foda-Jimbo-Miwa-Nakayashiki conjecture on the asymptotics of the composition of n quantum vertex operators for the quantum affine algebra U_q(\\hat sl_2), as n goes to infinity. For this purpose we define and study the leading eigenvalue and eigenvector of the product of two components of the quantum vertex operator. This eigenvector and the corresponding eigenvalue were recently computed by M.Jimbo. The results of his computation are given in Section 4.
Vertex operators in solvable lattice models
Foda, O E; Miwa, T; Miki, K; Nakayashiki, A; Foda, Omar; Jimbo, Michio; Miwa, Tetsuji; Miki, Kei; Nakayashiki, Atsushi
1994-01-01
We formulate the basic properties of q-vertex operators in the context of the Andrews-Baxter-Forrester (ABF) series, as an example of face-interaction models, derive the q-difference equations satisfied by their correlation functions, and establish their connection with representation theory. We also discuss the q-difference equations of the Kashiwara-Miwa (KM) series, as an example of edge-interaction models. Next, the Ising model--the simplest special case of both ABF and KM series--is studied in more detail using the Jordan-Wigner fermions. In particular, all matrix elements of vertex operators are calculated.
Taxonomy of the sixteen-vertex models
International Nuclear Information System (INIS)
In this paper a classification of the subcases of the sixteen-vertex model compatible with the infinite symmetry group generated by the inversion relations of the model is performed. The elliptic parametrization of these models is recalled, emphasizing the subvarieties of the parameter space for which this parametrization degenerates into a rational one. This situation corresponds to the vanishing of some discriminant and is deeply related to the critical and disorder manifolds for these models. The authors concentrate on subcases of the sixteen-vertex model for which factorizations of this discriminant occur, allowing further exact calculations
Vertex Lie algebras and cyclotomic coinvariants
Vicedo, Benoit; Young, Charles A. S.
2014-01-01
Given a vertex Lie algebra $\\mathscr L$ equipped with an action by automorphisms of a cyclic group $\\Gamma$, we define spaces of cyclotomic coinvariants over the Riemann sphere. These are quotients of tensor products of smooth modules over `local' Lie algebras $\\mathsf L(\\mathscr L)_{z_i}$ assigned to marked points $z_i$, by the action of a `global' Lie algebra ${\\mathsf L}^{\\Gamma}_{\\{z_i \\}}(\\mathscr L)$ of $\\Gamma$-equivariant functions. On the other hand, the universal enveloping vertex a...
Silicon pin diode array hybrids for charged particle detection
International Nuclear Information System (INIS)
This paper reports on the design of silicon PIN diode array hybrids for use as charged particle detectors. A brief summary of the need for vertex detectors is presented. Circuitry, block diagrams and device specifications are included
Optimization of silicon microstrip detector design for CLEO III
International Nuclear Information System (INIS)
We present measurements from prototype silicon microstrip detectors for the CLEO III silicon vertex detector. Noise and capacitance optimization is discussed. We also present a design to achieve 10 pF total capacitance on a double sided, double metal silicon detector. (orig.)
Bounding the Feedback Vertex Number of Digraphs in Terms of Vertex Degrees
Gruber, Hermann
2011-01-01
The Turan bound is a famous result in graph theory, which relates the independence number of an undirected graph to its edge density. Also the Caro-Wei inequality, which gives a more refined bound in terms of the vertex degree sequence of a graph, might be regarded today as a classical result. We show how these statements can be generalized to directed graphs, thus yielding a bound on directed feedback vertex number in terms of vertex outdegrees and in terms of average outdegree, respectively.
Study of a DEPFET vertex detector and of supersymmetric smuons at the ILC
Energy Technology Data Exchange (ETDEWEB)
Chen, Xun
2009-01-21
This thesis is devoted to the study of the performance of a pixel vertex detector based on DEPFET technology at the International Linear Collider (ILC). The ILC is the proposed next generation e{sup +}e{sup -} collider to explore the physics at the Terascale. At the ILC with its well-defined initial state of collisions, possible discoveries at the Large Hadron Collider can be verified and studied more accurately. It is expected that the precision measurements of the ILC will answer many fundamental questions about the universe, such as the generation of particle masses and the origin of electroweak spontaneous symmetry breaking. The ambitious physics goals present challenges to the ILC detectors. Several detector concepts have been proposed in recent years. A crucial device for all these concepts is the pixel vertex detector. It provides precise impact parameter information of charged particles, jet flavor tagging and improves overall tracking efficiency. To meet the requirements of the ILC environment, the vertex detector will be arranged in a concentric multi-layer array around the interaction point to cover as large a solid angle as possible. Endcap disks are considered in some designs. Silicon pixel sensor technologies must be employed to provide excellent point resolution. The DEPFET technology, which integrates the first level of amplification into a depleted silicon bulk, is one of the promising candidates. The DEPFET sensor is very sensitive with a high signal-to-noise ratio. Power consumption is minimized due to the internal storage of signal charges. The good radiation tolerance makes it capable of working close to the interaction point. In this thesis, we discuss the detailed simulation of the DEPFET vertex detector, following the general vertex detector layout proposed by the TESLA collaboration. The simulation is used to evaluate the impact parameter resolution. We also discuss the DEPFET test beam analysis on two-track resolution. The whole analysis
Study of a DEPFET vertex detector and of supersymmetric smuons at the ILC
International Nuclear Information System (INIS)
This thesis is devoted to the study of the performance of a pixel vertex detector based on DEPFET technology at the International Linear Collider (ILC). The ILC is the proposed next generation e+e- collider to explore the physics at the Terascale. At the ILC with its well-defined initial state of collisions, possible discoveries at the Large Hadron Collider can be verified and studied more accurately. It is expected that the precision measurements of the ILC will answer many fundamental questions about the universe, such as the generation of particle masses and the origin of electroweak spontaneous symmetry breaking. The ambitious physics goals present challenges to the ILC detectors. Several detector concepts have been proposed in recent years. A crucial device for all these concepts is the pixel vertex detector. It provides precise impact parameter information of charged particles, jet flavor tagging and improves overall tracking efficiency. To meet the requirements of the ILC environment, the vertex detector will be arranged in a concentric multi-layer array around the interaction point to cover as large a solid angle as possible. Endcap disks are considered in some designs. Silicon pixel sensor technologies must be employed to provide excellent point resolution. The DEPFET technology, which integrates the first level of amplification into a depleted silicon bulk, is one of the promising candidates. The DEPFET sensor is very sensitive with a high signal-to-noise ratio. Power consumption is minimized due to the internal storage of signal charges. The good radiation tolerance makes it capable of working close to the interaction point. In this thesis, we discuss the detailed simulation of the DEPFET vertex detector, following the general vertex detector layout proposed by the TESLA collaboration. The simulation is used to evaluate the impact parameter resolution. We also discuss the DEPFET test beam analysis on two-track resolution. The whole analysis procedures
High-resolution hybrid pixel sensors for the e sup + e sup - Tesla linear collider vertex tracker
Battaglia, Marco; Tammi, K; Österberg, K; Kucewicz, W; Zalewska-Bak, A; Caccia, M; Campagnolo, R; Meroni, C; Grabiec, P; Jaroszewicz, B; Marczewski, J
2000-01-01
In order to fully exploit the physics potential of a future high-energy e sup + e sup - linear collider, a Vertex Tracker, providing high-resolution track reconstruction, is required. Hybrid silicon pixel sensors are an attractive option, for the sensor technology, due to their read-out speed and radiation hardness, favoured in the high-rate environment of the TESLA e sup + e sup - linear collider design, but have been so far limited by the achievable single point space resolution. In this paper, a conceptual design of the TESLA Vertex Tracker, based on a novel layout of hybrid pixel sensors with interleaved cells to improve their spatial resolution, is presented.
The Micro-Vertex-Detector for the P-bar ANDA experiment
International Nuclear Information System (INIS)
P-bar ANDA is a fixed target experiment that will be carried out at the future FAIR facility. P-bar ANDA will provide an excellent tool to address fundamental question in the field of hadronic physics, with a physic program that extends from the investigation of QCD (providing insight in the mechanisms of mass generation and confinement) to the test of fundamental symmetries. The Micro-Vertex-Detector located in the innermost part of the central tracking system will be composed by hybrid pixel and double-sided micro-strip silicon detectors. The Micro-Vertex-Detector will play an important role for the P-bar ANDA physics goals. The possibility to reconstruct the secondary vertices and the applicability of a precise D meson tagging is essential for the spectroscopy in the open charm sector and the charmonium mass region. To this aim the Micro-Vertex-Detector features a spatial resolution better than 100μm, a time resolution better than 20ns, a limited material budget, and a high data rate capability in a triggerless environment. An overview of the Micro-Vertex-Detector related to the physics goals will be presented.
CPLEAR et BABAR, all aspects of CP violation; CPLEAR et BABAR la violation de CP dans tous ses etats
Energy Technology Data Exchange (ETDEWEB)
Yeche, Ch
2003-06-01
This report of French 'Habilitation a diriger les recherches' summarizes my scientific activity from 1993 to 2003. During this decade, my research work was related to two particle physics experiments: CPLEAR and BABAR. The first one, CPLEAR, has recorded data from 1988 to 1995 on the low energy anti-proton ring (LEAR) at CERN. This experiment was devoted to the study of T, CPT et CP discrete symmetries. The second experiment, BABAR, has been running since 1999, on the PEP-II B factory at SLAC. This experiment searches for CP violation and tests the Standard Model through the measurements of the angles and the sides of the Unitarity Triangle. My research work is divided in five main topics: Study of CP and CPT violation in K{sup 0} {yields} {pi}{sup +} {pi}{sup -} decays; Performance optimization of the particle identification detector (DIRC) of the BABAR experiment; B meson tagging in BABAR experiment; {delta}m{sub d} measurement and Search for CP and T violation in mixing with dilepton events; Search for CP violation in B{sup 0} {yields} {rho}{sup {+-}} {pi}{sup {+-}} and B{sup 0} {yields} {pi}{sup {+-}} K{sup {+-}} decays. (author)
Framed vertex operator algebras, codes and the moonshine module
Dong, C.; Griess Jr., R. L.; Hoehn, G.
1997-01-01
For a simple vertex operator algebra whose Virasoro element is a sum of commutative Virasoro elements of central charge 1/2, two codes are introduced and studied. It is proved that such vertex operator algebras are rational. For lattice vertex operator algebras and related ones, decompositions into direct sums of irreducible modules for the product of the Virasoro algebras of central charge 1/2 are explicitly described. As an application, the decomposition of the moonshine vertex operator alg...
Virasoro Correlation Functions for Vertex Operator Algebras
Hurley, Donny; Tuite, Michael P.
2011-01-01
We consider all genus zero and genus one correlation functions for the Virasoro vacuum descendants of a vertex operator algebra. These are described in terms of explicit generating functions that can be combinatorially expressed in terms of graph theory related to derangements in the genus zero case and to partial permutations in the genus one case.
Flop invariance of the topological vertex
Konishi, Yukiko; Minabe, Satoshi
2006-01-01
We prove transformation formulae for generating functions of Gromov-Witten invariants on general toric Calabi-Yau threefolds under flops. Our proof is based on a combinatorial identity on the topological vertex and analysis of fans of toric Calabi-Yau threefolds.
(q, t) identities and vertex operators
Iqbal, Amer; Qureshi, Babar A.; Shabbir, Khurram
2016-03-01
Using vertex operators acting on fermionic Fock space we prove certain identities, which depend on a number of parameters, generalizing and refining the Nekrasov-Okounkov identity. These identities provide exact product representation for the instanton partition function of certain five-dimensional quiver gauge theories. This product representation also clearly displays the modular transformation properties of the gauge theory partition function.
Gevorkov, L G; CERN. Geneva; Laptev, V D; Patarakin, O O; Valiev, F F
1992-01-01
We discuss the possible application of large area microchannel plates (MCPs) as a basic Abstract: element of a vertex detector unit. Two types of basic modules : (MCP + Delay Line) and (MCP + Microstrips) are suggested. The proposal exploits unique MCPàs features i.e. fine granularity, high intrinsic gain, high counting rates, good performance in the presence of a magnetic field.
New Solution of Vertex Type Tetrahedron Equations
Mangazeev, V. V.; Sergeev, S. M.; Stroganov, Yu. G.
In this letter we formulate a new N-state spin integrable model on a three-dimensional lattice with spins interacting round each elementary cube of the lattice. This model can also be reformulated as a vertex type model. Weight functions of the model satisfy tetrahedron equations.
A Cubic Kernel for Feedback Vertex Set
Bodlaender, H.L.
2006-01-01
The FEEDBACK VERTEX SET problem on unweighted, undirected graphs is considered. Improving upon a result by Burrage et al. [7], we show that this problem has a kernel with O(κ3) vertices, i.e., there is a polynomial time algorithm, that given a graph G and an integer κ, finds a graph G' and integer κ
Status and upgrade of the LHCb Vertex Locator
Gersabeck, M.
2014-06-01
The LHCb Vertex Locator (VELO) is the detector responsible for the detection of heavy hadrons through their flight distance. The performance of the VELO during its three years of operation during the LHC physics runs is presented, focussing on the latest studies. The primary results presented are the first observation of type-inversion at the LHC; a comparison of n-type and p-type silicon in operation; and the observation of a radiation-induced charge loss effect due to the presence of a second metal layer. The upgrade of the LHCb experiment, planned for 2018, will transform the entire readout to a trigger-less system operating at 40 MHz. The upgraded VELO must be light weight, radiation hard, and compatible with LHC vacuum requirements. The material budget will be optimised with the use of evaporative CO2 coolant circulating in micro-channels within a thin silicon substrate. The current status of the VELO upgrade will be described together with a presentation of recent test results, and a discussion of the R&D on alternative solutions which has been carried out within the LHCb VELO upgrade programme.
Some Results on Incremental Vertex Cover Problem
Dai, Wenqiang
In the classical k-vertex cover problem, we wish to find a minimum weight set of vertices that covers at least k edges. In the incremental version of the k-vertex cover problem, we wish to find a sequence of vertices, such that if we choose the smallest prefix of vertices in the sequence that covers at least k edges, this solution is close in value to that of the optimal k-vertex cover solution. The maximum ratio is called competitive ratio. Previously the known upper bound of competitive ratio was 4α, where α is the approximation ratio of the k-vertex cover problem. And the known lower bound was 1.36 unless P = NP, or 2 - ɛ for any constant ɛ assuming the Unique Game Conjecture. In this paper we present some new results for this problem. Firstly we prove that, without any computational complexity assumption, the lower bound of competitive ratio of incremental vertex cover problem is φ, where φ=sqrt{5}+1/2≈ 1.618 is the golden ratio. We then consider the restricted versions where k is restricted to one of two given values(Named 2-IVC problem) and one of three given values(Named 3-IVC problem). For 2-IVC problem, we give an algorithm to prove that the competitive ratio is at most φα. This incremental algorithm is also optimal for 2-IVC problem if we are permitted to use non-polynomial time. For the 3-IVC problem, we give an incremental algorithm with ratio factor (1+sqrt{2})α.
Energy Technology Data Exchange (ETDEWEB)
Battaglia, Marco; Bussat, Jean-Marie; Contarato, Devis; Denes,Peter; Glesener, Lindsay; Greiner, Leo; Hooberman, Benjamin; Shuman,Derek; Tompkins, Lauren; Vu, Chinh; Bisello, Dario; Giubilato, Piero; Pantano, Devis; Costa, Marco; La Rosa, Alessandro; Bolla, Gino; Bortoletto, Daniela; Children, Isaac
2007-10-01
This document summarizes past achievements, current activities and future goals of the R&D program aimed at the design, prototyping and characterization of a full detector module, equipped with monolithic pixel sensors, matching the requirements for the Vertex Tracker at the ILC. We provide a plan of activities to obtain a demonstrator multi-layered vertex tracker equipped with sensors matching the ILC requirements and realistic lightweight ladders in FY11, under the assumption that ILC detector proto-collaborations will be choosing technologies and designs for the Vertex Tracker by that time. The R&D program discussed here started at LBNL in 2004, supported by a Laboratory Directed R&D (LDRD) grant and by funding allocated from the core budget of the LBNL Physics Division and from the Department of Physics at UC Berkeley. Subsequently additional funding has been awarded under the NSF-DOE LCRD program and also personnel have become available through collaborative research with other groups. The aim of the R&D program carried out by our collaboration is to provide a well-integrated, inclusive research effort starting from physics requirements for the ILC Vertex Tracker and addressing Si sensor design and characterization, engineered ladder design, module system issues, tracking and vertex performances and beam test validation. The broad scope of this program is made possible by important synergies with existing know-how and concurrent programs both at LBNL and at the other collaborating institutions. In particular, significant overlaps with LHC detector design, SLHC R&D as well as prototyping for the STAR upgrade have been exploited to optimize the cost per deliverable of our program. This activity is carried out as a collaborative effort together with Accelerator and Fusion Research, the Engineering and the Nuclear Science Divisions at LBNL, INFN and the Department of Physics in Padova, Italy, INFN and the Department of Physics in Torino, Italy and the Department
International Nuclear Information System (INIS)
In LHC Run II, CMS b-tagging algorithms will employ a new core algorithm, named Inclusive Vertex Finder (IVF). The IVF is designed to perform decay vertex reconstruction of long-lived particles, such as B hadrons. Using only tracks from the silicon tracker, it does not depend on jet clustering and allows for higher reconstruction efficiency of decay vertices, which particularly applies to topologies with two or more decay vertices at low distance. Thus, the IVF will offer increased sensitivity for SM measurements (e.g. angular correlations), but also for the search of BSM physics (e.g. final states with boosted Higgs bosons decaying into b-quarks). For the first time, the dependence of the IVF reconstruction efficiency on the distance of vertices in the η-φ plane is investigated with a data-driven approach. We use a clean set of top quark pair events, selected from data recorded in 2012 in pp-collisions at 8 TeV with the CMS detector, and perform a template fit to a 2D-distribution of the masses of the vertices in an event. Correction factors are derived for the application to simulated events. We conclude that our technique will enable precise calibration of double vertexing with the IVF in the LHC Run II.
Energy Technology Data Exchange (ETDEWEB)
Marchesini, Ivan; Nowatschin, Dominik; Ott, Jochen; Schmidt, Alexander; Tholen, Heiner [University of Hamburg (Germany)
2015-07-01
In LHC Run II, CMS b-tagging algorithms will employ a new core algorithm, named Inclusive Vertex Finder (IVF). The IVF is designed to perform decay vertex reconstruction of long-lived particles, such as B hadrons. Using only tracks from the silicon tracker, it does not depend on jet clustering and allows for higher reconstruction efficiency of decay vertices, which particularly applies to topologies with two or more decay vertices at low distance. Thus, the IVF will offer increased sensitivity for SM measurements (e.g. angular correlations), but also for the search of BSM physics (e.g. final states with boosted Higgs bosons decaying into b-quarks). For the first time, the dependence of the IVF reconstruction efficiency on the distance of vertices in the η-φ plane is investigated with a data-driven approach. We use a clean set of top quark pair events, selected from data recorded in 2012 in pp-collisions at 8 TeV with the CMS detector, and perform a template fit to a 2D-distribution of the masses of the vertices in an event. Correction factors are derived for the application to simulated events. We conclude that our technique will enable precise calibration of double vertexing with the IVF in the LHC Run II.
DIRC - A particle identification system for BaBar
International Nuclear Information System (INIS)
The Detection of Internally Reflected Cherenkov light (DIRC) is a novel type of Cherenkov imaging device that has been developed, built and installed as part of the BaBar detector at the asymmetric B-factory PEP-II at SLAC. The DIRC is based on total internal reflection of Cherenkov photons produced and guided within thin, rectangular quartz bars covering the barrel region of BaBar. The photon detector is an array of photomultiplier tubes covering the photon phase space at the backward end of the bars. In its first few months of operation the DIRC performance has been found to achieve the design requirements. This note presents results from cosmic-ray data and an analysis of the first beam collision runs
DIRC - a particle identification system for BaBar
International Nuclear Information System (INIS)
The DIRC (an acronym for Detection of Internally Reflected Cherenkov light) is a novel type of Cherenkov imaging device that has been developed, built and installed as part of the BaBar detector at the asymmetric B-factory PEP-II at SLAC. The DIRC is based on total internal reflection of Cherenkov photons produced and guided within thin, rectangular quartz bars covering the barrel region of BaBar. The photon detector is an array of photomultiplier tubes covering the photon phase space at the backward end of the bars. In its first few months of operation the DIRC performance has been found to achieve the design requirements. This note presents results from cosmic ray data and an analysis of the first beam collision runs. (author)
Monitoring the BaBar Data Acquisition System
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The BaBar data acquisition system(DAQ)transports data from the detector front end eletronics to short term disk storage.A monitoring application(VMON)has been developed to monitor the one hundred and ninety computers in the dataflow system.Performance information for each CPU is collected and multicast across the existing data transport network.The packets are currently collected by a single UNIX workstation and archived.A ROOT based GUI provides control and displays the DAQ performance in real time.The same GUI is reused to recover archived VMON data,VMON has been deployed and constantly monitors the BaBar dataflow system.It has been used for diagnostics and provides input to models projecting future performance.The application has no measurable impact on data taking ,responds instantaneously on the human timescale to requests for information display,and uses only 3% of a 300MHz Sun Ultra5 CPU.
Searches for New Physics in CP Violation from BABAR
International Nuclear Information System (INIS)
Results of recent searches for new physics in CP violation in charm decays from the BABAR experiment are presented. These results include a measurement of D0 - anti D0 mixing and searches for CP violation in two-body D0 decays, a search for CP violation in the charm decays D± → KS0K± and DS± → KS0K± , KS0π± , and a search for direct CP violation in the singly-Cabibbo suppressed D± → K+K-π±decays. These studies are based on the final dataset collected by BABAR at the PEP-II B factory at SLAC in the period 1999-2008. No evidence of CP violation is found in these charm decays. The measured mixing parameter yCP = [0.72 ± 0.18(stat) ± 0.12(syst)]% excludes the no-mixing null hypothesis with a significance of 3.3σ.
Babar on the trail of anti-matter
International Nuclear Information System (INIS)
Since the discovery of anti-matter obviousness in Dirac's equations in 1928, the physicists have tried to explain the reasons of its rarity in the universe. The new Babar detector of the Stanford Linear Accelerator Center (SLAC) was built to test the standard model and to explore the CP violation. This digest paper gives a broad presentation of the standard model and of the fundamental interactions. It recalls the successive experiments carried out to detect some signatures of the CP violation and presents the SLAC installations and the Babar experiment started in 1993 for the study of Bd0 and B-bard0 meson disintegrations. Another experiment for the study of the CP violation, called Belle, started at the same time at the High Energy Accelerator Research Organisation (KEK) at Tsukuba (Japan). Both experiments should reach their goal until the end of the year 2000. (J.S.)
CLIQUE IRREDUCIBILITY AND CLIQUE VERTEX IRREDUCIBILITY OF GRAPHS
Directory of Open Access Journals (Sweden)
A. Vijayakumar
2009-02-01
Full Text Available A graphs G is clique irreducible if every clique in G of size at least two, has an edge which does not lie in any other clique of G and is clique reducible if it is not clique irreducible. A graph G is clique vertex irreducible if every clique in G has a vertex which does not lie in any other clique of G and clique vertex reducible if it is not clique vertex irreducible. The clique vertex irreducibility and clique irreducibility of graphs which are non-complete extended p-sums (NEPS of two graphs are studied. We prove that if Gc has at least two non-trivial components then G is clique vertex reducible and if it has at least three non-trivial components then G is clique reducible. The cographs and the distance hereditary graphs which are clique vertex irreducible and clique irreducible are also recursively characterized.
An $E_8$-approach to the moonshine vertex operator algebra
Shimakura, Hiroki
2010-01-01
In this article, we study the moonshine vertex operator algebra starting with the tensor product of three copies of the vertex operator algebra $V_{\\sqrt2E_8}^+$, and describe it by the quadratic space over $\\F_2$ associated to $V_{\\sqrt2E_8}^+$. Using quadratic spaces and orthogonal groups, we show the transitivity of the automorphism group of the moonshine vertex operator algebra on the set of all full vertex operator subalgebras isomorphic to the tensor product of three copies of $V_{\\sqrt2E_8}^+$, and determine the stabilizer of such a vertex operator subalgebra. Our approach is a vertex operator algebra analogue of "An $E_8$-approach to the Leech lattice and the Conway group" by Lepowsky and Meurman. Moreover, we find new analogies among the moonshine vertex operator algebra, the Leech lattice and the extended binary Golay code.
The BaBar Electromagnetic Calorimeter: Status and Performance Improvements
Bauer, Johannes M.; Group, for the BaBar Collaboration EMC
2006-01-01
The electromagnetic calorimeter at the BaBar detector, part of the asymmetric B Factory at SLAC, measures photons in the energy range from 20 MeV to 8 GeV with high resolution. The current status of the calorimeter, now in its seventh year of operation, is being presented, as well as details on improvements made to the analysis code during the last years.
The BaBar detector: Upgrades, operation and performance
Aubert, B.; Barate, R.; Boutigny, D; Couderc, F.; del Amo Sanchez, P; Gaillard, JM; Hicheur, A.; Karyotakis, Y.; Lees, JP; Poireau, V.; X. Prudent; Robbe, P.; Tisserand, V.; Zghiche, A.; Grauges, E.
2013-01-01
The BaBar detector operated successfully at the PEP-II asymmetric e +e- collider at the SLAC National Accelerator Laboratory from 1999 to 2008. This report covers upgrades, operation, and performance of the collider and the detector systems, as well as the trigger, online and offline computing, and aspects of event reconstruction since the beginning of data taking. © 2013 Elsevier B.V.
Particle identification using the DIRC in BaBar
International Nuclear Information System (INIS)
The BaBar DIRC runs extremely well at design luminosities, providing excellent PID in both ring and veto modes. Machine backgrounds expected as PEP-II goes to much higher luminosities (1034 cm2·s-1 or more) in the next 5 years will require faster data acquisition electronics and further shielding of the SOB from low energy machine produced gamma rays
Results from BABAR/PEP-II - one year of operations
International Nuclear Information System (INIS)
The performance of the BABAR Experiment at PEP-II (SLAC) as of June 2000 is presented. The PEP-II asymmetric e+e- collider has achieved record luminosities and has thus far delivered an exposure in excess of 12 fb-1. A large fraction of this data has been analysed to study the performance of the detector subsystems, and to prepare for the imminent production of first physics results
Electroweak Penguin and Leptonic Decays at BaBar
Energy Technology Data Exchange (ETDEWEB)
Bucci, F.; /Pisa U. /INFN, Pisa
2005-08-26
Recent BABAR results on electroweak penguin and leptonic decays are reviewed. In particular, the measurements of B {yields} K{sup (*)}l{sup +}l{sup -} and the preliminary results on B {yields} X{sub s}l{sup +}l{sup -} are presented. Also summarized are the preliminary limits on B{sup +} {yields} l{sup +}{nu} (l = e,{mu}) and B{sup +} {yields} K{sup +}{nu}{bar {nu}}.
Search for Low-Mass Dark Matter at BABAR
Echenard, B.
2012-01-01
This review briefly describes light dark matter searches performed by the BABAR experiment. Although dark matter candidates have traditionally been associated with heavy particles appearing in extensions of the Standard Model, a lighter component remains a well motivated alternative, and many scenarios of light dark matter have been recently proposed. Thanks to their large luminosities, B factories offer an ideal environment to probe these possibilities, complementing searches from direct det...
Quarkonium Spectroscopy and New States from BaBar
Energy Technology Data Exchange (ETDEWEB)
Vitale, L.; /Trieste U. /INFN, Trieste
2007-06-08
We review results on charmonium and bottomonium spectroscopy by the BaBar experiment at the PEP-II e{sup +}e{sup -} collider at SLAC. More space is reserved to the new results like the observation of hadronic non-B{bar B} {Upsilon}(4S) decays and the investigation on the production and decay properties of the recently discovered charmonium-like states X(3872) and Y (4260). These results are preliminary, unless otherwise specified.
The BaBar Software Architecture and Infrastructure
International Nuclear Information System (INIS)
The BaBar experiment has in place since 1995 a software release system (SRT Software Release Tools) based on CVS (Concurrent Version System) which is in common for all the software developed for the experiment, online or offline, simulation or reconstruction. A software release is a snapshot of all BaBar code (online, offline, utilities, scripts, makefiles, etc.). This set of code is tested to work together, and is indexed by a release number (e.g., 6.8.2) so a user can refer to a particular release and get reproducible results. A release will involve particular versions of packages. A package generally consists of a set of code for a particular task, together with a GNU makefile, scripts and documentation. All BaBar software is maintained in AFS (Andrew File System) directories, so the code is accessible worldwide within the Collaboration. The combination SRT, CVS, AFS, has demonstrated to be a valid, powerful and efficient way of organizing the software infrastructure of a modern HEP experiment with collaborating Institutes distributed worldwide, both in a development and production phase
The BaBar software architecture and infrastructure
International Nuclear Information System (INIS)
The BABAR experiment has in place since 1995 a software release system (SRT Software Release Tools) based on CVS (Concurrent Version System) which is in common for all the software developed for the experiment, online or offline, simulation or reconstruction. A software release is a snapshot of all BABAR code (online, offline, utilities, scripts, makefiles, etc.). This set of code is tested to work together, and is indexed by a release number (e.g., 6.8.2) so a user can refer to a particular release and get reproducible results. A release will involve particular versions of packages. A package generally consists of a set of code for a particular task, together with a GNUmakefile, scripts and documentation. All BABAR software is maintained in AFS (Andrew File System) directories, so the code is accessible worldwide within the Collaboration. The combination SRT, CVS, AFS, has demonstrated to be a valid, powerful and efficient way of organizing the software infrastructure of a modern HEP experiment with collaborating Institutes distributed worldwide, both in a development and production phase
Bimodules associated to vertex operator superalgebras
Institute of Scientific and Technical Information of China (English)
2008-01-01
Let V be a vertex operator superalgebra and m,n ∈ 21Z+. We construct an An(V ) -Am(V )-bimodule An,m(V ) which characterizes the action of V from the level m subspace to level n subspace of an admissible V -module. We also construct the Verma type admissible V -module from an Am(V )-module by using bimodules
The radical of a vertex operator algebra
Dong, C.; Li, H.; Mason, G.; Montague, P
1996-01-01
The radical $J(V)$ of a vertex operator algebra $V$ is defined to be the subspace of $V$ consisting of vectors $v$ such that the zero mode $o(v)=0$ on $V$ where $o(v)=v_{wt v-1}$ if $v$ is homogeneous. We establish various facts about $o(v),$ including the determination of $J(V)$ which is shown to be essentially equal to $(L(0)+L(-1))V.$
Dynamic Approximate Vertex Cover and Maximum Matching
Onak, Krzysztof; Rubinfeld, Ronitt
2010-01-01
We consider the problem of maintaining a large matching or a small vertex cover in a dynamically changing graph. Each update to the graph is either an edge deletion or an edge insertion. We give the first randomized data structure that simultaneously achieves a constant approximation factor and handles a sequence of k updates in k. polylog(n) time. Previous data structures require a polynomial amount of computation per update. The starting point of our construction is a distributed algorit...
Nonperturbative Aspects of Axial Vector Vertex
Institute of Scientific and Technical Information of China (English)
ZONG Hong-Shi; CHEN Xiang-Song; WANG Fan; CHANG Chao-Hsi; ZHAO En-Guang
2002-01-01
It is shown how the axial vector current of current quarks is related to that of constituent quarks within the framework of the global color symmetry model.Gluon dressing of the axial vector vertex and the quark self-energy functions are described by the inhomogeneous Bethe-Salpeter equation in the ladder approximation and the Schwinger Dyson equation in the rainbow approximation,respectively.
Spin wave Feynman diagram vertex computation package
Price, Alexander; Javernick, Philip; Datta, Trinanjan
Spin wave theory is a well-established theoretical technique that can correctly predict the physical behavior of ordered magnetic states. However, computing the effects of an interacting spin wave theory incorporating magnons involve a laborious by hand derivation of Feynman diagram vertices. The process is tedious and time consuming. Hence, to improve productivity and have another means to check the analytical calculations, we have devised a Feynman Diagram Vertex Computation package. In this talk, we will describe our research group's effort to implement a Mathematica based symbolic Feynman diagram vertex computation package that computes spin wave vertices. Utilizing the non-commutative algebra package NCAlgebra as an add-on to Mathematica, symbolic expressions for the Feynman diagram vertices of a Heisenberg quantum antiferromagnet are obtained. Our existing code reproduces the well-known expressions of a nearest neighbor square lattice Heisenberg model. We also discuss the case of a triangular lattice Heisenberg model where non collinear terms contribute to the vertex interactions.
Prototyping the CBM Micro Vertex Detector
International Nuclear Information System (INIS)
For the reconstruction of Open Charm Hadrons with the CBM experiment a Micro Vertex Detector (MVD) with an excellent resolution of the secondary decay vertex (< 70 μm along the beam axis) is required. To achieve this vertex resolution a material budget of a few 0.1% X0 is mandatory for the individual detector stations positioned downstream in close vicinity to the target. To further reduce the multiple scattering the MVD operates in vacuum. The need of prototyping and characterizing the CBM-MVD motivated the construction of an advanced device - a beam telescope - giving the opportunity to exercise the following aspects: handling and integration of ultra-thin CMOS sensors on advanced materials like CVD diamond, double sided sensor assembly for ultra-precise tracking, cooling, scalable readout and slow control, development of data analysis framework and first steps towards implementation of tracking algorithms into a FPGA-based hardware. This group report aims to summarize the activity towards fabrication of the CBM-MVD prototype.
Markov branching in the vertex splitting model
International Nuclear Information System (INIS)
We study a special case of the vertex splitting model which is a recent model of randomly growing trees. For any finite maximum vertex degree D, we find a one parameter model, with parameter α element of [0,1] which has a so-called Markov branching property. When D=∞ we find a two parameter model with an additional parameter γ element of [0,1] which also has this feature. In the case D = 3, the model bears resemblance to Ford's α-model of phylogenetic trees and when D=∞ it is similar to its generalization, the αγ-model. For α = 0, the model reduces to the well known model of preferential attachment. In the case α > 0, we prove convergence of the finite volume probability measures, generated by the growth rules, to a measure on infinite trees which is concentrated on the set of trees with a single spine. We show that the annealed Hausdorff dimension with respect to the infinite volume measure is 1/α. When γ = 0 the model reduces to a model of growing caterpillar graphs in which case we prove that the Hausdorff dimension is almost surely 1/α and that the spectral dimension is almost surely 2/(1 + α). We comment briefly on the distribution of vertex degrees and correlations between degrees of neighbouring vertices
The vertex-face correspondence and correlation functions of the fusion eight-vertex model
Energy Technology Data Exchange (ETDEWEB)
Kojima, Takeo [Department of Mathematics, College of Science and Technology, Nihon University, Chiyoda-ku, Tokyo 101-0062 (Japan)]. E-mail: kojima@math.cst.nihon-u.ac.jp; Konno, Hitoshi [Department of Mathematics, Faculty of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521 (Japan)]. E-mail: konno@mis.hiroshima-u.ac.jp; Weston, Robert [Department of Mathematics, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)]. E-mail: r.a.weston@ma.hw.ac.uk
2005-08-08
By making use of the vertex-face correspondence, we give an algebraic analysis formulation of correlation functions of the kxk fusion eight-vertex model in terms of the corresponding fusion SOS model. Here k-bar Z{sub >0}. A general formula for correlation functions is derived as a trace over the space of states of lattice operators such as the corner-transfer matrices, the half-transfer matrices (vertex operators) and the tail operator. We give a realization of these lattice operators as well as the space of states as objects in the level k representation theory of the elliptic algebra U{sub q,p}(sl{sub 2}-circumflex)
International Nuclear Information System (INIS)
High precision vertex detectors can be used to identify the decay products of parent particles which have lifetimes of the order 10-13 seconds. The paper summarises the performance achieved by a variety of techniques, and proceeds to a detailed discussion of the current status and potential of silicon detectors for high precision tracking. (author)
Kiani, Farooq A.; Hofmann, Matthias
2005-01-01
Density functional theory computations were carried out for 11-vertex nido-p-block-hetero(carba)boranes and -borates containing silicon, germanium, tin, arsenic, antimony, sulfur, selenium and tellurium heteroatoms. A set of quantitative values called “estimated energy penalties” was derived by comparing the energies of two reference structures that differ with respect to one structural feature only. These energy penalties behave additively, i.e., they allow us to reproduce the DFT-computed r...
The upgrade of the LHCb Vertex Locator (VELO)
van Beuzekom, M
2014-01-01
The upgrade of the LHCb experiment, planned for 2018, will enable the detector to run at a luminosity of 2 x 10$^{33}$ cm$^{-22}$s$^{-1}$ and explore New Physics effects in the beauty and charm sector with unprecedented precision. To achieve this, the entire readout will be transformed into a triggerless system operating at 40 MHz, where the event selection algorithms will be executed by high-level software in the CPU farm. The upgraded silicon vertex detector (VELO) must be lightweight, radiation hard, vacuum compatible, and has to drive data to the data acquisition system at speeds of up to 3 Tbit/s. This challenge will be met with a new VELO design based on hybrid pixel detectors, positioned to within 5 mm of the LHC colliding beams. The sensors have 55 x 55 $\\mu$m$^2$ square pixels and the VeloPix ASIC, which is being developed for the readout, is based on the Timepix/Medipix family of chips. The hottest ASIC will have to cope with integrated hit rates of up to 900 MHz which translates to a bandwidth of m...
Affine Vertex Operator Algebras and Modular Linear Differential Equations
Arike, Yusuke; Kaneko, Masanobu; Nagatomo, Kiyokazu; Sakai, Yuichi
2016-05-01
In this paper, we list all affine vertex operator algebras of positive integral levels whose dimensions of spaces of characters are at most 5 and show that a basis of the space of characters of each affine vertex operator algebra in the list gives a fundamental system of solutions of a modular linear differential equation. Further, we determine the dimensions of the spaces of characters of affine vertex operator algebras whose numbers of inequivalent simple modules are not exceeding 20.
Time-based vertex reconstruction in the Compact Muon Solenoid
Bartlett, Benjamin C.; Gray, Lindsey; Bornheim, Adolf; Spiropulu, María
2015-01-01
The Phase-II upgrades to the Large Hadron Collider will introduce a variety of new measurement devices to the CMS, including the High-Granularity Calorimeter (HGCAL). The increase in luminosity from these upgrades will also have the undesired side effect of vastly increasing pileup to a level at which the current machine learning vertex reconstruction (vertexing) algorithms cease to be effective. This will necessitate the development of further vertexing algorithms. Using high precision timin...
Affine Vertex Operator Algebras and Modular Linear Differential Equations
Arike, Yusuke; Kaneko, Masanobu; Nagatomo, Kiyokazu; Sakai, Yuichi
2016-04-01
In this paper, we list all affine vertex operator algebras of positive integral levels whose dimensions of spaces of characters are at most 5 and show that a basis of the space of characters of each affine vertex operator algebra in the list gives a fundamental system of solutions of a modular linear differential equation. Further, we determine the dimensions of the spaces of characters of affine vertex operator algebras whose numbers of inequivalent simple modules are not exceeding 20.
Searches for low-mass Higgs and dark bosons at BaBar
Energy Technology Data Exchange (ETDEWEB)
Oberhof, Benjamin, E-mail: benjamin.oberhof@pi.infn.it [INFN sezione di Pisa and Universitá di Pisa, Polo Fibonacci - Edificio C, Largo B. Pontecorvo 3, 56125 - Pisa (Italy)
2013-01-15
We present BaBar latest results for the direct search of a light CP-odd Higgs boson using radiative decays of the ϒ(nS) (n=1,2,3) resonances in different final states. We also present the results for the search of a hidden sector gauge and Higgs bosons using the full BaBar datasample.
Semileptonic $B_s$ decays at Belle, Babar, and D0
Urquijo, Phillip
2013-01-01
Studies of semileptonic $B_s$ decays by the Belle, Babar and D0 experiments are reported. In particular measurements of inclusive semileptonic $B_s$ decays by Belle and Babar and the exclusive excited charm mode $B_s \\to D_{s1} \\mu \
On some families of arbitrarily vertex decomposable spiders
Directory of Open Access Journals (Sweden)
Tomasz Juszczyk
2010-01-01
Full Text Available A graph \\(G\\ of order \\(n\\ is called arbitrarily vertex decomposable if for each sequence \\((n_1, ..., n_k\\ of positive integers such that \\(\\sum _{i=1}^{k} n_i = n\\, there exists a partition \\((V_1, ..., V_k\\ of the vertex set of \\(G\\ such that for every \\(i \\in \\{1, ...., k\\}\\ the set \\(V_i\\ induces a connected subgraph of \\(G\\ on \\(n_i\\ vertices. A spider is a tree with one vertex of degree at least \\(3\\. We characterize two families of arbitrarily vertex decomposable spiders which are homeomorphic to stars with at most four hanging edges.
On fixed-parameter algorithms for Split Vertex Deletion
CYGAN, Marek; Pilipczuk, Marcin
2012-01-01
In the Split Vertex Deletion problem, given a graph G and an integer k, we ask whether one can delete k vertices from the graph G to obtain a split graph (i.e., a graph, whose vertex set can be partitioned into two sets: one inducing a clique and the second one inducing an independent set). In this paper we study fixed-parameter algorithms for Split Vertex Deletion parameterized by k: we show that, up to a factor quasipolynomial in k and polynomial in n, the Split Vertex Deletion problem can ...
Propagation of the trip behavior in the VENUS vertex chamber
International Nuclear Information System (INIS)
The high voltage system of the VENUS vertex chamber occasionally trips by a discharge somewhere among cathode electrodes during data taking. This trip behavior induces often additional trips at other electrodes such as the skin and the grid electrodes in the vertex chamber. This propagation mechanism of trips is so complicated in this system related with multi-electrodes. Although the vertex chamber is already installed inside the VENUS detector and consequently the discharge is not able to observe directly, a trial to estimate the propagation has been done using only the information which appears around the trip circuits and the power supply of the vertex chamber. (author)
Framed vertex operator algebras, codes and the moonshine module
Dong, C; Hoehn, G
1997-01-01
For a simple vertex operator algebra whose Virasoro element is a sum of commutative Virasoro elements of central charge 1/2, two codes are introduced and studied. It is proved that such vertex operator algebras are rational. For lattice vertex operator algebras and related ones, decompositions into direct sums of irreducible modules for the product of the Virasoro algebras of central charge 1/2 are explicitly described. As an application, the decomposition of the moonshine vertex operator algebra is obtained for a distinguished system of 48 Virasoro algebras.
LQG vertex with finite Immirzi parameter
Engle, Jonathan; Livine, Etera; Pereira, Roberto; Rovelli, Carlo
2007-01-01
We extend the definition of the "flipped" loop-quantum-gravity vertex to the case of a finite Immirzi parameter. We cover the Euclidean as well as the Lorentzian case. We show that the resulting dynamics is defined on a Hilbert space isomorphic to the one of loop quantum gravity, and that the area operator has the same discrete spectrum as in loop quantum gravity. This includes the correct dependence on the Immirzi parameter, and, remarkably, holds in the Lorentzian case as well. The ad hoc f...
Quantum affine symmetry in vertex models
Idzumi, M; Jimbo, M; Miwa, T; Nakashima, T; Tokihiro, T; Idzumi, Makoto; Iohara, Kenji; Jimbo, Michio; Miwa, Tetsuji; Nakashima, Toshiki; Tokihiro, Tetsuji
1993-01-01
We study the higher spin anologs of the six vertex model on the basis of its symmetry under the quantum affine algebra $U_q(\\slth)$. Using the method developed recently for the XXZ spin chain, we formulate the space of states, transfer matrix, vacuum, creation/annihilation operators of particles, and local operators, purely in the language of representation theory. We find that, regardless of the level of the representation involved, the particles have spin $1/2$, and that the $n$-particle space has an RSOS-type structure rather than a simple tensor product of the $1$-particle space. This agrees with the picture proposed earlier by Reshetikhin.
The Mark II Vertex Drift Chamber
International Nuclear Information System (INIS)
We have completed constructing and begun operating the Mark II Drift Chamber Vertex Detector. The chamber, based on a modified jet cell design, achieves 30 μm spatial resolution and 2 gas mixtures. Special emphasis has been placed on controlling systematic errors including the use of novel construction techniques which permit accurate wire placement. Chamber performance has been studied with cosmic ray tracks collected with the chamber located both inside and outside the Mark II. Results on spatial resolution, average pulse shape, and some properties of CO2 mixtures are presented. 10 refs., 12 figs., 1 tab
Dynamical Vertex Approximation for Nanoscopic Systems
International Nuclear Information System (INIS)
Full text: We present model calculations for nanoscopic systems including Hubbard-like Coulomb repulsion and double exchange interactions with localized, classical spins. We compare the results of the recently introduced nanoscopic version of the dynamical vertex approximation at dynamical mean field level against exact diagonalization for a Benzene-like ring, where the latter is doable. This comparison allows us to investigate the reliability of the approximation. It shows that, already at the simplest approximation level (i.e. including only local correlations) the results are very accurate in a rather wide range of parameters. Since the computational effort is highly reduced, it is suitable for studying more complex systems. (author)
B to (rho/omega) gamma at BaBar
Energy Technology Data Exchange (ETDEWEB)
Koeneke, Karsten; /SLAC
2008-02-06
This document describes the measurements of the branching fractions and isospin violations of the radiative electroweak penguin decays B {yields} ({rho}/{omega}){gamma} at the asymmetric-energy e{sup +}e{sup -} PEP-II collider with the BABAR detector. Together with the previously measured branching fractions of the decays B {yields} K*{gamma} the ratio of CKM-matrix elements |V{sub td}/V{sub ts}| are extracted and the length of the far side of the unitarity triangle is determined.
Selected Topics on Hadronic B Decays From BaBar
International Nuclear Information System (INIS)
Recent measurements of branching fractions and decay-rate asymmetries in charmless hadronic B decays at the BaBar experiment are presented. The selected topics include Dalitz plot analyses of B → K+ π-π and signal searches in B → PP and PV, where isoscalar mesons are involved, and in B → b1P, P and V denote a pseudoscalar and vector meson, respectively. Several measurements in charmless hadronic B decays have indicated possible deviations from the theoretical predictions within the Standard Model. The measurements presented would contribute to searching for and resolving such puzzles.
Penguin and rare decays in BaBar
Energy Technology Data Exchange (ETDEWEB)
Akar, Simon [Univ. Denis, Paris (France)
2015-04-29
We present recent results from the BABAR Collaboration on radiative decays. These include searches for new physics via measurements of several observables such as the time- dependent CP asymmetry in B^{0} → K^{0}_{S}π^{–} π^{+}γ exclusive decays, as well as direct CP asymmetries and branching fractions in B → X_{s}γ and B → X_{s}ℓ^{+}ℓ^{–} inclusive decays.
Measurement of the Spin of the Omega^- Hyperon at BABAR
The BABAR Collaboration; Aubert, B.
2006-01-01
A measurement of the spin of the Omega^- hyperon produced through the exclusive process Xi_c^0 --> Omega^- K^+ is presented using a total integrated luminosity of 116 fb^-1 recorded with the BABAR detector at the e^+ e^- asymmetric-energy B-Factory at SLAC. Under the assumption that the Xi_c^0 has spin 1/2, the angular distribution of the Lambda from Omega^- --> Lambda K^- decay is inconsistent with all half-integer Omega^- spin values other than 3/2. Lower statistics data for the process Ome...
Managing the BaBar object oriented database
International Nuclear Information System (INIS)
The BaBar experiment stores its data in an Object Oriented federated database supplied by Objectivity/DB(tm). This database is currently 350TB in size and is expected to increase considerably as the experiment matures. Management of this database requires careful planning and specialized tools in order to make the data available to physicists in an efficient and timely manner. The authors discuss the operational issues and management tools that were developed during the previous run to deal with this vast quantity of data at SLAC
Search for a muonic dark force at BABAR
The BABAR Collaboration
2016-01-01
Many models of physics beyond the Standard Model predict the existence of new Abelian forces with new gauge bosons mediating interactions between "dark sectors" and the Standard Model. We report a search for a dark boson Z' coupling only to the second and third generations of leptons in the reaction e+e- -> mu+mu- Z', Z' -> mu+mu- using 514 fb-1 of data collected by the BABAR experiment. No significant signal is observed for Z' masses in the range 0.212 - 10 GeV. Limits on the coupling parame...
BABAR Web job submission with Globus Authentication and AFS Access
International Nuclear Information System (INIS)
We present two versions of a grid job submission system produced for the BaBar experiment. Both use globus job submission to process data spread across various sites, producing output which can be combined for analysis. The problems encountered with authorization and authentication, data location, job submission, and the input and output sandboxes are described, as are the solutions. The total system is still some way short of the aims of enterprises such as the EDG, but represent a significant step along the way
The Construction of Spin Foam Vertex Amplitudes
Directory of Open Access Journals (Sweden)
Eugenio Bianchi
2013-01-01
Full Text Available Spin foam vertex amplitudes are the key ingredient of spin foam models for quantum gravity. These fall into the realm of discretized path integral, and can be seen as generalized lattice gauge theories. They can be seen as an attempt at a 4-dimensional generalization of the Ponzano-Regge model for 3d quantum gravity. We motivate and review the construction of the vertex amplitudes of recent spin foam models, giving two different and complementary perspectives of this construction. The first proceeds by extracting geometric configurations from a topological theory of the BF type, and can be seen to be in the tradition of the work of Barrett, Crane, Freidel and Krasnov. The second keeps closer contact to the structure of Loop Quantum Gravity and tries to identify an appropriate set of constraints to define a Lorentz-invariant interaction of its quanta of space. This approach is in the tradition of the work of Smolin, Markopoulous, Engle, Pereira, Rovelli and Livine.
Vertex Sparsifiers and Abstract Rounding Algorithms
Charikar, Moses; Li, Shi; Moitra, Ankur
2010-01-01
The notion of vertex sparsification is introduced in \\cite{M}, where it was shown that for any graph $G = (V, E)$ and a subset of $k$ terminals $K \\subset V$, there is a polynomial time algorithm to construct a graph $H = (K, E_H)$ on just the terminal set so that simultaneously for all cuts $(A, K-A)$, the value of the minimum cut in $G$ separating $A$ from $K -A$ is approximately the same as the value of the corresponding cut in $H$. We give the first super-constant lower bounds for how well a cut-sparsifier $H$ can simultaneously approximate all minimum cuts in $G$. We prove a lower bound of $\\Omega(\\log^{1/4} k)$ -- this is polynomially-related to the known upper bound of $O(\\log k/\\log \\log k)$. This is an exponential improvement on the $\\Omega(\\log \\log k)$ bound given in \\cite{LM} which in fact was for a stronger vertex sparsification guarantee, and did not apply to cut sparsifiers. Despite this negative result, we show that for many natural problems, we do not need to incur a multiplicative penalty fo...
Searches for New Physics in CP Violation from BABAR
Energy Technology Data Exchange (ETDEWEB)
Palombo, Fernando [Universita di Milano, Dipartimento di Fisica, Milano (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Milano (Italy). et al.
2015-05-12
Results of recent searches for new physics in CP violation in charm decays from the BABAR experiment are presented. These results include a measurement of D^{0} - anti D^{0} mixing and searches for CP violation in two-body D^{0} decays, a search for CP violation in the charm decays D^{±} → K_{S}^{0}K ^{±} and D_{ s}^{±} → K_{S}^{0}K^{±} , K_{S}^{0}π^{±} , and a search for direct CP violation in the singly-Cabibbo suppressed D^{±} → K^{+}K^{-}π^{±}decays. These studies are based on the final dataset collected by BABAR at the PEP-II B factory at SLAC in the period 1999-2008. No evidence of CP violation is found in these charm decays. The measured mixing parameter y_{CP} = [0.72 ± 0.18(stat) ± 0.12(syst)]% excludes the no-mixing null hypothesis with a significance of 3.3σ .
ILCRoot tracker and vertex detector response to MARS15 simulated backgrounds in muon collider
Energy Technology Data Exchange (ETDEWEB)
Terentiev, N.K.; /Carnegie Mellon U.; Di Benedetto, V.; /INFN, Lecce; Gatto, C.; /INFN, Naples; Mazzacane, A.; Mokhov, N.V.; Striganov, S.I.; /Fermilab
2011-10-01
Results from a simulation of the background for a muon collider, and the response of a silicon tracking detector to this background are presented. The background caused by decays of the 750-GeV muon beams was simulated using the MARS15 program, which included the infrastructure of the beam line elements near the detector and the 10{sup o} nozzles that shield the detector from this background. The ILCRoot framework, along with the Geant4 program, was used to simulate the response of the tracker and vertex silicon detectors to the muon-decay background remaining after the shielding nozzles. Results include the hit distributions in these detectors, the fractions of type-specific background particles producing these hits and illustrate the use of timing of the hits to suppress the muon beam background.
Subgraphs in vertex neighborhoods of K-free graphs
DEFF Research Database (Denmark)
Bang-Jensen, J.; Brandt, Stephan
2004-01-01
In a K-free graph, the neighborhood of every vertex induces a K-free subgraph. The K-free graphs with the converse property that every induced K-free subgraph is contained in the neighborhood of a vertex are characterized, based on the characterization in the case r = 3 due to Pach [8]. © 2004...
On the uniqueness of the moonshine vertex operator algebra
Dong, Chongying; Griess Jr., Robert L.; lam, Ching Hung
2005-01-01
It is proved that a vertex operator algebra is isomorphic to the moonshine VOA of Frenkel-Lepowsky-Meurman if it satisfies certain conditions. Our two main theorems establish a weak version of the FLM uniqueness conjecture for the moonshine vertex operator algebra. We believe that these are the first such results.
LHCb: Performance and Radiation Damage Effects in the LHCb Vertex Locator
Carvalho Akiba, K
2014-01-01
LHCb is a dedicated experiment to study New Physics in the decays of heavy hadrons at the LHC. Heavy hadrons are identified through their flight distance in the Vertex Locator (VELO), hence the detector is critical for both the trigger and offline physics analyses. The VELO is the retractable silicon-strip detector surrounding the LHCb interaction point. It is located only 7 mm from the LHC beam during normal LHC operation, once moved into its closed position for each LHC fill when stable beams are obtained. During insertion the detector is centred around the LHC beam by the online reconstruction of the primary vertex position. Both VELO halves comprise 21 silicon micro-strip modules each. A module is made of two n-on-n 300 $\\mu$m thick half-disc sensors with R-measuring and $\\phi$-measuring micro-strip geometry, mounted on a carbon fibre support paddle. The minimum pitch is approximately 40 $\\mu$m. The detector is also equipped with the only n-on-p sensors operating at the LHC. The detectors are operated in ...
Performance, Radiation Damage Effects and Upgrade of the LHCb Vertex Locator
De Capua, S
2013-01-01
LHCb is a dedicated experiment to study New Physics in the decays of heavy hadrons at the Large Hadron Collider (LHC). Heavy hadrons are identified through their flight distance in the VELO, the retractable silicon-strip vertex detector surrounding the LHCb interaction point at only 7 mm from the beam during normal LHC operation. Both VELO halves comprise 21 silicon micro-strip modules each. A module is made of two n-on-n 300 µm thick half-disc sensors with R- and phi-measuring geometry, mounted on a carbon fibre support paddle. The minimum pitch is approximately 40 µm. The detector is also equipped with the only n-on-p module operating at the LHC. The performance of the VELO in its three years of successful operation during the LHC physics runs will be presented. Highlights will include alignment, cluster finding efficiency, single hit resolution, and impact parameter and vertex resolutions. The VELO module sensors receive a large and non-uniform radiation dose having inner and outer radii of only 7 and 42...
C-Graded vertex algebras and conformal flow
International Nuclear Information System (INIS)
We consider C-graded vertex algebras, which are vertex algebras V with a C-grading such that V is an admissible V-module generated by “lowest weight vectors.” We show that such vertex algebras have a “good” representation theory in the sense that there is a Zhu algebra A(V) and a bijection between simple admissible V-modules and simple A(V)-modules. We also consider pseudo vertex operator algebras (PVOAs), which are C-graded vertex algebras with a conformal vector such that the homogeneous subspaces of V are generalized eigenspaces for L(0); essentially, these are VOAs that lack any semisimplicity or integrality assumptions on L(0). As a motivating example, we show that deformation of the conformal structure (conformal flow) of a strongly regular VOA (e.g., a lattice theory, or Wess-Zumino-Witten model) is a path in a space whose points are PVOAs
Twisted vertex algebras, bicharacter construction and boson-fermion correspondences
International Nuclear Information System (INIS)
The boson-fermion correspondences are an important phenomena on the intersection of several areas in mathematical physics: representation theory, vertex algebras and conformal field theory, integrable systems, number theory, cohomology. Two such correspondences are well known: the types A and B (and their super extensions). As a main result of this paper we present a new boson-fermion correspondence of type D-A. Further, we define a new concept of twisted vertex algebra of order N, which generalizes super vertex algebra. We develop the bicharacter construction which we use for constructing classes of examples of twisted vertex algebras, as well as for deriving formulas for the operator product expansions, analytic continuations, and normal ordered products. By using the underlying Hopf algebra structure we prove general bicharacter formulas for the vacuum expectation values for two important groups of examples. We show that the correspondences of types B, C, and D-A are isomorphisms of twisted vertex algebras
BaBar - A Community Web Site in an Organizational Setting
International Nuclear Information System (INIS)
The BABAR Web site was established in 1993 at the Stanford Linear Accelerator Center (SLAC) to support the BABAR experiment, to report its results, and to facilitate communication among its scientific and engineering collaborators, currently numbering about 600 individuals from 75 collaborating institutions in 10 countries. The BABAR Web site is, therefore, a community Web site. At the same time it is hosted at SLAC and funded by agencies that demand adherence to policies decided under different priorities. Additionally, the BABAR Web administrators deal with the problems that arise during the course of managing users, content, policies, standards, and changing technologies. Desired solutions to some of these problems may be incompatible with the overall administration of the SLAC Web sites and/or the SLAC policies and concerns. There are thus different perspectives of the same Web site and differing expectations in segments of the SLAC population which act as constraints and challenges in any review or re-engineering activities. Web Engineering, which post-dates the BABAR Web, has aimed to provide a comprehensive understanding of all aspects of Web development. This paper reports on the first part of a recent review of application of Web Engineering methods to the BABAR Web site, which has led to explicit user and information models of the BABAR community and how SLAC and the BABAR community relate and react to each other. The paper identifies the issues of a community Web site in a hierarchical, semi-governmental sector and formulates a strategy for periodic reviews of BABAR and similar sites. A separate paper reports on the findings of a user survey and selected interviews with users, along with their implications and recommendations for future
The Lorentzian proper vertex amplitude: Asymptotics
Engle, Jonathan; Zipfel, Antonia
2015-01-01
In previous work, the Lorentzian proper vertex amplitude for a spin-foam model of quantum gravity was derived. In the present work, the asymptotics of this amplitude are studied in the semi-classical limit. The starting point of the analysis is an expression for the amplitude as an action integral with action differing from that in the EPRL case by an extra `projector' term which scales linearly with spins only in the asymptotic limit. New tools are introduced to generalize stationary phase methods to this case. For the case of boundary data which can be glued to a non-degenerate Lorentzian 4-simplex, the asymptotic limit of the amplitude is shown to equal the single Feynman term, showing that the extra term in the asymptotics of the EPRL amplitude has been eliminated.
Evaluation of new spin foam vertex amplitudes
International Nuclear Information System (INIS)
The Christensen-Egan algorithm is extended and generalized to efficiently evaluate new spin foam vertex amplitudes proposed by Engle, Pereira and Rovelli and Freidel and Krasnov, with or without (factored) boundary states. A concrete pragmatic proposal is made for comparing the different models using uniform methodologies, applicable to the behavior of large spin asymptotics and of expectation values of specific semiclassical observables. The asymptotics of the new models exhibit non-oscillatory, power-law decay similar to that of the Barrett-Crane model, though with different exponents. Also, an analysis of the semiclassical wave packet propagation problem indicates that the Magliaro, Rovelli and Perini's conjecture of good semiclassical behavior of the new models does not hold for generic factored states, which neglect spin-spin correlations.
Vertex Nomination via Content and Context
Coppersmith, Glen A
2012-01-01
If I know of a few persons of interest, how can a combination of human language technology and graph theory help me find other people similarly interesting? If I know of a few people committing a crime, how can I determine their co-conspirators? Given a set of actors deemed interesting, we seek other actors who are similarly interesting. We use a collection of communications encoded as an attributed graph, where vertices represents actors and edges connect pairs of actors that communicate. Attached to each edge is the set of documents wherein that pair of actors communicate, providing content in context - the communication topic in the context of who communicates with whom. In these documents, our identified interesting actors communicate amongst each other and with other actors whose interestingness is unknown. Our objective is to nominate the most likely interesting vertex from all vertices with unknown interestingness. As an illustrative example, the Enron email corpus consists of communications between ac...
The CDF vertex time projection chamber system
International Nuclear Information System (INIS)
The vertex time projection chamber (VTPC) system is one of the major components of the charged particle tracking system for the Collider Detector at Fermilab (CDF). The chambers cover about seven units of pseudorapidity (η) and must be capable of handling substantially more than the 30-35 charged particle tracks produced by typical anti pp collisions at center-of-mass energies of 1.8 TeV. The chambers are optimized to provide the good pattern recognition in the r-z view required to locate the event vertex, measure the overall event topology, and to complement the r-φ tracking in the large axial wire drift chamber that surrounds them. The chambers provide r-z information using TDC data from sense wire signals. Information on the φ of tracks is obtained from cathode pad signals on a subset of chambers read out by a FADC system. A similar system measures dE/dx of tracks in the forward cones surrounding the exiting beams. Because of the large number of photons that pass through the detector during each collision, novel techniques are required to reduce the amount of material in the chamber. These techniques include a custom surface mount integrated circuit preamplifier, epoxy-graphite and Kapton covered foam structural members, and miniature coaxial signal cables. The mechanical construction of the chamber, radiation length vs angle, and details of the electronics are described. The event reconstruction, corrections, and preliminary performance results for 1.8 TeV anti pp collisions are also discussed. (orig.)
Monte-Carlo Analysis of the Flavour Changing Neutral Current B \\to Gamma at Babar
Energy Technology Data Exchange (ETDEWEB)
Smith, D. [Imperial College, London (United Kingdom)
2001-09-01
The main theme of this thesis is a Monte-Carlo analysis of the rare Flavour Changing Neutral Current (FCNC) decay b→sγ. The analysis develops techniques that could be applied to real data, to discriminate between signal and background events in order to make a measurement of the branching ratio of this rare decay using the BaBar detector. Also included in this thesis is a description of the BaBar detector and the work I have undertaken in the development of the electronic data acquisition system for the Electromagnetic calorimeter (EMC), a subsystem of the BaBar detector.
Searches for CP violation in charm decays at BABAR
Neri, Nicola
2013-01-01
In the Standard Model \\CP violation in charm decays is expected to be very small, at the level of 0.1% or less. A significant excess of \\CP violation with respect to the Standard Model predictions would be a signature of new physics. We report on recent searches for \\CP violation in charm meson decays at \\babar, using a data sample corresponding to an integrated luminosity of about 470 \\invfb. In particular, we report on searches for \\CPV in the 3-body $\\Dp\\to\\Kp\\Km\\pip$ decay and for decay modes with a \\KS in the final state, such as $\\Dp\\to\\KS\\Kp$, $\\Ds\\to\\KS\\Kp$, $\\Ds\\to\\KS\\pip$. A lifetime ratio analysis of $\\Dz\\to\\Kp\\Km, \\pip\\pim$ with respect to $\\Dz\\to\\Km\\pip$ decays, which is sensitive to \\Dz-\\Dzb mixing and \\CP violation, is also presented here.
The BaBar superconducting coil: design, construction and test
International Nuclear Information System (INIS)
The BABAR Detector, located in the PEP-II B-Factory at the Stanford Linear Accelerator Center, includes a large 1.5 Tesla superconducting solenoid, 2.8 m bore and length 3.7 m. The two layer solenoid is wound with an aluminum stabilized conductor which is graded axially to produce a +/- 3% field uniformity in the tracking region. This paper summarizes the 3 year design, fabrication and testing program of the superconducting solenoid. The work was carried out by an international collaboration between INFN, LLNL and SLAC. The coil was constructed by Ansaldo Energia. Critical current measurements of the superconducting strand, cable and conductor, cool-down, operation with the thermo-siphon cooling, fast and slow discharges, and magnetic forces are discussed in detail
The Babar experiment: computing issues for the year 2000
International Nuclear Information System (INIS)
The BaBar experiment at the PEP-II asymmetric e+e- Collider at SLAC is due to commence data taking early in 1999. This talk will briefly describe the detector and its physics goals in order to set the scale of the computing problem. Approximately 109 events, corresponding to 80 TBytes of information, are expected to be accumulated per year. In addition the collaboration is large and geophisically dispersed - almost 500 physicists from 80 institutions in 10 countries. Thus the computing issues break down into two categories - technical and sociological/managerial. Both of these will be discussed. The major focus will be on the work that is underway to establish a distributed software development environment, the computing model that is the baseline plan for dealing with the onslaught of data, and more speculative avenues that are expected to be explored in parallel with this baseline. (author)
Selected Topics in Tau Physics from BaBar
Energy Technology Data Exchange (ETDEWEB)
Paramesvaran, S.; /Royal Holloway, U. of London
2012-04-06
Selected results from {tau} analyses performed using the BABAR detector at the SLAC National Accelerator Laboratory are presented. A precise measurement of the {tau} mass and the {tau}{sup +}{tau}{sup -} mass difference is undertaken using the hadronic decay mode {tau}{sup {+-}} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup {+-}}{nu}{sub {tau}}. In addition an investigation into the strange decay modes {tau}{sup -} {yields} K{sub S}{sup 0}{pi}{sup -}{pi}{sup 0}{nu}{sub {tau}} and {tau}{sup -} {yields} K{sub S}{sup 0}{pi}{sup -}{nu}{sub {tau}} is also presented, including a fit to the {tau}{sup -} {yields} K{sub S}{sup 0}{pi}{sup -}{nu}{sub {tau}} invariant mass spectrum. Precise values for M(K*(892)) and {Lambda}(K*(892)) are obtained.
Recent Results on T and CP Violation at BABAR
Energy Technology Data Exchange (ETDEWEB)
Perez Perez, Alejandro [Istituto Nazionale di Fisica Nucleare (INFN), Pisa (Italy).
2015-02-06
CP-violation (CPV) and Time-reversal violation (TRV) are intimately related through the CPT theorem: if one of these discrete symmetries is violated the other one has to be violated in such a way to conserve CPT. Although CPV in the B^{0}B^{0}-bar system has been established by the B-factories, implying indirectly TRV, there is still no direct evidence of TRV. We report on the observation of TRV in the B-meson system performed with a dataset of 468 × 10^{6} BB-bar pairs produced in Υ(4S) decays collected by the BABAR detector at the PEP-II asymmetric-energy e^{+}e^{-} collider at the SLAC National Accelerator Laboratory. We also report on other CPV measurements recently performed on the B-meson system
Recent Results on T and CP Violation at BABAR
International Nuclear Information System (INIS)
CP-violation (CPV) and Time-reversal violation (TRV) are intimately related through the CPT theorem: if one of these discrete symmetries is violated the other one has to be violated in such a way to conserve CPT. Although CPV in the B0B0-bar system has been established by the B-factories, implying indirectly TRV, there is still no direct evidence of TRV. We report on the observation of TRV in the B-meson system performed with a dataset of 468 x 106 BB-bar pairs produced in Y(4S) decays collected by the BABAR detector at the PEP-II asymmetric-energy e+e- collider at the SLAC National Accelerator Laboratory. We also report on other CPV measurements recently performed on the B-meson system
The BaBar Experiment's Distributed Computing Model
International Nuclear Information System (INIS)
In order to face the expected increase in statistics between now and 2005, the BaBar experiment at SLAC is evolving its computing model toward a distributed multi-tier system. It is foreseen that data will be spread among Tier-A centers and deleted from the SLAC center. A uniform computing environment is being deployed in the centers, the network bandwidth is continuously increased and data distribution tools has been designed in order to reach a transfer rate of ∼100 TB of data per year. In parallel, smaller Tier-B and C sites receive subsets of data, presently in Kanga-ROOT[1] format and later in Objectivity[2] format. GRID tools will be used for remote job submission
The BaBar experiment's distributed computing model
International Nuclear Information System (INIS)
In order to face the expected increase in statistics between now and 2005, the BaBar experiment at SLAC is evolving its computing model toward a distributed multitier system. It is foreseen that data will be spread among Tier-A centers and deleted from the SLAC center. A uniform computing environment is being deployed in the centers, the network bandwidth is continuously increased and data distribution tools has been designed in order to reach a transfer rate of ∼100 TB of data per year. In parallel, smaller Tier-B and C sites receive subsets of data, presently in Kanga-ROOT format and later in Objectivity format. GRID tools will be used for remote job submission
Search for a muonic dark force at BABAR
,
2016-01-01
Many models of physics beyond the Standard Model predict the existence of new Abelian forces with new gauge bosons mediating interactions between "dark sectors" and the Standard Model. We report a search for a dark boson Z' coupling only to the second and third generations of leptons in the reaction e+e- -> mu+mu- Z', Z' -> mu+mu- using 514 fb-1 of data collected by the BABAR experiment. No significant signal is observed for Z' masses in the range 0.212 - 10 GeV. Limits on the coupling parameter g' as low as 7x10^-4 are derived, leading to improvements in the bounds compared to those previously derived from neutrino experiments.
The MAPS based PXL vertex detector for the STAR experiment
Contin, G.; Anderssen, E.; Greiner, L.; Schambach, J.; Silber, J.; Stezelberger, T.; Sun, X.; Szelezniak, M.; Vu, C.; Wieman, H.; Woodmansee, S.
2015-03-01
The Heavy Flavor Tracker (HFT) was installed in the STAR experiment for the 2014 heavy ion run of RHIC. Designed to improve the vertex resolution and extend the measurement capabilities in the heavy flavor domain, the HFT is composed of three different silicon detectors based on CMOS monolithic active pixels (MAPS), pads and strips respectively, arranged in four concentric cylinders close to the STAR interaction point. The two innermost HFT layers are placed at a radius of 2.7 and 8 cm from the beam line, respectively, and accommodate 400 ultra-thin (50 μ m) high resolution MAPS sensors arranged in 10-sensor ladders to cover a total silicon area of 0.16 m2. Each sensor includes a pixel array of 928 rows and 960 columns with a 20.7 μ m pixel pitch, providing a sensitive area of ~ 3.8 cm2. The architecture is based on a column parallel readout with amplification and correlated double sampling inside each pixel. Each column is terminated with a high precision discriminator, is read out in a rolling shutter mode and the output is processed through an integrated zero suppression logic. The results are stored in two SRAM with ping-pong arrangement for a continuous readout. The sensor features 185.6 μ s readout time and 170 mW/cm2 power dissipation. The detector is air-cooled, allowing a global material budget as low as 0.39% on the inner layer. A novel mechanical approach to detector insertion enables effective installation and integration of the pixel layers within an 8 hour shift during the on-going STAR run.In addition to a detailed description of the detector characteristics, the experience of the first months of data taking will be presented in this paper, with a particular focus on sensor threshold calibration, latch-up protection procedures and general system operations aimed at stabilizing the running conditions. Issues faced during the 2014 run will be discussed together with the implemented solutions. A preliminary analysis of the detector performance
The MAPS based PXL vertex detector for the STAR experiment
International Nuclear Information System (INIS)
The Heavy Flavor Tracker (HFT) was installed in the STAR experiment for the 2014 heavy ion run of RHIC. Designed to improve the vertex resolution and extend the measurement capabilities in the heavy flavor domain, the HFT is composed of three different silicon detectors based on CMOS monolithic active pixels (MAPS), pads and strips respectively, arranged in four concentric cylinders close to the STAR interaction point. The two innermost HFT layers are placed at a radius of 2.7 and 8 cm from the beam line, respectively, and accommodate 400 ultra-thin (50 μ m) high resolution MAPS sensors arranged in 10-sensor ladders to cover a total silicon area of 0.16 m2. Each sensor includes a pixel array of 928 rows and 960 columns with a 20.7 μ m pixel pitch, providing a sensitive area of ∼ 3.8 cm2. The architecture is based on a column parallel readout with amplification and correlated double sampling inside each pixel. Each column is terminated with a high precision discriminator, is read out in a rolling shutter mode and the output is processed through an integrated zero suppression logic. The results are stored in two SRAM with ping-pong arrangement for a continuous readout. The sensor features 185.6 μ s readout time and 170 mW/cm2 power dissipation. The detector is air-cooled, allowing a global material budget as low as 0.39% on the inner layer. A novel mechanical approach to detector insertion enables effective installation and integration of the pixel layers within an 8 hour shift during the on-going STAR run.In addition to a detailed description of the detector characteristics, the experience of the first months of data taking will be presented in this paper, with a particular focus on sensor threshold calibration, latch-up protection procedures and general system operations aimed at stabilizing the running conditions. Issues faced during the 2014 run will be discussed together with the implemented solutions. A preliminary analysis of the detector
Algorithmic tools for simulations of vertex models on random graphs
International Nuclear Information System (INIS)
We consider the coupling of ice-type vertex models to random, planar phi4 quantum-gravity graphs. The well-established techniques for the simulation of dynamical triangulations and their dual phi3 graphs are suitably adapted to the case of four-valent graphs. These methods are combined with a formulation of the loop algorithm for the simulation of the vertex model matter part. We present a preliminary analysis of the dynamical scaling behaviour of the combined algorithm for the case of the 6-vertex model coupled to quantum gravity
The 8-vertex model with quasi-periodic boundary conditions
Niccoli, G.; Terras, V.
2015-01-01
We study the inhomogeneous 8-vertex model (or equivalently the XYZ Heisenberg spin-1/2 chain) with all kinds of integrable quasi-periodic boundary conditions: periodic, $\\sigma^x$-twisted, $\\sigma^y$-twisted or $\\sigma^z$-twisted. We show that in all these cases but the periodic one with an even number of sites $\\mathsf{N}$, the transfer matrix of the model is related, by the vertex-IRF transformation, to the transfer matrix of the dynamical 6-vertex model with antiperiodic boundary condition...
Measurement of $R_{b}$ using a Vertex Mass Tag
Abe, K; Akagi, T; Allen, N J; Ash, W W; Aston, D; Baird, K G; Baltay, C; Band, H R; Barakat, M B; Baranko, G; Bardon, O; Barklow, T L; Bashindzhagian, G L; Bazarko, A O; Ben-David, R; Benvenuti, Alberto C; Bilei, G M; Bisello, D; Blaylock, G; Bogart, J R; Bolen, B; Bolton, T; Bower, G R; Brau, J E; Breidenbach, M; Bugg, W M; Burke, D; Burnett, T H; Burrows, P N; Busza, W; Calcaterra, A; Caldwell, D O; Calloway, D; Camanzi, B; Carpinelli, M; Cassell, R; Castaldi, R; Castro, A; Cavalli-Sforza, M; Chou, A; Church, E; Cohn, H O; Coller, J A; Cook, V; Cotton, R; Cowan, R F; Coyne, D G; Crawford, G; de Oliveira, A; Damerell, C J S; Daoudi, M; De Groot, N; De Sangro, R; Dell'Orso, R; Dervan, P J; Dima, M; Dong, D N; Du, P Y C; Dubois, R; Eisenstein, B I; Elia, R; Etzion, E; Fahey, S; Falciai, D; Fan, C; Fernández, J P; Fero, M J; Frey, R; Gillman, T; Gladding, G; González, S; Hart, E L; Harton, J L; Hasan, A; Hasegawa, Y; Hasuko, K; Hedges, S J; Hertzbach, S S; Hildreth, M D; Huber, J; Huffer, M E; Hughes, E W; Hwang, H; Iwasaki, Y; Jackson, D J; Jacques, P; Jaros, J A; Jiang, Z Y; Johnson, A S; Johnson, J R; Johnson, R A; Junk, T R; Kajikawa, R; Kalelkar, M; Kang, H J; Karliner, I; Kawahara, H; Kendall, H W; Kim, Y D; King, M E; King, R; Kofler, R R; Krishna, N M; Kroeger, R S; Labs, J F; Langston, M; Lath, A; Lauber, J A; Leith, D W G S; Lia, V; Liu, M X; Liu, X; Loreti, M; Lu, A; Lynch, H L; Ma, J; Mancinelli, G; Manly, S; Mantovani, G C; Markiewicz, T W; Maruyama, T; Masuda, H; Mazzucato, E; McKemey, A K; Meadows, B T; Messner, R; Mockett, P M; Moffeit, K C; Moore, T B; Müller, D; Nagamine, T; Narita, S; Nauenberg, U; Neal, H; Nussbaum, M; Ohnishi, Y; Oishi, N; Onoprienko, D; Osborne, L S; Panvini, R S; Park, C H; Park, H; Pavel, T J; Peruzzi, I; Piccolo, M; Piemontese, L; Pieroni, E; Pitts, K T; Plano, R J; Prepost, R; Prescott, C Y; Punkar, G D; Quigley, J; Ratcliff, B N; Reeves, T W; Reidy, J; Reinertsen, P L; Rensing, P E; Rochester, L S; Rowson, P C; Russell, J J; Saxton, O H; Schalk, T; Schindler, R H; Schumm, B A; Schwiening, J; Sen, S; Serbo, V V; Shaevitz, M H; Shank, J T; Shapiro, G; Sherden, D J; Shmakov, K D; Simopoulos, C; Sinev, N B; Smith, S R; Smy, M B; Snyder, J A; Stängle, H; Stamer, P; Steiner, H; Steiner, R; Strauss, M G; Su, D; Suekane, F; Sugiyama, A; Suzuki, S; Swartz, M; Szumilo, A; Takahashi, T; Taylor, F E; Torrence, E; Trandafir, A I; Turk, J D; Usher, T; Vavra, J; Vannini, C; Vella, E; Venuti, J P; Verdier, R; Verdini, P G; Wagner, D L; Wagner, S R; Waite, A P; Watts, S J; Weidemann, A W; Weiss, E R; Whitaker, J S; White, S L; Wickens, F J; Williams, D C; Williams, S H; Willocq, S; Wilson, R J; Wisniewski, W J; Woods, M; Word, G B; Wyss, J; Yamamoto, R K; Yamartino, J M; Yang, X; Yashima, J; Yellin, S J; Young, C C; Yuta, H; Zapalac, G; Zdarko, R W; Zhou, J
1998-01-01
We report a new measurement of Rb = Gamma(Z0->b-bbar) / Gamma(Z0->hadrons) using a double tag technique, where the b hemisphere selection is based on the reconstructed mass of the B hadron decay vertex. The measurement was performed using a sample of 130k hadronic Z0 events, collected with the SLD at the SLC. The method utilizes the 3-D vertexing abilities of the CCD pixel vertex detector and the small stable SLC beams to obtain a high b-tagging efficiency and purity. We obtain Rb=0.2142+/-0.0034(stat.)+/-0.0015(syst.)+/-0.0002(R_c).
On Vertex Covering Transversal Domination Number of Regular Graphs
Vasanthi, R.; Subramanian, K.
2016-01-01
A simple graph G = (V, E) is said to be r-regular if each vertex of G is of degree r. The vertex covering transversal domination number γvct(G) is the minimum cardinality among all vertex covering transversal dominating sets of G. In this paper, we analyse this parameter on different kinds of regular graphs especially for Qn and H3,n. Also we provide an upper bound for γvct of a connected cubic graph of order n ≥ 8. Then we try to provide a more stronger relationship between γ and γvct.
A MAPS Based Micro-Vertex Detector for the STAR Experiment
Schambach, Joachim; Anderssen, Eric; Contin, Giacomo; Greiner, Leo; Silber, Joe; Stezelberger, Thorsten; Sun, Xiangming; Szelezniak, Michal; Videbaek, Flemming; Vu, Chinh; Wieman, Howard; Woodmansee, Sam
For the 2014 heavy ion run of RHIC a new micro-vertex detector called the Heavy Flavor Tracker (HFT) was installed in the STAR experiment. The HFT consists of three detector subsystems with various silicon technologies arranged in 4 approximately concentric cylinders close to the STAR interaction point designed to improve the STAR detector's vertex resolution and extend its measurement capabilities in the heavy flavor domain. The two innermost HFT layers are placed at radii of 2.8 cm and 8 cm from the beam line. These layers are constructed with 400 high resolution sensors based on CMOS Monolithic Active Pixel Sensor (MAPS) technology arranged in 10-sensor ladders mounted on 10 thin carbon fiber sectors to cover a total silicon area of 0.16 m2. Each sensor of this PiXeL ("PXL") sub-detector combines a pixel array of 928 rows and 960 columns with a 20.7 μm pixel pitch together with front-end electronics and zero-suppression circuitry in one silicon die providing a sensitive area of ˜3.8 cm2. This sensor architecture features 185.6 μs readout time and 170 mW/cm2 power dissipation. This low power dissipation allows the PXL detector to be air-cooled, and with the sensors thinned down to 50 μm results in a global material budget of only 0.4% radiation length per layer. A novel mechanical approach to detector insertion allows us to effectively install and integrate the PXL sub-detector within a 12 hour period during an on-going multi-month data taking period. The detector requirements, architecture and design, as well as the performance after installation, are presented in this paper.
Witten's cubic vertex in the comma theory (I)
Abdurrahman, A.; Bordes Villagrasa, José M.
2001-01-01
In is shown explicitly that the Witten's interaction 3-vertex is a solution to the comma overlap equations; hence establishing the equivalence between the conventional and the "comma" formulation of interacting string theory at the level of vertices.
A new method for computing the quark-gluon vertex
Aguilar, A C
2015-01-01
In this talk we present a new method for determining the nonperturbative quark-gluon vertex, which constitutes a crucial ingredient for a variety of theoretical and phenomenological studies. This new method relies heavily on the exact all-order relation connecting the conventional quark-gluon vertex with the corresponding vertex of the background field method, which is Abelian-like. The longitudinal part of this latter quantity is fixed using the standard gauge technique, whereas the transverse is estimated with the help of the so-called transverse Ward identities. This method allows the approximate determination of the nonperturbative behavior of all twelve form factors comprising the quark-gluon vertex, for arbitrary values of the momenta. Numerical results are presented for the form factors in three special kinematical configurations (soft gluon and quark symmetric limit, zero quark momentum), and compared with the corresponding lattice data.
A new method for counting trees with vertex partition
Institute of Scientific and Technical Information of China (English)
2008-01-01
A direct and elementary method is provided in this paper for counting trees with vertex partition instead of recursion, generating function, functional equation, Lagrange inversion, and matrix methods used before.
Graph Theory. 2. Vertex Descriptors and Graph Coloring
Directory of Open Access Journals (Sweden)
Lorentz JÄNTSCHI
2002-12-01
Full Text Available This original work presents the construction of a set of ten sequence matrices and their applications for ordering vertices in graphs. For every sequence matrix three ordering criteria are applied: lexicographic ordering, based on strings of numbers, corresponding to every vertex, extracted as rows from sequence matrices; ordering by the sum of path lengths from a given vertex; and ordering by the sum of paths, starting from a given vertex. We also examine a graph that has different orderings for the above criteria. We then proceed to demonstrate that every criterion induced its own partition of graph vertex. We propose the following theoretical result: both LAVS and LVDS criteria generate identical partitioning of vertices in any graph. Finally, a coloring of graph vertices according to introduced ordering criteria was proposed.
Boolean functions with a vertex-transitive group of automorphisms
Czech Academy of Sciences Publication Activity Database
Savický, Petr
-, submitted 2015 (2016) R&D Projects: GA ČR GAP202/10/1333 Institutional support: RVO:67985807 Keywords : Boolean Functions * hypercube * isometric transformation * vertex-transitive group of automorphisms Subject RIV: BA - General Mathematics
Assembling the last module of the vertex locator for LHCb
Maximilien Brice
2007-01-01
The 42nd and final vertex locator module is assembled in the LHCb clean room. This will be used to measure the point at which two protons in the beam collide from the tracks of particles produced in the collision.
Vertex functions at finite momentum: Application to antiferromagnetic quantum criticality
Wölfle, Peter; Abrahams, Elihu
2016-02-01
We analyze the three-point vertex function that describes the coupling of fermionic particle-hole pairs in a metal to spin or charge fluctuations at nonzero momentum. We consider Ward identities, which connect two-particle vertex functions to the self-energy, in the framework of a Hubbard model. These are derived using conservation laws following from local symmetries. The generators considered are the spin density and particle density. It is shown that at certain antiferromagnetic critical points, where the quasiparticle effective mass is diverging, the vertex function describing the coupling of particle-hole pairs to the spin density Fourier component at the antiferromagnetic wave vector is also divergent. Then we give an explicit calculation of the irreducible vertex function for the case of three-dimensional antiferromagnetic fluctuations, and show that it is proportional to the diverging quasiparticle effective mass.
Torus Knots and the Topological Vertex
Jockers, Hans; Soroush, Masoud
2012-01-01
We propose a class of toric Lagrangian A-branes on the resolved conifold that is suitable to describe torus knots on S^3. The key role is played by the SL(2,Z) transformation, which generates a general torus knot from the unknot. Applying the topological vertex to the proposed A-branes, we rederive the colored HOMFLY polynomials for torus knots, in agreement with the Rosso and Jones formula. We show that our A-model construction is mirror symmetric to the B-model analysis of Brini, Eynard and Marino. Comparing to the recent proposal by Aganagic and Vafa for knots on S^3, we demonstrate that the disk amplitude of the A-brane associated to any knot is sufficient to reconstruct the entire B-model spectral curve. Finally, the construction of toric Lagrangian A-branes is generalized to other local toric Calabi-Yau geometries, which paves the road to study knots in other three-manifolds such as lens spaces.
Finding vertex-surjective graph homomorphisms
Golovach, Petr A; Martin, Barnaby; Paulusma, Daniël
2012-01-01
The Surjective Homomorphism problem is to test whether a given graph G called the guest graph allows a vertex-surjective homomorphism to some other given graph H called the host graph. The bijective and injective homomorphism problems can be formulated in terms of spanning subgraphs and subgraphs, and as such their computational complexity has been extensively studied. What about the surjective variant? Because this problem is NP-complete in general, we restrict the guest and the host graph to belong to graph classes G and H, respectively. We determine to what extent a certain choice of G and H influences its computational complexity. We observe that the problem is polynomial-time solvable if H is the class of paths, whereas it is NP-complete if G is the class of paths. Moreover, we show that the problem is even NP-complete on many other elementary graph classes, namely linear forests, unions of complete graphs, cographs, proper interval graphs, split graphs and trees of pathwidth at most 2. In contrast, we p...
Linear Time Vertex Partitioning on Massive Graphs
Mell, Peter; Harang, Richard; Gueye, Assane
2016-01-01
The problem of optimally removing a set of vertices from a graph to minimize the size of the largest resultant component is known to be NP-complete. Prior work has provided near optimal heuristics with a high time complexity that function on up to hundreds of nodes and less optimal but faster techniques that function on up to thousands of nodes. In this work, we analyze how to perform vertex partitioning on massive graphs of tens of millions of nodes. We use a previously known and very simple heuristic technique: iteratively removing the node of largest degree and all of its edges. This approach has an apparent quadratic complexity since, upon removal of a node and adjoining set of edges, the node degree calculations must be updated prior to choosing the next node. However, we describe a linear time complexity solution using an array whose indices map to node degree and whose values are hash tables indicating the presence or absence of a node at that degree value. This approach also has a linear growth with respect to memory usage which is surprising since we lowered the time complexity from quadratic to linear. We empirically demonstrate linear scalability and linear memory usage on random graphs of up to 15000 nodes. We then demonstrate tractability on massive graphs through execution on a graph with 34 million nodes representing Internet wide router connectivity.
Vertex Splitting and Upper Embeddable Graphs
Dong, Guanghua; Huang, Yuanqiu; Ren, Han; Liu, Yanpei
2012-01-01
The weak minor G of a graph G is the graph obtained from G by a sequence of edge-contraction operations on G. A weak-minor-closed family of upper embeddable graphs is a set G of upper embeddable graphs that for each graph G in G, every weak minor of G is also in G. Up to now, there are few results providing the necessary and sufficient conditions for characterizing upper embeddability of graphs. In this paper, we studied the relation between the vertex splitting operation and the upper embeddability of graphs; provided not only a necessary and sufficient condition for characterizing upper embeddability of graphs, but also a way to construct weak-minor-closed family of upper embeddable graphs from the bouquet of circles; extended a result in J: Graph Theory obtained by L. Nebesk{\\P}y. In addition, the algorithm complex of determining the upper embeddability of a graph can be reduced much by the results obtained in this paper.
Braided Tensor Categories and Extensions of Vertex Operator Algebras
Huang, Yi-Zhi; Kirillov, Alexander; Lepowsky, James
2015-08-01
Let V be a vertex operator algebra satisfying suitable conditions such that in particular its module category has a natural vertex tensor category structure, and consequently, a natural braided tensor category structure. We prove that the notions of extension (i.e., enlargement) of V and of commutative associative algebra, with uniqueness of unit and with trivial twist, in the braided tensor category of V-modules are equivalent.
The quintic interaction vertex in light-cone gravity
International Nuclear Information System (INIS)
We consider pure gravity in light-cone gauge and derive the complete quintic interaction vertex. Up to quartic order, the Kawai-Lewellen-Tye (KLT) relations can be made manifest at the level of the Einstein-Hilbert Lagrangian. The quintic interaction vertex represents an essential first step in further extending the off-shell validity of the KLT relations to higher order vertices
The quintic interaction vertex in light-cone gravity
Energy Technology Data Exchange (ETDEWEB)
Ananth, Sudarshan [Indian Institute of Science Education and Research Pune, 411021 (India)], E-mail: ananth@aei.mpg.de
2008-06-19
We consider pure gravity in light-cone gauge and derive the complete quintic interaction vertex. Up to quartic order, the Kawai-Lewellen-Tye (KLT) relations can be made manifest at the level of the Einstein-Hilbert Lagrangian. The quintic interaction vertex represents an essential first step in further extending the off-shell validity of the KLT relations to higher order vertices.
The quintic interaction vertex in light-cone gravity
Ananth, Sudarshan
2008-01-01
We consider pure gravity in light-cone gauge and derive the complete quintic interaction vertex. Up to quartic order, the Kawai-Lewellen-Tye (KLT) relations can be made manifest at the level of the Einstein-Hilbert Lagrangian. The quintic interaction vertex represents an essential first step in further extending the off-shell validity of the KLT relations to higher order vertices.
The vertex detector for the Lepton/Photon collaboration
Energy Technology Data Exchange (ETDEWEB)
Sullivan, J.P.; Boissevain, J.G.; Fox, D.; Hecke, H. van; Jacak, B.V.; Kapustinsky, J.S.; Leitch, M.J.; McGaughey, P.L.; Moss, J.M.; Sondheim, W.E. [Los Alamos National Lab., NM (United States)
1991-12-31
The conceptual design of the vertex detector for the Lepton/Photon Collaboration at RHIC is described, including simulations of its expected performance. The design consists of two con- centric layers of single-sided Si strips. The expected performance as a multiplicity detector and in measuring the pseudo-rapidity ({nu}) distribution is discussed as well as the expected vertex finding efficiency and accuracy. Various options which could be used to reduce the cost of the detector are also discussed.
Decay vertex reconstruction and 3-dimensional lifetime determination at BESⅢ
Institute of Scientific and Technical Information of China (English)
XU Min; HE Kang-Lin; ZHANG Zi-Ping; WANG Yi-Fang; BIAN Jian-Ming; CAO Guo-Fu; CAO Xue-Xiang; CHEN Shen-Jian; DENG Zi-Yan; FU Cheng-Dong; GAO Yuan-Ning; HAN Lei; NAN Shao-Qing; HE Miao; HU Ji-Feng; HU Xiao-Wei; HUANG Bin; HUANG Xing-Tao; JIA Lu-Kui; JI Xiao-Sin; LI Hai-Bo; LI Wei-Dong; LIANG Yu-Wie; LIU Chun-Xiu; LIU Huai-Min; LIU Ying; LIU Yong; LUO Tao; L(U) Qi-Wen; MA Qiu-Mei; MA Xiang; MAO Ya-Jun; MAO Ze-Pu; MO Xiao-Hu; NING Fei-Peng; PING Rong-Gang; QIU Jin-Fa; SONG Wen-Bo; SUN Sheng-Sen; SUN Xiao-Dong; SUN Yong-Zhao; TIAN Hao-Lai; WANG Ji-Ke; WANG Liang-Liang; WEN Shuo-Pin; WU Ling-Hui; WU Zhi; XIE Yu-Guang; YAN Jie; YAN Liang; YAO Jian; YUAN Chang-Zheng; YUAN Ye; ZHANG Chang-Chun; ZHANG Jian-Yong; ZHANG Lei; ZHANG Xue-Yao; ZHANG Yao; ZHENG Yang-Heng; ZHU Yong-Sheng; ZOU Jia-Heng
2009-01-01
This paper focuses mainly on the vertex reconstruction of resonance particles with a relatively long lifetime such as KSO, A, as well as on lifetime measurements using a 3-dimensional fit. The kinematic constraints between the production and decay vertices and the decay vertex fitting algorithm based on the least squares method are both presented. Reconstruction efficiencies including experimental resolutions are discussed. The results and systematic errors are calculated based on a Monte Carlo simulation.
The vertex detector for the Lepton/Photon Collaboration
International Nuclear Information System (INIS)
The conceptual design of the vertex detector for the Lepton/Photon Collaboration at RHIC is described, including simulations of its expected performance. The design consists of two concentric layers of single-sided Si strips. The expected performance as a multiplicity detector and in measuring the pseudo-rapidity η distribution is discussed as well as the expected vertex finding efficiency and accuracy. Various options which could be used to reduce the cost of the detector are also discussed
DISTRIBUTED VERTEX COVER ALGORITHMS FOR WIRELESS SENSOR NETWORKS
Directory of Open Access Journals (Sweden)
Vedat Kavalci
2014-01-01
Full Text Available Vertex covering has important applications for wireless sensor networks such as monitoring link failures, facility location, clustering, and data aggregation. In this study, we designed three algorithms for constructing vertex cover in wireless sensor networks. The first algorithm, which is an adaption of the Parnas & Ron’s algorithm, is a greedy approach that finds a vertex cover by using the degrees of the nodes. The second algorithm finds a vertex cover from graph matching where Hoepman’s weighted matching algorithm is used. The third algorithm firstly forms a breadth-first search tree and then constructs a vertex cover by selecting nodes with predefined levels from breadth-first tree. We show the operation of the designed algorithms, analyze them, and provide the simulation results in the TOSSIM environment. Finally we have implemented, compared and assessed all these approaches. The transmitted message count of the first algorithm is smallest among other algorithms where the third algorithm has turned out to be presenting the best results in vertex cover approximation ratio.
TFA pixel sensor technology for vertex detectors
Jarron, P.; Moraes, D.; Despeisse, M.; Dissertori, G.; Dunand, S.; Kaplon. J.; Miazza, C.; Shah, Arvind; Viertel, G M.; Wyrsch, Nicolas
2008-01-01
Pixel microvertex detectors at the SLHC and a future linear collider face very challenging issues: extreme radiation hardness, cooling design, interconnections density and fabrication cost. As an alternative approach we present a novel pixel detector based on the deposition of a Hydrogenated Amorphous Silicon (a-Si:H) film on top of a readout ASIC. The Thin-Film on ASIC (TFA) technology is inspired by an emerging microelectronic technology envisaged for visible light Active Pixel Sensor (APS)...
Thermal mock-up studies of the DEPFET pixel vertex detector for Belle II
Ye, H; Stever, R; Gadow, K; Camien, C
2016-01-01
The Belle II experiment currently under construction at the $e^+e^-$-collider SuperKEKB in Japan is designed to explore new physics beyond the standard model with an approximately 50 times larger data sample compared to its predecessor. The vertex detector (VXD), comprising a two layer DEPFET pixel detector (PXD) surrounded by four layers of double sided silicon strip detector (SVD), is indispensable for the accurate determination of the decay point of $B$ or $D$ mesons as well as track reconstruction of low momentum particles. In order to guarantee acceptable operation conditions for the VXD and the surrounding Belle II drift-chamber (CDC) the cooling system must be capable of removing a total heat load from the very confined VXD volume of about 1~kW plus some heat intake arising from the SuperKEKB beam pipe. Evaporative two-phase CO$_2$ cooling in combination with forced air flow has been chosen as technology for the VXD cooling system. To verify and optimize the vertex detector cooling concept, a full-size...
Energy Technology Data Exchange (ETDEWEB)
Ganjour, S
2007-09-15
This report summarizes my scientific activities from 1995 to 2007. During this period of time, my research work was related to the particle physics experiment BABAR. The BABAR experiment has been running since 1999 at the PEP-II e{sup +}e{sup -} asymmetric B-factory located at SLAC. This experiment searches for CP violation in the system of B mesons and tests the Standard Model through the measurements of the angles and the sides of the Unitarity Triangle. My research work is divided in five main topics: study of the BABAR magnet system and measurement of the magnetic field in the central tracking volume; project of the particle identification system based on aerogel counters for the forward region of the detector; conception of the magnetic shield and measurements of the fringe field in the region of photomultipliers of the DIRC (Detector of Internally Reflected Cherenkov light) system, the principal particle identification system of BABAR; development of the partial reconstruction technique of B mesons and study of the B{sup 0} {yields} D{sub s}{sup *} + D{sup *-} decays; measurement of CP violation in the B{sup 0} {yields} D{sup *{+-}}{pi}{sup {+-}} decays and constraint on the Unitary Triangle parameter sin(2{beta} + {gamma}) using these decays. (author)
CDF Run IIb silicon: Stave design and testing
Energy Technology Data Exchange (ETDEWEB)
Rong-Shyang Lu
2003-11-07
The CDF Silicon Vertex Detectors (SVX) have been shown to be excellent tools for heavy flavor physics, with the secondary vertex detection and good vertex resolution.The CDF RunIIb Silicon Vertex Detector (SVXIIb) was designed to be a radiation tolerant replacement for the current SVXII which was not anticipated to survive the projected Run II luminosity dose. The outer five layers use identical structural elements, called staves, to support six silicon sensors on each side. The stave is composed of carbon fiber skins on a foam core with a built-in cooling tube. Copper on Kapton bus cable carriers power and data/control signals underneath three silicon modules on each side of the stave. A Hybrid equipped with four new SVX4 chips are used to readout two silicon sensors on each module which can be readout and tested independently. This new design concept leads to a very compact mechanical and electrical detecting unit, allowing streamline production and ease of testing and installation. A description of the design and mechanical performance of the stave is given. They also present here results on the electrical performance obtained using prototype staves as well as results with the first pre-production parts.
Childers, Annie Burns; Vidakovic, Draga
2014-01-01
This paper explores sixty-six students' personal meaning and interpretation of the vertex of a quadratic function in relation to their understanding of quadratic functions in two different representations, algebraic and word problem. Several categories emerged from students' personal meaning of the vertex including vertex as maximum or…
Silicon tracking detectors in high-energy physics
International Nuclear Information System (INIS)
Since the fifties, semiconductors have been used as energy spectrometers, mainly in unsegmented ways. With the planar technique of processing silicon sensors in unprecedented precession, strip-like segmentation has allowed precise tracking and even vertexing, culminating in the early eighties with NA11 in the tagging of heavy flavor quarks - here the c-quark. With the later miniaturization of electronics, dense detector application was made possible, and large-scale systems were established in the heart of all LEP detectors, permitting vertexing in barrel-like detectors. At the time of LEP and the TEVATRON, tasks were still bifurcated. Small silicon detectors (up to three layers) did the vertexing and further out, gaseous detectors (e.g., drift chambers or time-projection chambers) with larger lever arms did the tracking. In RUN II of the CDF detector, larger silicon tracking devices, still complemented by a huge drift chamber, began to use a stand-alone tracking. At the LHC, ATLAS and CMS bifurcate in a slightly different way. Silicon pixel detectors are responsible for the vertexing, and large volume silicon strip detectors (up to 14 layers) are the main tracking devices. Silicon tracking systems are a fundamental part of modern multipurpose high-energy physics experiments. Despite the vertexing and thus the heavy quark tagging, silicon tracking detectors in combination with a strong B-field deliver the most accurate momentum measurement, and for a large range, also the best energy measurement. In this paper, the functionality of pixel and strip sensors will be introduced, and historical examples will be given to highlight the different implementations of the past 30 years.
Recent results on two-photon physics at BABAR
International Nuclear Information System (INIS)
Two-photon processes produced at e+e- colliders via the reaction e+ e- → e+ e- γ γ* → e+ e- X, provide important experimental data for the study of hadronic spectra and testing QCD predictions. We report here on recent results in a number of these channels that are obtained at the PEP-II collider with the BABAR detector. The γγ → π0π0, π0η, and ηη cross sections are measured in the two photon invariant mass range from 2 GeV to 5 GeV using both single tag and no tag techniques. We also present measurements of the photon-meson transition form factors using the single tag technique. The γγ* → π0 transition form factor for the momentum transfer range Q2=4-40 GeV2 and the γγ* → ηc transition form factor for the range Q2=2-50 GeV2 will be presented. (author)
The BABAR Database：Challenges,Trends and Projections
Institute of Scientific and Technical Information of China (English)
I.Gaponenko; A.Adesanya; 等
2001-01-01
The BABAR database,based upon the Objectivity OO database management system,has been in production since early 1999,It has met its initial design requirements which were to accommodate a 100Hz event rate from the experiment at a scale of 200TB per year.However,with increased luminosity and changes in the physics requirements,these requirements have increased significantly for the current running period and will again increase in the future.New capabilities in the underlying ODBMS product,in particular those of multiple federation and read-only database support,have been incorporated into a new design that is backwards compatible with existing application code while offering scaling into the multi-petabyte size regime.Other optimizations,including the increased use of thghtly coupled CORBA servers and an improved awareness of space inefficiencies,are also playing a part in meeting the new scaling requirements.We discuss these optimizations and the prospects for further scaling enhancements to address the longer-term needs of the experiment.
The BaBar Data Reconstruction Control System
Energy Technology Data Exchange (ETDEWEB)
Ceseracciu, A
2005-04-20
The BaBar experiment is characterized by extremely high luminosity and very large volume of data produced and stored, with increasing computing requirements each year. To fulfill these requirements a Control System has been designed and developed for the offline distributed data reconstruction system. The control system described in this paper provides the performance and flexibility needed to manage a large number of small computing farms, and takes full benefit of OO design. The infrastructure is well isolated from the processing layer, it is generic and flexible, based on a light framework providing message passing and cooperative multitasking. The system is distributed in a hierarchical way: the top-level system is organized in farms, farms in services, and services in subservices or code modules. It provides a powerful Finite State Machine framework to describe custom processing models in a simple regular language. This paper describes the design and evolution of this control system, currently in use at SLAC and Padova on {approx}450 CPUs organized in 9 farms.
Recent Results in Semileptonic B Decays with BaBar
Energy Technology Data Exchange (ETDEWEB)
Hamilton, B.K.; /Maryland U.
2012-04-02
In this note, recent results of studies of semileptonic B meson decays from BABAR are discussed and preliminary results given. In particular, a recent measurement of {Beta}(B {yields} D{sup (*)}{tau}{nu}) and the ratio {Beta}(B {yields} D{sup (*)}{tau}{nu})/{Beta}(B {yields} D{sup (*)}{ell}{nu}) is presented. For the D* mode, a branching fraction of 1.79 {+-} 0.13(stat) {+-} 0.17(syst) is found, with a ratio of 0.325 {+-} 0.023(stat) {+-} 0.027(syst). For the D mode, the results are 1.04 {+-} 0.12(stat) {+-} 0.14(syst) and 0.456 {+-} 0.053(stat) {+-} 0.056(syst), respectively. In addition, a study of B{sub s} production and semileptonic decays using data collected in a center-of-mass energy region above the {Upsilon}(4S) resonance is discussed. The semileptonic branching fraction {Beta}(B{sub s} {yields} {ell}{nu}X) is measured to be 9.9{sub -2.1}{sup +2.6}(stat){sub -2.0}{sup +1.3}(syst).
Production and decay of Xic0 at BABAR
Aubert, B; Boutigny, D; Couderc, F; Karyotakis, Yu; Lees, J P; Poireau, V; Tisserand, V; Zghiche, A; Graugès-Pous, E; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, Michael T; Wenzel, W A; Barrett, M; Ford, K E; Harrison, T J; Hart, A J; Hawkes, C M; Morgan, S E; Watson, A T; Fritsch, M; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Schröder, T; Steinke, M; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; Wilson, F F; Çuhadar-Dönszelmann, T; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Thiessen, D; Khan, A; Kyberd, P; Teodorescu, L; Blinov, A E; Blinov, V E; Druzhinin, V P; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bruinsma, M; Chao, M; Eschrich, I; Kirkby, D; Lankford, A J; Mandelkern, M A; Mommsen, R K; Röthel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Weinstein, A J R; Foulkes, S D; Gary, J W; Long, O; Shen, B C; Wang, K; Del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Eisner, A M; Heusch, C A; Kroseberg, J; Lockman, W S; Nesom, G; Schalk, T; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S M; Mancinelli, G; Meadows, B T; Sokoloff, M D; Blanc, F; Bloom, P; Chen, S; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Ruddick, W O; Smith, J G; Ulmer, K A; Zhang, J; Zhang, L; Chen, A; Eckhart, E A; Harton, J L; Soffer, A; Toki, W H; Wilson, R J; Zeng, Q; Spaan, B; Altenburg, D; Brandt, T; Brose, J; Dickopp, M; Feltresi, E; Hauke, A; Lacker, H M; Nogowski, R; Otto, S; Petzold, A; Schubert, J; Schubert, Klaus R; Schwierz, R; Sundermann, J E; Bernard, D; Bonneaud, G R; Grenier, P; Schrenk, S; Thiebaux, C; Vasileiadis, G; Verderi, M; Bard, D J; Clark, P J; Muheim, F; Playfer, S; Xie, Y; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Treadwell, E; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; De, R; Sangro; Finocchiaro, G; Patteri, P; Peruzzi, I M; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Crosetti, G; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Brandenburg, G; Chaisanguanthum, K S; Morii, M; Won, E; Dubitzky, R S; Langenegger, U; Marks, J; Uwer, U; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Gaillard, J R; Morton, G W; Nash, J A; Nikolich, M B; Taylor, G P; Charles, M J; Grenier, G J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Yi, J; Biasini, M; Covarelli, R; Pioppi, M; Arnaud, N; Davier, M; Giroux, X; Grosdidier, G; Höcker, A; Le Diberder, F R; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Wormser, G; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Chavez, C A; Coleman, J P; Forster, I J; Fry, J R; Gabathuler, Erwin; Gamet, R; Hutchcroft, D E; Parry, R J; Payne, D J; Touramanis, C; Cormack, C M; Di Lodovico, F; Brown, C L; Cowan, G; Flack, R L; Flächer, H U; Green, M G; Jackson, P S; McMahon, T R; Ricciardi, S; Salvatore, F; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hodgkinson, M C; Lafferty, G D; Williams, J C; Chen, C; Farbin, A; Hulsbergen, W D; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Stängle, H; Willocq, S; Cowan, R; Koeneke, K; Sciolla, G; Sekula, S J; Taylor, F; Yamamoto, R K; Patel, P M; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L M; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Taras, P; Nicholson, H; Cavallo, N; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M; Bulten, H; Raven, G; Snoek, H L; Wilden, L; Jessop, C P; LoSecco, J M; Allmendinger, T; Benelli, G; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pulliam, T; Rahimi, A M; Ter-Antonian, R; Wong, Q K; Brau, J E; Frey, R; Igonkina, O; Lu, M; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; La Vaissière, C de; Del Buono, L; Hamon, O; John, M J J; Leruste, P; Malcles, J; Ocariz, J; Roos, L; Therin, G; Behera, P K; Gladney, L; Guo, Q H; Panetta, J; Angelini, C; Batignani, G; Bettarini, S; Bondioli, M; Bucci, F; Calderini, G; Carpinelli, M; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Simi, G; Walsh, J; Haire, M; Judd, D; Paick, K; Wagoner, D E; Danielson, N; Elmer, P; Lau, Y P; Lü, C; Miftakov, V; Olsen, J; Smith, A J S; Telnov, A V; Bellini, F; Cavoto, G; D'Orazio, A; Di Marco, E; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Li Gioi, L; Mazzoni, M A; Morganti, S; Pierini, M; Piredda, G; Polci, F; Safai-Tehrani, F; Voena, C; Christ, S; Schröder, H; Wagner, G; Waldi, R; Adye, T; De Groot, N; Franek, B J; Gopal, G P; Olaiya, E O; Aleksan, Roy; Emery, S; Gaidot, A; Ganzhur, S F; Giraud, P F; Hamel de Monchenault, G; Kozanecki, Witold; Legendre, M; London, G W; Mayer, B; Schott, G; Vasseur, G; Yéche, C; Zito, M; Purohit, M V; Weidemann, A W; Wilson, J R; Yumiceva, F X; Abe, T; Allen, M; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmüller, O L; Claus, R; Convery, M R; Cristinziani, M; De Nardo, Gallieno; Dingfelder, J C; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W M; Fan, S; Field, R C; Glanzman, T; Gowdy, S J; Hadig, T; Halyo, V; Hast, C; Hrynóva, T; Innes, W R; Kelsey, M H; Kim, P; Kocian, M L; Leith, D W G S; Libby, J; Luitz, S; Lüth, V; Lynch, H L; Marsiske, H; Messner, R; Müller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Soha, A; Stelzer, J; Strube, J; Su, D; Sullivan, M K; Thompson, J; Vavra, J; Wagner, S R; Weaver, M; Wisniewski, W J; Wittgen, M; Wright, D H; Yarritu, A K; Young, C C; Burchat, Patricia R; Edwards, A J; Majewski, S A; Petersen, B A; Roat, C; Ahmed, M; Ahmed, S; Alam, M S; Ernst, J A; Saeed, M A; Saleem, M; Wappler, F R; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Kim, H; Ritchie, J L; Satpathy, A; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bóna, M; Gallo, F; Gamba, D; Bosisio, L; Cartaro, C; Cossutti, F; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Poropat, P; Vitale, L; Vuagnin, G; Martínez-Vidal, F; Panvini, R S; Banerjee, Sw; Bhuyan, B; Brown, C M; Fortin, D; Jackson, P D; Kowalewski, R V; Roney, J M; Sobie, R J; Back, J J; Harrison, P F; Mohanty, G B; Band, H R; Chen, X; Cheng, B; Dasu, S; Datta, M; Eichenbaum, A M; Flood, K T; Graham, M; Hollar, J J; Johnson, J R; Kutter, P E; Li, H; Liu, R; Mihályi, A; Pan, Y; Prepost, R; Tan, P; Von Wimmersperg-Töller, J H; Wu, J; Wu, S L; Yu, Z; Greene, M G; Neal, H
2005-01-01
Using 116.1 fb^-1 of data collected by the BABAR detector, we present an analysis of Xic0 production in B decays and from the ccbar continuum, with the Xic0 decaying into Omega- K+ and Xi- pi+ final states. We measure the ratio of branching fractions B(Xic0 -> Omega- K+)/B(Xic0 -> Xi- pi+) to be 0.294 +- 0.018 +- 0.016, where the first uncertainty is statistical and the second is systematic. The Xic0 momentum spectrum is measured on and 40 MeV below the Upsilon(4S) resonance. From these spectra the branching fraction product B(B -> Xic0 X) x B(Xic0 -> Xi- pi+) is measured to be (2.11 +- 0.19 +- 0.25) x 10^-4 and the cross-section product sigma(e+ e- -> Xic0 X) x B(Xic0 -> Xi- pi+) from the continuum is measured to be (388 +- 39 +- 41) fb at a center-of-mass energy of 10.58 GeV.
Non-linear centre of gravity on LHCb Vertex Locator test beam data
International Nuclear Information System (INIS)
Cluster position reconstruction for the LHCb Vertex Locator test beam software currently uses a linear centre of gravity algorithm. To investigate possible improvements of this approach, a study was performed that made use of a non-linear centre-of-gravity algorithm. All of the sensors in this study were Timepix chips with a 300 μ m layer of p-on-n silicon. The position resolutions obtained with the linear centre-of-gravity ranged between 5.5 μ m and 6.1 μ m. Applying the tuned non-linear algorithm reduces these by at least 0.6 μ m
Test results of the Data Handling Processor for the DEPFET Pixel Vertex Detector
Lemarenko, M.; Hemperek, T.; Krüger, H.; Koch, M.; Lütticke, F.; Marinas, C.; Wermes, N.
2013-01-01
In the new Belle II detector, which is currently under construction at the SuperKEKB accelerator, a two layer pixel detector will be introduced to improve the vertex reconstruction in a ultra high luminosity environment. The pixel detector will be produced using the DEPFET technology. A new ASIC (Data Handling Processor or DHP) designed to steer the readout process, pre-process and compress the raw data has been developed. The DHP will be directly bump bonded to the balcony of the all-silicon DEPFET module. The current chip prototype has been produced in CMOS 90 nm. Its test results, including the data processing quality, the signal integrity of the gigabit transmission lines will be presented here. For the final chip, which will be produced using CMOS 65 nm, single event upset (SEU) cross sections were measured. An additional chip, containing memory blocks to be tested, was submitted and produced using this technology.
The Belle II DEPFET pixel vertex detector. Development of a full-scale module prototype
International Nuclear Information System (INIS)
The Belle II experiment, which will start after 2015 at the SuperKEKB accelerator in Japan, will focus on the precision measurement of the CP-violation mechanism and on the search for physics beyond the Standard Model. A new detection system with an excellent spatial resolution and capable of coping with considerably increased background is required. To address this challenge, a pixel detector based on DEPFET technology has been proposed. A new all silicon integrated circuit, called Data Handling Processor (DHP), is implemented in 65 nm CMOS technology. It is designed to steer the detector and preprocess the generated data. The scope of this thesis covers DHP tests and optimization as well the development of its test environment, which is the first Full-Scale Module Prototype of the DEPFET Pixel Vertex detector.
Performance of the reconstruction algorithms of the FIRST experiment pixel sensors vertex detector
Rescigno, R; Juliani, D; Spiriti, E; Baudot, J; Abou-Haidar, Z; Agodi, C; Alvarez, M A G; Aumann, T; Battistoni, G; Bocci, A; Böhlen, T T; Boudard, A; Brunetti, A; Carpinelli, M; Cirrone, G A P; Cortes-Giraldo, M A; Cuttone, G; De Napoli, M; Durante, M; Gallardo, M I; Golosio, B; Iarocci, E; Iazzi, F; Ickert, G; Introzzi, R; Krimmer, J; Kurz, N; Labalme, M; Leifels, Y; Le Fevre, A; Leray, S; Marchetto, F; Monaco, V; Morone, M C; Oliva, P; Paoloni, A; Patera, V; Piersanti, L; Pleskac, R; Quesada, J M; Randazzo, N; Romano, F; Rossi, D; Rousseau, M; Sacchi, R; Sala, P; Sarti, A; Scheidenberger, C; Schuy, C; Sciubba, A; Sfienti, C; Simon, H; Sipala, V; Tropea, S; Vanstalle, M; Younis, H
2014-01-01
Hadrontherapy treatments use charged particles (e.g. protons and carbon ions) to treat tumors. During a therapeutic treatment with carbon ions, the beam undergoes nuclear fragmentation processes giving rise to significant yields of secondary charged particles. An accurate prediction of these production rates is necessary to estimate precisely the dose deposited into the tumours and the surrounding healthy tissues. Nowadays, a limited set of double differential carbon fragmentation cross-section is available. Experimental data are necessary to benchmark Monte Carlo simulations for their use in hadrontherapy. The purpose of the FIRST experiment is to study nuclear fragmentation processes of ions with kinetic energy in the range from 100 to 1000 MeV/u. Tracks are reconstructed using information from a pixel silicon detector based on the CMOS technology. The performances achieved using this device for hadrontherapy purpose are discussed. For each reconstruction step (clustering, tracking and vertexing), different...
Recent results with HV-CMOS and planar sensors for the CLIC vertex detector
AUTHOR|(SzGeCERN)734627
2016-01-01
The physics aims for the future multi-TeV e+e- Compact Linear Collider (CLIC) impose high precision requirements on the vertex detector which has to match the experimental conditions, such as the time structure of the collisions and the presence of beam-induced backgrounds. The principal challenges are: a point resolution of 3μm, 10 ns time stamping capabilities, low mass (⇠0.2% X0 per layer), low power dissipation and pulsed power operation. Recent results of test beam measurements and GEANT4 simulations for assemblies with Timepix3 ASICs and thin active-edge sensors are presented. The 65 nm CLICpix readout ASIC with 25μm pitch was bump bonded to planar silicon sensors and also capacitively coupled through a thin layer of glue to active HV-CMOS sensors. Test beam results for these two hybridisation concepts are presented.
Development of CMOS pixel sensors for tracking and vertexing in high energy physics experiments
Senyukov, Serhiy; Besson, Auguste; Claus, Giles; Cousin, Loic; Dulinski, Wojciech; Goffe, Mathieu; Hippolyte, Boris; Maria, Robert; Molnar, Levente; Castro, Xitzel Sanchez; Winter, Marc
2014-01-01
CMOS pixel sensors (CPS) represent a novel technological approach to building charged particle detectors. CMOS processes allow to integrate a sensing volume and readout electronics in a single silicon die allowing to build sensors with a small pixel pitch ($\\sim 20 \\mu m$) and low material budget ($\\sim 0.2-0.3\\% X_0$) per layer. These characteristics make CPS an attractive option for vertexing and tracking systems of high energy physics experiments. Moreover, thanks to the mass production industrial CMOS processes used for the manufacturing of CPS the fabrication construction cost can be significantly reduced in comparison to more standard semiconductor technologies. However, the attainable performance level of the CPS in terms of radiation hardness and readout speed is mostly determined by the fabrication parameters of the CMOS processes available on the market rather than by the CPS intrinsic potential. The permanent evolution of commercial CMOS processes towards smaller feature sizes and high resistivity ...
International Nuclear Information System (INIS)
The future TeV-scale linear collider ILC (International Linear Collider) offers a large variety of precision measurements complementary to the discovery potential of the LHC (Large Hadron Collider). To fully exploit its physics potential, a vertex detector with unprecedented performance is needed. One proposed technology for the ILC vertex detector is the DEPFET active pixel sensor. The DEPFET sensor offers particle detection with in-pixel amplification by incorporating a field effect transistor into a fully depleted high-ohmic silicon substrate. The device provides an excellent signal-to-noise ratio and a good spatial resolution at the same time. To establish a very fast readout of a DEPFET pixel matrix with row rates of 20 MHz and more, the 128 channel CURO II ASIC has been designed and fabricated. The architecture of the chip is completely based on current mode techniques (SI) perfectly adapted to the current signal of the sensor. For the ILC vertex detector a prototype system with a 64 x 128 DEPFET pixel matrix read out by the CURO II chip has been developed. The design issues and the standalone performance of the readout chip as well as first results with the prototype system will be presented. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Trimpl, M.
2005-12-15
The future TeV-scale linear collider ILC (International Linear Collider) offers a large variety of precision measurements complementary to the discovery potential of the LHC (Large Hadron Collider). To fully exploit its physics potential, a vertex detector with unprecedented performance is needed. One proposed technology for the ILC vertex detector is the DEPFET active pixel sensor. The DEPFET sensor offers particle detection with in-pixel amplification by incorporating a field effect transistor into a fully depleted high-ohmic silicon substrate. The device provides an excellent signal-to-noise ratio and a good spatial resolution at the same time. To establish a very fast readout of a DEPFET pixel matrix with row rates of 20 MHz and more, the 128 channel CURO II ASIC has been designed and fabricated. The architecture of the chip is completely based on current mode techniques (SI) perfectly adapted to the current signal of the sensor. For the ILC vertex detector a prototype system with a 64 x 128 DEPFET pixel matrix read out by the CURO II chip has been developed. The design issues and the standalone performance of the readout chip as well as first results with the prototype system will be presented. (orig.)
On trees with total domination number equal to edge-vertex domination number plus one
Indian Academy of Sciences (India)
B Krishnakumari; Y B Venkatakrishnan; Marcin Krzywkowski
2016-05-01
An edge $e \\in E(G)$ dominates a vertex $v \\in V(G)$ if $e$ is incident with $v$ or $e$ is incident with a vertex adjacent to $v$. An edge-vertex dominating set of a graph $G$ is a set $D$ of edges of $G$ such that every vertex of $G$ is edge-vertex dominated by an edge of $D$. The edge-vertex domination number of a graph $G$ is the minimum cardinality of an edge-vertex dominating set of $G$. A subset $D \\subseteq V(G)$ is a total dominating set of $G$ if every vertex of $G$ has a neighbor in $D$. The total domination number of $G$ is the minimum cardinality of a total dominating set of $G$. We characterize all trees with total domination number equal to edge-vertex domination number plus one.
A covariant representation of the Ball–Chiu vertex
International Nuclear Information System (INIS)
In nonabelian gauge theory the three-gluon vertex function contains important structural information, in particular on infrared divergences, and is also an essential ingredient in the Schwinger–Dyson equations. Much effort has gone into analyzing its general structure, and at the one-loop level also a number of explicit computations have been done, using various approaches. Here we use the string-inspired formalism to unify the calculations of the scalar, spinor and gluon loop contributions to the one-loop vertex, leading to an extremely compact representation in all cases. The vertex is computed fully off-shell and in dimensionally continued form, so that it can be used as a building block for higher-loop calculations. We find that the Bern–Kosower loop replacement rules, originally derived for the on-shell case, hold off-shell as well. We explain the relation of the structure of this representation to the low-energy effective action, and establish the precise connection with the standard Ball–Chiu decomposition of the vertex. This allows us also to predict that the vanishing of the completely antisymmetric coefficient function S of this decomposition is not a one-loop accident, but persists at higher-loop orders. The sum rule found by Binger and Brodsky, which leads to the vanishing of the one-loop vertex in N=4 SYM theory, in the present approach relates to worldline supersymmetry
Overview of Silicon Detectors in STAR: Present and Future
Energy Technology Data Exchange (ETDEWEB)
Kabana, Sonia [Laboratoire de Physique Subatomique et des technologies associees, SUBATECH, Ecole des Mines, 4 rue Alfred Kastler, 44307 Nantes cedex 3 (France); Collaboration: The SVT, SSD and HFT detector groups of the STAR experiment at RHIC
2011-12-13
The STAR experiment at RHIC aims to study the QCD phase transition and the origin of the spin of the proton. Its main detector for charged particle track reconstruction is a Time Projection Chamber, which has been supplemented with a silicon detector involving two different technologies, in particular double-sided silicon strip and silicon drift technology. STAR is preparing now for a new Silicon Vertex Detector, using double-sided silicon strip, single-sided silicon strip-pads, and CMOS monolithic active pixel sensors technology, planned to take data in 2014. We give an overview of the design, calibration and performances of the silicon detectors used by the STAR experiment in the past and the expected performances of the future silicon detector upgrade.
Overview of Silicon Detectors in STAR: Present and Future
International Nuclear Information System (INIS)
The STAR experiment at RHIC aims to study the QCD phase transition and the origin of the spin of the proton. Its main detector for charged particle track reconstruction is a Time Projection Chamber, which has been supplemented with a silicon detector involving two different technologies, in particular double-sided silicon strip and silicon drift technology. STAR is preparing now for a new Silicon Vertex Detector, using double-sided silicon strip, single-sided silicon strip-pads, and CMOS monolithic active pixel sensors technology, planned to take data in 2014. We give an overview of the design, calibration and performances of the silicon detectors used by the STAR experiment in the past and the expected performances of the future silicon detector upgrade.
Measurement of Rb Using a Vertex Mass Tag
International Nuclear Information System (INIS)
We report a new measurement of Rb=ΓZ0→bbarb /ΓZ0→hadrons using a double tag technique, where the b hemisphere selection is based on the reconstructed mass of the B hadron decay vertex. The measurement was performed using a sample of 130x103 hadronic Z0 events, collected with the SLD detector at SLC. The method utilizes the 3D vertexing abilities of the CCD pixel vertex detector and the small stable SLC beams to obtain a high b -tagging efficiency and purity. We obtain Rb=0.2142±0.0034(stat) ±0.0015(syst)±0.0002( Rc) . copyright 1998 The American Physical Society
Universal vertex-IRF transformation for quantum affine algebras
Energy Technology Data Exchange (ETDEWEB)
Buffenoir, E.; Roche, Ph. [Universite Montpellier 2, CNRS, LPTA, UMR 5207 (France); Terras, V. [Universite de Lyon, ENS Lyon, CNRS, Laboratoire de Physique, UMR 5672, France, on leave of absence from Universite Montpellier 2, CNRS, LPTA, UMR 5207 (France)
2012-10-15
We construct a universal solution of the generalized coboundary equation in the case of quantum affine algebras, which is an extension of our previous work to U{sub q}(A{sub r}{sup (1)}). This universal solution has a simple Gauss decomposition which is constructed using Sevostyanov's characters of twisted quantum Borel algebras. We show that in the evaluation representations it gives a vertex-face transformation between a vertex type solution and a face type solution of the quantum dynamical Yang-Baxter equation. In particular, in the evaluation representation of U{sub q}(A{sub 1}{sup (1)}), it gives Baxter's well-known transformation between the 8-vertex model and the interaction-round-faces (IRF) height model.
Vertex Operators in 4D Quantum Gravity formulated as CFT
Hamada, Ken-ji
2010-01-01
We study vertex operators in 4D conformal field theory derived from quantized gravity, whose dynamics is governed by the Weyl action and the Wess-Zumino action by Riegert. Conformal symmetry is equal to gauge symmetry of diffeomorphism, which mixes positive-metric and negative-metric modes of the gravitational field and thus these modes cannot be treated separately in physical operators. We explicitly construct gravitational vertex operators of the cosmological constant and the Ricci scalar, which are defined as space-time volume integrals of them are invariant under conformal transformations. Short distance singularities of these operator products are computed and it is shown that their coefficients have physically correct sign. Furthermore, we show that conformal algebra holds even in the system perturbed by the cosmological constant vertex operator, as in the case of the Liouville theory shown by Curtright and Thorn.
Plethystic Vertex Operators and Boson-Fermion Correspondences
Fauser, Bertfried; King, Ronald C
2016-01-01
We study the algebraic properties of plethystic vertex operators, introduced in J. Phys. A: Math. Theor. 43 405202 (2010), underlying the structure of symmetric functions associated with certain generalized universal character rings of subgroups of the general linear group, defined to stabilize tensors of Young symmetry type characterized by a partition of arbitrary shape \\pi. Here we establish an extension of the well-known boson-fermion correspondence involving Schur functions and their associated (Bernstein) vertex operators: for each \\pi, the modes generated by the plethystic vertex operators and their suitably constructed duals, satisfy the anticommutation relations of a complex Clifford algebra. The combinatorial manipulations underlying the results involve exchange identities exploiting the Hopf-algebraic structure of certain symmetric function series and their plethysms.
Refined topological vertex, cylindric partitions and U(1) adjoint theory
International Nuclear Information System (INIS)
We study the partition function of the compactified 5D U(1) gauge theory (in the Ω-background) with a single adjoint hypermultiplet, calculated using the refined topological vertex. We show that this partition function is an example a periodic Schur process and is a refinement of the generating function of cylindric plane partitions. The size of the cylinder is given by the mass of adjoint hypermultiplet and the parameters of the Ω-background. We also show that this partition function can be written as a trace of operators which are generalizations of vertex operators studied by Carlsson and Okounkov. In the last part of the paper we describe a way to obtain (q,t) identities using the refined topological vertex.
Recent Charm Physics Results from BaBar
Energy Technology Data Exchange (ETDEWEB)
Neri, Nicola, E-mail: nicola.neri@mi.infn.it
2013-08-15
I present recent results from the BaBar experiment based on a data sample corresponding to an integrated luminosity of about 480 fb{sup −1} collected at the PEP-II asymmetric energy e{sup +}e{sup −} collider. In particular, I will discuss the search for CP violation in D{sup +}→K{sub s}{sup 0}K{sup +} and D{sub s}{sup +}→K{sub s}{sup 0}K{sup +},K{sub s}{sup 0}π{sup +} decays, and in three-body D{sup +}→K{sup +}K{sup −}π{sup +} decays. I will report on the measurement of the mixing parameter y{sub CP} and of the CP-violation parameter ΔY, in the lifetime ratio analysis of the transitions to the CP-even eigenstates D{sup 0}→K{sup +}K{sup −},π{sup +}π{sup −}, relative to the transitions to the CP-mixed state D{sup 0}→K{sup −}π{sup +}, where we obtain y{sub CP}=[0.72±0.18(stat)±0.12(syst)]% and ΔY=[0.09±0.26(stat)±0.06(syst)]%. Finally, I will present a precision measurement of the D{sup ⁎}(2010){sup +} total width, Γ=83.5±1.7(stat)±1.2(syst) keV, and of the D{sup ⁎}(2010){sup +}−D{sup 0} mass difference, Δm=145426.5±0.4(stat)±2.6(syst) keV.
Final Report BaBar Detector and Experimental at SLAC, September 30, 1998 - September 29, 1999
Judd, D J
2000-01-01
The Prairie View AandM University High Energy Physics Group with its contingent of three undergraduates physics majors, joined the BaBar Collaboration at SLAC in September 1994. BaBar is the experiment and detector running in the PEP-II ring at SLAC as part of the Asymmetric B Factory project there to study CP violation and heavy flavor physics. The focus of our effort before this year was with the Muon/Neutral Hadron Detector/Instrumented Flux Return (IFD) subgroup within the BaBar collaboration, and particularly with the GEANT simulation of the IFR-. With the GEANT3 simulation essentially FR-ozen, and the GEANT4 full simulation of the IFR- done, we have decided to redirect our efforts toward other areas.
Final Report: BaBar Detector and Experimental at SLAC, September 30, 1998 - September 29, 1999
International Nuclear Information System (INIS)
The Prairie View AandM University High Energy Physics Group with its contingent of three undergraduates physics majors, joined the BaBar Collaboration at SLAC in September 1994. BaBar is the experiment and detector running in the PEP-II ring at SLAC as part of the Asymmetric B Factory project there to study CP violation and heavy flavor physics. The focus of our effort before this year was with the Muon/Neutral Hadron Detector/Instrumented Flux Return (IFD) subgroup within the BaBar collaboration, and particularly with the GEANT simulation of the IFR-. With the GEANT3 simulation essentially FR-ozen, and the GEANT4 full simulation of the IFR- done, we have decided to redirect our efforts toward other areas
TFA pixel sensor technology for vertex detectors
Energy Technology Data Exchange (ETDEWEB)
Jarron, P. [CERN, CH-1211 Geneva 23 (Switzerland)]. E-mail: Pierre.Jarron@cern.ch; Moraes, D. [CERN, CH-1211 Geneva 23 (Switzerland)]. E-mail: Danielle.Moraes@cern.ch; Despeisse, M. [CERN, CH-1211 Geneva 23 (Switzerland); Dissertori, G. [ETH-Zurich, CH-8093 Zurich (Switzerland); Dunand, S. [IMT, Rue A.-L. Breguet 2, CH-2000 Neuchatel (Switzerland); Kaplon, J. [CERN, CH-1211 Geneva 23 (Switzerland); Miazza, C. [IMT, Rue A.-L. Breguet 2, CH-2000 Neuchatel (Switzerland); Shah, A. [IMT, Rue A.-L. Breguet 2, CH-2000 Neuchatel (Switzerland); Viertel, G.M. [ETH-Zurich, CH-8093 Zurich (Switzerland); Wyrsch, N. [IMT, Rue A.-L. Breguet 2, CH-2000 Neuchatel (Switzerland)
2006-05-01
Pixel microvertex detectors at the SLHC and a future linear collider face very challenging issues: extreme radiation hardness, cooling design, interconnections density and fabrication cost. As an alternative approach we present a novel pixel detector based on the deposition of a Hydrogenated Amorphous Silicon (a-Si:H) film on top of a readout ASIC. The Thin-Film on ASIC (TFA) technology is inspired by an emerging microelectronic technology envisaged for visible light Active Pixel Sensor (APS) devices. We present results obtained with a-Si:H sensor films deposited on a glass substrate and on ASIC, including the radiation hardness of this material up to a fluence of 3.5x10{sup 15} p/cm{sup 2}.
TFA pixel sensor technology for vertex detectors
International Nuclear Information System (INIS)
Pixel microvertex detectors at the SLHC and a future linear collider face very challenging issues: extreme radiation hardness, cooling design, interconnections density and fabrication cost. As an alternative approach we present a novel pixel detector based on the deposition of a Hydrogenated Amorphous Silicon (a-Si:H) film on top of a readout ASIC. The Thin-Film on ASIC (TFA) technology is inspired by an emerging microelectronic technology envisaged for visible light Active Pixel Sensor (APS) devices. We present results obtained with a-Si:H sensor films deposited on a glass substrate and on ASIC, including the radiation hardness of this material up to a fluence of 3.5x1015 p/cm2
Dannheim, D
2014-01-01
A detector concept based on hybrid pixel-detector technology is under development for the CLIC vertex detector. It comprises fast, low-power and small-pitch readout ASICs implemented in 65 nm CMOS technology (CLICpix) coupled to ultra-thin sensors (planar or active HV-CMOS) via low-mass interconnects. The power dissipation of the readout chips is reduced by means of power pulsing, allowing for a cooling system based on forced air flow. In this contribution the CLIC vertex-detector requirements are reviewed and the current status of R&D on readout and sensors is presented.
Vertex-Coloring 2-Edge-Weighting of Graphs
Lu, Hongliang; Zhang, Cun-Quan
2010-01-01
A $k$-{\\it edge-weighting} $w$ of a graph $G$ is an assignment of an integer weight, $w(e)\\in \\{1,\\dots, k\\}$, to each edge $e$. An edge weighting naturally induces a vertex coloring $c$ by defining $c(u)=\\sum_{u\\sim e} w(e)$ for every $u \\in V(G)$. A $k$-edge-weighting of a graph $G$ is \\emph{vertex-coloring} if the induced coloring $c$ is proper, i.e., $c(u) \
Sheaves of N=2 supersymmetric vertex algebras on Poisson manifolds
Ekstrand, Joel; Zabzine, Maxim
2011-01-01
We construct a sheaf of N=2 vertex algebras naturally associated to any Poisson manifold. The relation of this sheaf to the chiral de Rham complex is discussed. We reprove the result about the existence of two commuting N = 2 superconformal structures on the space of sections of the chiral de Rham complex of a Calabi-Yau manifold, but now calculated in a manifest N=2 formalism. We discuss how the semi-classical limit of this sheaf of N=2 vertex algebras is related to the classical supersymmetric non-linear sigma model.
Sheaves of N=2 supersymmetric vertex algebras on Poisson manifolds
Ekstrand, J; R.Heluani; Zabzine, M.
2011-01-01
We construct a sheaf of N=2 vertex algebras naturally associated to any Poisson manifold. The relation of this sheaf to the chiral de Rham complex is discussed. We reprove the result about the existence of two commuting N = 2 superconformal structures on the space of sections of the chiral de Rham complex of a Calabi-Yau manifold, but now calculated in a manifest N=2 formalism. We discuss how the semi-classical limit of this sheaf of N=2 vertex algebras is related to the classical supersymmet...
Simulations with the PANDA micro-vertex-detector
International Nuclear Information System (INIS)
The PANDA experiment will be built at the upcoming FAIR facility at GSI in Darmstadt, featuring antiproton-proton reactions hadron physics in a medium energy range. Charm physics will play an important role and therefore secondary decays relatively close to the interaction zone as well. The MVD will be the detector closest to these and will provide high-quality vertex position measurements. Alongside the detector layout and hardware development a detailed detector simulation and reconstruction software is required. This work contains the detailed description and the performance studies of the software developed for the MVD. Furthermore, vertexing tools are introduced and their performance is studied for the MVD.
CMOS Monolithic Active Pixel Sensors (MAPS) for future vertex detectors
International Nuclear Information System (INIS)
This paper reviews the development of CMOS Monolithic Active Pixel Sensors (MAPS) for future vertex detectors. MAPS are developed in a standard CMOS technology. In the imaging field, where the technology found its first applications, they are also known as CMOS Image Sensors. The use of MAPS as a detector for particle physics was first proposed at the end of 1999. Since then, their good performance in terms of spatial resolution, efficiency, radiation hardness have been demonstrated and work is now well under way to deliver the first MAPS-based vertex detectors
The L3 vertex detector: Design and performance
International Nuclear Information System (INIS)
The L3 vertex detector is comprised of the time expansion chamber (TEC), the Z-chamber and a layer of plastic scintillating fibers. The TEC has shown a high spatial resolution and an excellent multi-track reconstruction capability at LEP luminosity. The Z-chamber provides information about the z-coordinates of the tracks and the fibers are used for calibrating the drift velocity with a high precision. A description of the L3 vertex detector, its readout and data acquisition and its performance during the 1990 LEP running period is presented in this paper. (orig.)
q-vertex operator from 5D Nekrasov function
Itoyama, H.; Oota, T.; Yoshioka, R.
2016-08-01
The five-dimensional AGT correspondence implies the connection between the q-deformed Virasoro block and the 5d Nekrasov partition function. In this paper, we determine a q-deformation of the four-point block in the Coulomb gas representation from the 5d Nekrasov function, and obtain an expression of the q-deformed vertex operator. If we use only one kind of the q-vertex operators, one of the insertion points of them must be modified in order to hold the 2d/5d correspondence.
Simulations with the PANDA micro-vertex-detector
Energy Technology Data Exchange (ETDEWEB)
Kliemt, Ralf
2013-07-17
The PANDA experiment will be built at the upcoming FAIR facility at GSI in Darmstadt, featuring antiproton-proton reactions hadron physics in a medium energy range. Charm physics will play an important role and therefore secondary decays relatively close to the interaction zone as well. The MVD will be the detector closest to these and will provide high-quality vertex position measurements. Alongside the detector layout and hardware development a detailed detector simulation and reconstruction software is required. This work contains the detailed description and the performance studies of the software developed for the MVD. Furthermore, vertexing tools are introduced and their performance is studied for the MVD.
Certain Clifford-like algebra and quantum vertex algebras
Li, Haisheng; Tan, Shaobin; Wang, Qing
2015-01-01
In this paper, we study in the context of quantum vertex algebras a certain Clifford-like algebra introduced by Jing and Nie. We establish bases of PBW type and classify its $\\mathbb N$-graded irreducible modules by using a notion of Verma module. On the other hand, we introduce a new algebra, a twin of the original algebra. Using this new algebra we construct a quantum vertex algebra and we associate $\\mathbb N$-graded modules for Jing-Nie's Clifford-like algebra with $\\phi$-coordinated modu...
CMOS Monolithic Active Pixel Sensors (MAPS) for future vertex detectors
Turchetta, R
2006-01-01
This paper reviews the development of CMOS Monolithic Active Pixel Sensors (MAPS) for future vertex detectors. MAPS are developed in a standard CMOS technology. In the imaging field, where the technology found its first applications, they are also known as CMOS Image Sensors. The use of MAPS as a detector for particle physics was first proposed at the end of 1999. Since then, their good performance in terms of spatial resolution, efficiency, radiation hardness have been demonstrated and work is now well under way to deliver the first MAPS-based vertex detectors.
On the Markov-Dyck shifts of vertex type
Matsumoto, Kengo
2014-01-01
For a given finite directed graph $G$, there are two types of Markov-Dyck shifts, the Markov-Dyck shift $D_G^V$ of vertex type and the Markov-Dyck shift $D_G^E$ of edge type. It is shown that, if $G$ does not have multi-edges, the former is a finite-to-one factor of the latter, and they have the same topological entropy. An expression for the zeta function of a Markov-Dyck shift of vertex type is given. It is different from that of the Markov-Dyck shift of edge type.
The RAVE/VERTIGO vertex reconstruction toolkit and framework
Energy Technology Data Exchange (ETDEWEB)
Waltenberger, W; Mitaroff, W; Moser, F; Pflugfelder, B; Riedel, H V [Austrian Academy of Sciences, Institute of High Energy Physics, A-1050 Vienna (Austria)], E-mail: walten@hephy.oeaw.ac.at
2008-07-15
A detector-independent toolkit for vertex reconstruction (RAVE{sup 1}) is being developed, along with a standalone framework (VERTIGO{sup 2}) for testing, analyzing and debugging. The core algorithms represent state-of-the-art for geometric vertex finding and fitting by both linear (Kalman filter) and robust estimation methods. Main design goals are ease of use, flexibility for embedding into existing software frameworks, extensibility, and openness. The implementation is based on modern object-oriented techniques, is coded in C++ with interfaces for Java and Python, and follows an open-source approach. A beta release is available.
RAVE-a Detector-independent vertex reconstruction toolkit
Energy Technology Data Exchange (ETDEWEB)
Waltenberger, Wolfgang [Institute of High Energy Physics, Austrian Academy of Sciences A-1050 Vienna (Austria)], E-mail: walten@hephy.oeaw.ac.at; Mitaroff, Winfried; Moser, Fabian [Institute of High Energy Physics, Austrian Academy of Sciences A-1050 Vienna (Austria)
2007-10-21
A detector-independent toolkit for vertex reconstruction (RAVE) is being developed, along with a standalone framework (VERTIGO) for testing, analyzing and debugging. The core algorithms represent state of the art for geometric vertex finding and fitting by both linear (Kalman filter) and robust estimation methods. Main design goals are ease of use, flexibility for embedding into existing software frameworks, extensibility, and openness. The implementation is based on modern object-oriented techniques, is coded in C++ with interfaces for Java and Python, and follows an open-source approach. A beta release is available.
The RAVE/VERTIGO vertex reconstruction toolkit and framework
Waltenberger, W.; Mitaroff, W.; Moser, F.; Pflugfelder, B.; Riedel, H. V.
2008-07-01
A detector-independent toolkit for vertex reconstruction (RAVE1) is being developed, along with a standalone framework (VERTIGO2) for testing, analyzing and debugging. The core algorithms represent state-of-the-art for geometric vertex finding and fitting by both linear (Kalman filter) and robust estimation methods. Main design goals are ease of use, flexibility for embedding into existing software frameworks, extensibility, and openness. The implementation is based on modern object-oriented techniques, is coded in C++ with interfaces for Java and Python, and follows an open-source approach. A beta release is available.
Van Bakel, N; Bulten, H J; Feuerstack-Raible, M; Jans, E; Ketel, T; Klous, S; Löchner, S; Sexauer, E; Smale, N J; Snoek, H; Trunk, U; Van Beuzekom, M G; Verkooijen, H
2003-01-01
The Beetle is a 128 channel analog pipelined readout chip which is intended for use in the silicon vertex locator (VELO) of the LHCb experiment at CERN. The Beetle chip is specially designed to withstand high radiation doses. Two Beetle1.1 chips bonded to a silicon strip detector have been tested with minimum ionizing particles. The main goal was to measure the signal-to-noise (S/N) ratio of the Beetle1.1 connected to a prototype VELO detector. Furthermore we investigated the general behaviour of the Beetle1.1. In this note we present the chip architecture, the measured (S/N) numbers as well as some characteristics (e.g. risetime, spillover) of the Beetle1.1 chip. Results from a total ionizing dose irradiation test are reported.
Energy Technology Data Exchange (ETDEWEB)
Bakel, N. van E-mail: nielsvb@nikhef.nl; Baumeister, D.; Beuzekom, M. van; Bulten, H.J.; Feuerstack-Raible, M.; Jans, E.; Ketel, T.; Klous, S.; Loechner, S.; Sexauer, E.; Smale, N.; Snoek, H.; Trunk, U.; Verkooijen, H
2003-08-21
The Beetle is a 128 channel analog pipelined readout chip which is intended for use in the silicon vertex locator (VELO) of the LHCb experiment at CERN. The Beetle chip is specially designed to withstand high radiation doses. Two Beetle1.1 chips bonded to a silicon strip detector have been tested with minimum ionizing particles. The main goal was to measure the signal-to-noise (S/N) ratio of the Beetle1.1 connected to a prototype VELO detector. Furthermore we investigated the general behaviour of the Beetle1.1. In this note we present the chip architecture, the measured (S/N) numbers as well as some characteristics (e.g. risetime, spillover) of the Beetle1.1 chip. Results from a total ionizing dose irradiation test are reported.
International Nuclear Information System (INIS)
The Beetle is a 128 channel analog pipelined readout chip which is intended for use in the silicon vertex locator (VELO) of the LHCb experiment at CERN. The Beetle chip is specially designed to withstand high radiation doses. Two Beetle1.1 chips bonded to a silicon strip detector have been tested with minimum ionizing particles. The main goal was to measure the signal-to-noise (S/N) ratio of the Beetle1.1 connected to a prototype VELO detector. Furthermore we investigated the general behaviour of the Beetle1.1. In this note we present the chip architecture, the measured (S/N) numbers as well as some characteristics (e.g. risetime, spillover) of the Beetle1.1 chip. Results from a total ionizing dose irradiation test are reported
Energy Calibration of the BaBar EMC Using the Pi0 Invariant Mass Method
Energy Technology Data Exchange (ETDEWEB)
Tanner, David J.; /Manchester U.
2007-04-06
The BaBar electromagnetic calorimeter energy calibration method was compared with the local and global peak iteration procedures, of Crystal Barrel and CLEO-II. An investigation was made of the possibility of {Upsilon}(4S) background reduction which could lead to increased statistics over a shorter time interval, for efficient calibration runs. The BaBar software package was used with unreconstructed data to study the energy response of the calorimeter, by utilizing the {pi}{sup 0} mass constraint on pairs of photon clusters.
Status of the DIRC detector at BaBar: early operational experience
International Nuclear Information System (INIS)
A novel type of Cherenkov ring imaging particle identification system (DIRC) based on the detection of ring images produced in long, fused silica radiator bars is being used to provide hadronic particle identification in the BaBar detector at PEP-II. The DIRC concept, design, fabrication, and initial performance will be briefly described. The DIRC is now fully commissioned, and has been operating in the BaBar detector on beam line at the PEP-II B Factory since late Spring 1999
N-string, g-loop vertex for the fermionic string
International Nuclear Information System (INIS)
We construct a N-String, g-loop Vertex for the fermionic string, that is the supersymmetric extension of the analogous bosonic Vertex. As a byproduct we obtain also the g-vacuum for the fermionic string. (orig.)
Future trends of 3D silicon sensors
Da Vià, Cinzia; Boscardin, Maurizio; Dalla Betta, Gian-Franco; Haughton, Iain; Grenier, Philippe; Grinstein, Sebastian; Hansen, Thor-Erik; Hasi, Jasmine; Kenney, Christopher; Kok, Angela; Parker, Sherwood; Pellegrini, Giulio; Povoli, Marco; Tzhnevyi, Vladislav; Watts, Stephen J.
2013-12-01
Vertex detectors for the next LHC experiments upgrades will need to have low mass while at the same time be radiation hard and with sufficient granularity to fulfil the physics challenges of the next decade. Based on the gained experience with 3D silicon sensors for the ATLAS IBL project and the on-going developments on light materials, interconnectivity and cooling, this paper will discuss possible solutions to these requirements.
A time expansion chamber as a vertex detector
International Nuclear Information System (INIS)
A high-resolution drift chamber based on the time expansion principle has been built as a vertex detector for the Mark J experiment at DESY. The chamber design and the associated control and readout system are described. Results on chamber performance obtained from test beam measurements and first results from running at PETRA are reported. (orig.)
On Feedback Vertex Set, New Measure and New Structures
Cao, Yixin; Liu, Yang
2010-01-01
We study the parameterized complexity of the {\\sc feedback vertex set} problem ({\\sc fvs}) on undirected graphs. We approach the problem by considering a variation of it, the {\\sc disjoint feedback vertex set} problem ({\\sc disjoint-fvs}), which finds a disjoint feedback vertex set of size $k$ when a feedback vertex set of a graph is given. We show that {\\sc disjoint-fvs} admits a small kernel, and can be solved in polynomial time when the graph has a special structure that is closely related to the maximum genus of the graph. We then propose a simple branch-and-search process on {\\sc disjoint-fvs}, and introduce a new branch-and-search measure. The branch-and-search process effectively reduces a given graph to a graph with the special structure, and the new measure more precisely evaluates the efficiency of the branch-and-search process. These algorithmic, combinatorial, and topological structural studies enable us to develop an $O(3.83^k kn^2)$ time parameterized algorithm for the general {\\sc fvs} problem,...
Approximations of permutation-symmetric vertex couplings in quantum graphs
Czech Academy of Sciences Publication Activity Database
Exner, Pavel; Turek, Ondřej
Providence : American Mathematical Society, 2006, s. 109-120. - (Contemporary Mathematics. 415). [Quantum Graphs and Their Applications. Snowbird (US), 18.06.2005-24.06.2005] Institutional research plan: CEZ:AV0Z10480505 Keywords : quantum graphs * vertex interaction * approximation Subject RIV: BE - Theoretical Physics
New modular form identities associated to generalized vertex operator algebras
Czech Academy of Sciences Publication Activity Database
Zuevsky, Alexander
2015-01-01
Roč. 16, č. 1 (2015), s. 607-623. ISSN 1787-2405 Institutional support: RVO:67985840 Keywords : vertex operator superalgebras * intertwining operators * Riemann surfaces Subject RIV: BA - General Mathematics Impact factor: 0.229, year: 2014 http://mat76.mat.uni-miskolc.hu/~mnotes/index.php?page=article&name=mmn_1138
Vertex algebra generation of almost holomorphic modular forms
Czech Academy of Sciences Publication Activity Database
Zuevsky, Alexander
2015-01-01
Roč. 31, - (2015), s. 15-23. ISSN 0974-5750 Institutional support: RVO:67985840 Keywords : automorphic forms * non-holomorphic extension of Einstein series * vertex algebra s Subject RIV: BA - General Mathematics http://www.scientificadvances.co.in/abstract/1/157/897
Fast simulation and topological vertex finding in JAVA
International Nuclear Information System (INIS)
An overview of the fast Monte Carlo simulation for NLC detector studies as currently provided in the Java Analysis Studio environment is presented. Special emphasis is given to the simulation of tracks. In addition, the SLD collaboration's topological vertex finding algorithm (ZVTOP) has been implemented in the Java Analysis Studio framework
Inducing $\\pi$-partial characters with a given vertex
Lewis, Mark L
2010-01-01
Let $G$ be a solvable group. Let $p$ be a prime and let $Q$ be a $p$-subgroup of a subgroup $V$. Suppose $\\phi \\in \\ibr G$. If either $|G|$ is odd or $p = 2$, we prove that the number of Brauer characters of $H$ inducing $\\phi$ with vertex $Q$ is at most $|\
Six-Vertex, Loop and Tiling models: Integrability and Combinatorics
Zinn-Justin, P
2009-01-01
This is a review (including some background material) of the author's work and related activity on certain exactly solvable statistical models in two dimensions, including the six-vertex model, loop models and lozenge tilings. Applications to enumerative combinatorics and to algebraic geometry are described.
Redford, S
2015-01-01
The Compact Linear Collider is a candidate to be the next high-energy particle physics collider. Using a novel acceleration technique, electrons and positrons would be brought into collision with a centre-of-mass energy of up to 3 TeV. Despite challenging levels of beam-induced background, this would provide a relatively clean environment in which to perform precision physics measurements. The vertex detector would be crucial in achieving this, and would need to provide accurate particle tracking information to facilitate secondary vertex reconstruction and jet flavour-tagging. With this goal in mind, current technological limits are being stretched to design a low occupancy, low mass and low-power dissipation vertex detector for CLIC. A concept comprising thin hybrid pixel detectors coupled to high- performance readout ASICs, power-pulsing and air-flow cooling is under development. In this paper, the CLIC vertex detector requirements are reviewed and the current status of R&D on sensors, readout, powerin...
AN ONLINE LONGITUDINAL VERTEX AND BUNCH SPECTRUM MONITOR FOR RHIC
International Nuclear Information System (INIS)
The longitudinal bunch profile acquisition system at RHIC was recently upgraded to allow on-line measurements of the bunch spectrum, and collision vertex location and shape. The system allows monitoring the evolution of these properties along the ramp, at transition and rebucketing, and at store conditions. We describe some of the hardware and software changes, and show some applications of the system
Tests of track segment and vertex finding with neural networks
International Nuclear Information System (INIS)
Feed forward neural networks have been trained, using back-propagation, to find the slopes of simulated track segments in a straw chamber and to find the vertex of tracks from both simulated and real events in a more conventional drift chamber geometry. Network architectures, training, and performance are presented. 12 refs., 7 figs
Hyperspherical Integration and the Triple-Cross Vertex Graphs
Laporta, S.
1994-01-01
We have extended the hyperspherical variables method to the analytical calculation of the angular integral of the box graph. We discuss the applications of our results to the analytical calculation of the QED contribution to the electron g-2 of the set of three-loop triple-cross vertex graphs.
The electronics readout system for the OPAL Vertex Drift Chamber
International Nuclear Information System (INIS)
The Vertex Drift Chamber for the OPAL experiment at LEP provides high quality track co-ordinates using multi-hit sub-nanosecond timing to detect the drifted electrons. This paper explains the electronic techniques that have been devised and implemented for the detector. The overall performance of the system is demonstrated with measurements from the final OPAL chamber. (author)
A simple local 3-approximation algorithm for vertex cover
Polishchuk, Valentin; Suomela, Jukka
2009-01-01
We present a local algorithm (constant-time distributed algorithm) for finding a 3-approximate vertex cover in bounded-degree graphs. The algorithm is deterministic, and no auxiliary information besides port numbering is required. (c) 2009 Elsevier B.V. All rights reserved.
Symmetric point quartic gluon vertex and momentum subtraction
Gracey, J A
2014-01-01
We compute the full one loop correction to the quartic vertex of QCD at the fully symmetric point. This allows us to define a new momentum subtraction (MOM) scheme in the class of schemes introduced by Celmaster and Gonsalves. Hence using properties of the renormalization group equation, the two loop renormalization group functions for this scheme are given.
Event reconstruction in the vertex chamber of the KEDR detector
International Nuclear Information System (INIS)
The techniques of cosmic and beam event reconstruction in vertex detector (VD) of KEDR are described in this paper. The information on spatial resolution and detection efficiency of the VD drift tubes was obtained using cosmic events. The results of processing of elastic electron-positron scattering events and multihadron production near J/ψ resonance are presented
A Cohomology Theory of Grading-Restricted Vertex Algebras
Huang, Yi-Zhi
2014-04-01
We introduce a cohomology theory of grading-restricted vertex algebras. To construct the correct cohomologies, we consider linear maps from tensor powers of a grading-restricted vertex algebra to "rational functions valued in the algebraic completion of a module for the algebra," instead of linear maps from tensor powers of the algebra to a module for the algebra. One subtle complication arising from such functions is that we have to carefully address the issue of convergence when we compose these linear maps with vertex operators. In particular, for each , we have an inverse system of nth cohomologies and an additional nth cohomology of a grading-restricted vertex algebra V with coefficients in a V-module W such that is isomorphic to the inverse limit of the inverse system . In the case of n = 2, there is an additional second cohomology denoted by which will be shown in a sequel to the present paper to correspond to what we call square-zero extensions of V and to first order deformations of V when W = V.
Results from the first beam-induced reconstructed tracks in the LHCb vertex locator
Rodrigues, E
2010-01-01
LHCb is a dedicated experiment at the LHC to study CP violation and rare $b$ decays. The vertex locator (VELO) is a silicon strip detector designed to measure precisely the production and decay vertices of $B$-mesons. The detector is positioned at 8 mm of the LHC beams and will operate in an extremely harsh radiation environment. The VELO consists of two retractable detector halves with 21 silicon micro-strip tracking modules each. A module is composed of two n$^+$-on-n 300 $\\mu$m thick half disc sensors with $R$ and $\\Phi$ micro-strip geometry. The detectors are operated in vacuum and a bi-phase CO$_2$ cooling system is used. The full system has been operated since June 2008 and its commissioning experience will be reported. During the LHC synchronization tests in August and September 2008, and June 2009 the LHCb detectors measured secondary particles produced by the interaction of the LHC primary beam on a beam dump. About 50,000 tracks were reconstructed in the VELO and they were used to derive the relativ...
Study of the breaking of the CP symmetry in the BABAR experiment
International Nuclear Information System (INIS)
This report summarizes my scientific activities from 1995 to 2007. During this period of time, my research work was related to the particle physics experiment BABAR. The BABAR experiment has been running since 1999 at the PEP-II e+e- asymmetric B-factory located at SLAC. This experiment searches for CP violation in the system of B mesons and tests the Standard Model through the measurements of the angles and the sides of the Unitarity Triangle. My research work is divided in five main topics: study of the BABAR magnet system and measurement of the magnetic field in the central tracking volume; project of the particle identification system based on aerogel counters for the forward region of the detector; conception of the magnetic shield and measurements of the fringe field in the region of photomultipliers of the DIRC (Detector of Internally Reflected Cherenkov light) system, the principal particle identification system of BABAR; development of the partial reconstruction technique of B mesons and study of the B0 → Ds* + D*- decays; measurement of CP violation in the B0 → D*±π± decays and constraint on the Unitary Triangle parameter sin(2β + γ) using these decays. (author)
Rare Decays and Search for New Physics with BaBar
Bauer, Johannes M.
2006-01-01
Rare B decays permit stringent tests of the Standard Model and allow searches for new physics. Several rare radiative-decay studies of the B meson from the BaBar collaboration are described. So far no sign for new physics was discovered.
Kinematic Fit for the Radiative Bhabha Calibration of BaBar's Electromagnetic Calorimeter
Bauer, Johannes M.
2000-01-01
For the radiative Bhabha calibration of BaBar's electromagnetic calorimeter, the measured energy of a photon cluster is being compared with the energy obtained via a kinematic fit involving other quantities from that event. The details of the fitting algorithm are described in this note, together with its derivation and checks that ensure that the fitting routine is working properly.
Search for Physics Beyond the Standard Model at BaBar and Belle
Directory of Open Access Journals (Sweden)
Calderini G.
2012-06-01
Full Text Available Recent results on the search for new physics at BaBar and Belle B-factories are presented. The search for a light Higgs boson produced in the decay of different γ resonances is shown. In addition, recent measurements aimed to discover invisible final states produced by new physics mechanisms beyond the standard model are presented.
BABAR - the detector for the PEP II B Factory at SLAC
International Nuclear Information System (INIS)
BABAR refers to the detector that is being designed for the PEP II B-Factory at SLAC to perform a comprehensive study of CP violation in B meson decays. The design requirements and the principal detector components are briefly described. A summary of the expected physics performance is presented
Charm and Beauty Production from Secondary Vertexing at HERA
Energy Technology Data Exchange (ETDEWEB)
Thompson, Paul [University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom)
2010-07-01
Measurement of the Charm and Beauty Structure Functions using the H1 Vertex Detector at HERA Inclusive charm and beauty cross sections are measured in e{sup -} p and e{sup +}p neutral current collisions at HERA in the kinematic region of photon virtuality 5 < Q{sup 2} < 2000 GeV{sup 2} and Bjorken scaling variable 0.0002 < x < 0.05. The data were collected with the H1 detector in the years 2006 and 2007 corresponding to an integrated luminosity of 189 pb{sup -1}. The numbers of charm and beauty events are determined using variables reconstructed by the H1 vertex detector including the impact parameter of tracks to the primary vertex and the position of the secondary vertex. The measurements are combined with previous data and compared to QCD predictions. Measurement of Charm and Beauty Jets in Deep Inelastic Scattering at HERA Measurements of the charm and beauty jet cross sections have been made in deep inelastic scattering at HERA for the kinematic region of photon virtuality Q{sup 2} > 6 GeV{sup 2} and elasticity variable 0.07 < y < 0.625 for jets in the laboratory frame with transverse energy E{sub T}{sup jet} > 6 GeV and pseudorapidity -1.0 < {eta}{sup jet} < 1.5. Measurements are also made requiring a jet in the Breit frame with E{sub T}{sup jet} > 6 GeV. The data were collected with the H1 detector in the years 2006 and 2007 corresponding to an integrated luminosity of 189 pb{sup -1}. The number of charm and beauty jets are determined using variables reconstructed by the H1 vertex detector including the impact parameter of tracks to the primary vertex and the position of the secondary vertex. The measurements are compared with QCD predictions and with previous measurements obtained using muon tagging. Charm and beauty production in deep inelastic scattering from inclusive secondary vertexing at ZEUS Charm and beauty production in deep inelastic scattering has been measured with the ZEUS detector using the full HERA II data set. The charm and beauty contents
The BaBar LST Detector High Voltage System: Design And Implementation
Energy Technology Data Exchange (ETDEWEB)
Benelli, G.; Honscheid, K.; Lewis, E.A.; Regensburger, J.J.; Smith, D.S.; /Ohio State U.
2006-08-18
In 2004, the first two sextants of the new Limited Streamer Tube (LST) detector were installed in the BABAR experiment to replace the ageing Resistive Plate Chambers (RPCs) as active detectors for the BABAR Instrumented Flux Return (IFR) muon system. Each streamer tube of the new detector consists of 8 cells. The cell walls are coated with graphite paint and a 100 {micro}m wire forms the anode. These wires are coupled in pairs inside the tubes resulting in 4 independent two-cell segments per LST. High voltage (HV) is applied to the 4 segments through a custom connector that also provides the decoupling capacitor to pick up the detector signals from the anode wires. The BABAR LST detector is operated at 5.5 kV. The high voltage system for the LST detector was designed and built at The Ohio State University (OSU HVPS). Each of the 25 supplies built for BaBar provides 80 output channels with individual current monitoring and overcurrent protection. For each group of 20 channels the HV can be adjusted between 0 and 6 kV. A 4-fold fan-out is integrated in the power supplies to provide a total of 320 outputs. The power supplies are controlled through built-in CANbus and Ethernet (TCP/IP) interfaces. In this presentation we will discuss the design and novel features of the OSU HVPS system and its integration into the BABAR EPICS detector control framework. Experience with the supplies operation during the LST extensive quality control program and their performance during the initial data taking period will be discussed.
The BaBar LST Detector High Voltage System: Design And Implementation
International Nuclear Information System (INIS)
In 2004, the first two sextants of the new Limited Streamer Tube (LST) detector were installed in the BABAR experiment to replace the ageing Resistive Plate Chambers (RPCs) as active detectors for the BABAR Instrumented Flux Return (IFR) muon system. Each streamer tube of the new detector consists of 8 cells. The cell walls are coated with graphite paint and a 100 (micro)m wire forms the anode. These wires are coupled in pairs inside the tubes resulting in 4 independent two-cell segments per LST. High voltage (HV) is applied to the 4 segments through a custom connector that also provides the decoupling capacitor to pick up the detector signals from the anode wires. The BABAR LST detector is operated at 5.5 kV. The high voltage system for the LST detector was designed and built at The Ohio State University (OSU HVPS). Each of the 25 supplies built for BaBar provides 80 output channels with individual current monitoring and overcurrent protection. For each group of 20 channels the HV can be adjusted between 0 and 6 kV. A 4-fold fan-out is integrated in the power supplies to provide a total of 320 outputs. The power supplies are controlled through built-in CANbus and Ethernet (TCP/IP) interfaces. In this presentation we will discuss the design and novel features of the OSU HVPS system and its integration into the BABAR EPICS detector control framework. Experience with the supplies operation during the LST extensive quality control program and their performance during the initial data taking period will be discussed
Maghribi, Mariam N.; Krulevitch, Peter; Hamilton, Julie
2008-12-09
A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.
Maghribi, Mariam N.; Krulevitch, Peter; Hamilton, Julie
2006-12-05
A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.
ATLAS strategy for primary vertex reconstruction during Run-II of the LHC
ATLAS Collaboration; The ATLAS collaboration
2015-01-01
Based on experience gained from run-I of the LHC, the ATLAS vertex reconstruction group has developed a refined primary vertex reconstruction strategy for run-II. With instantaneous luminosity exceeding 10^34 cm-2 s-1, an average of 40 to 50 pp collisions per bunch crossing are expected. Together with the increase of the center-of-mass collision energy from 8 TeV to 13 TeV, this will create a challenging environment for primary vertex pattern recognition. This contribution explains the ATLAS strategy for primary vertex reconstruction in high pile-up conditions. The new approach is based on vertex seeding with a medical-imaging algorithm, adaptive reconstruction of vertex positions, and iterative recombination of occasional split vertices. The mathematical foundation and software implementation of the method are described in detail. Monte Carlo-based estimates of vertex reconstruction performance for LHC run-II are presented.
The N = 1 Triplet Vertex Operator Superalgebras: Twisted Sector
Directory of Open Access Journals (Sweden)
Drazen Adamovic
2008-12-01
Full Text Available We classify irreducible σ-twisted modules for the N = 1 super triplet vertex operator superalgebra SW(m introduced recently [Adamovic D., Milas A., Comm. Math. Phys., to appear, arXiv:0712.0379]. Irreducible graded dimensions of σ-twisted modules are also determined. These results, combined with our previous work in the untwisted case, show that the SL(2,Z-closure of the space spanned by irreducible characters, irreducible supercharacters and σ-twisted irreducible characters is (9m + 3-dimensional. We present strong evidence that this is also the (full space of generalized characters for SW(m. We are also able to relate irreducible SW(m characters to characters for the triplet vertex algebra W(2m + 1, studied in [Adamovic D., Milas A., Adv. Math. 217 (2008, 2664-2699, arXiv:0707.1857].
K-vertex-connectivity minimum augmentation for undirected unweighted graphs
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
For an undirected unweighted graph G0＝(V0,E0) and a positive integer K, the K-vertex-connectivity minimum augmentation problem (K-VCMAP) is to find a minimum set of edges Emin such that the graph H0＝(V0,E0∪Emin) is K-vertex-connected. Results in the literature have given polynomial time algorithms for K-VCMAP in several special cases such as where k≤3, or G0 is a tree. However, it still remains open whether or not there exist polynomial time algorithms for K-VCMAP for any graph G0 and any integer K. In this paper, we settle the problem by describing an efficient algorithm (KUCA) with time-complexity of O(K|V(G0)|5) for the K-VCMAP for any G0 and any positive integer K.
Genus Two Zhu Theory for Vertex Operator Algebras
Gilroy, Thomas
2015-01-01
We consider correlation functions for a vertex operator algebra on a genus two Riemann surface formed by sewing two tori together. We describe a generalisation of genus one Zhu recursion expressing an arbitrary genus two $n$--point correlation function in terms of $(n-1)$--point functions. We consider several applications including the correlation functions for the Heisenberg vertex operator algebra and its modules, Virasoro correlation functions and genus two Ward identities. We derive novel differential equations in terms of a differential operator on the genus two Siegel upper half plane for holomorphic $1$--forms, the normalised bidifferential of the second kind and the Heisenberg partition function. We also prove that the holomorphic mapping from the sewing parameter domain to the Siegel upper half plane is injective but not surjective.
Exploratory study of the 3-gluon vertex on the lattice
Parrinello, C
1994-01-01
We define and evaluate on the lattice the amputated 3-gluon vertex function in momentum space. We give numerical results for 16^3 \\times 40 and 24^3 \\times 40 quenched lattices at \\beta=6.0. A good numerical signal is obtained, at the price of enforcing the gauge-fixing condition with high accuracy. By comparing results from two different lattice volumes, we try to investigate the crucial issue of finite volume effects. We also outline a method for the lattice evaluation of the QCD running coupling constant as defined from the 3-gluon vertex, while being aware that a realistic calculation will require larger \\beta values and very high statistics.
On the zero crossing of the three-gluon vertex
Athenodorou, A; Boucaud, Ph; De Soto, F; Papavassiliou, J; Rodriguez-Quintero, J; Zafeiropoulos, S
2016-01-01
We report on new results on the infrared behaviour of the three-gluon vertex in quenched Quantum Chormodynamics, obtained from large-volume lattice simulations. The main focus of our study is the appearance of the characteristic infrared feature known as 'zero crossing', the origin of which is intimately connected with the nonperturbative masslessness of the Faddeev-Popov ghost. The appearance of this effect is clearly visible in one of the two kinematic configurations analyzed, and its theoretical origin is discussed in the framework of Schwinger-Dyson equations. The effective coupling in the momentum subtraction scheme that corresponds to the three-gluon vertex is constructed, revealing the vanishing of the effective interaction at the exact location of the zero crossing.
Diagonalization of the XXZ Hamiltonian by Vertex Operators
Davies, B; Jimbo, M; Miwa, T; Nakayashiki, A; Davies, Brian; Foda, Omar; Jimbo, Michio; Miwa, Tetsuji; Nakayashiki, Atsushi
1993-01-01
We diagonalize the anti-ferroelectric XXZ-Hamiltonian directly in the thermodynamic limit, where the model becomes invariant under the action of affine U_q( sl(2) ). Our method is based on the representation theory of quantum affine algebras, the related vertex operators and KZ equation, and thereby bypasses the usual process of starting from a finite lattice, taking the thermodynamic limit and filling the Dirac sea. From recent results on the algebraic structure of the corner transfer matrix of the model, we obtain the vacuum vector of the Hamiltonian. The rest of the eigenvectors are obtained by applying the vertex operators, which act as particle creation operators in the space of eigenvectors. We check the agreement of our results with those obtained using the Bethe Ansatz in a number of cases, and with others obtained in the scaling limit --- the $su(2)$-invariant Thirring model.
Worldline calculation of the three-gluon vertex
Energy Technology Data Exchange (ETDEWEB)
Ahmadiniaz, N.; Schubert, C. [Dipartimento di Fisica, Universita di Bologna and INFN Sezione di Bologna Via Irnerio 46, I-40126 Bologna (Italy); Instituto de Fisica y Matematicas Universidad Michoacana de San Nicolas de Hidalgo Apdo. Postal 2-82 C.P. 58040, Morelia, Michoacan (Mexico)
2012-10-23
The three-gluon vertex is a basic object of interest in nonabelian gauge theory. At the one-loop level, it has been calculated and analyzed by a number of authors. Here we use the worldline formalism to unify the calculations of the scalar, spinor and gluon loop contributions to the one-loop vertex, leading to an extremely compact representation in terms of field strength tensors. We verify its equivalence with previously obtained representations, and explain the relation of its structure to the low-energy effective action. The sum rule found by Binger and Brodsky for the scalar, spinor and gluon loop contributions in the present approach relates to worldline supersymmetry.
Recent status of FPCCD vertex detector R&D
Murai, S; Sanuki, T; Miyamoto, A; Sugimoto, Y; Constantino, C; Sato, H; Ikeda, H; Hitoshi, H
2016-01-01
The Fine Pixel CCD (FPCCD) is one of the candidate sensor technologies for the ILC vertex detector. It will be located near interaction point and require high radiation tolerance. It will thus be operated at -40 degree C to improve radiation tolerance. In this paper, we report on the status of neutron radiation tests, on a cooling system using two-phase CO2 with a gas compressor for circulation, and on the mechanical structure of the FPCCD ladders.
Towards automorphic to differential correspondence for vertex algebras
Czech Academy of Sciences Publication Activity Database
Zuevsky, Alexander
New York: AIP Publishing, 2015 - (Mohammad-Djafari, A.; Barbaresco, F.), s. 603-610. (AIP Proceedings. 1641). ISBN 978-0-7354-1280-4. [Bayesian Inference and Maximum Entropy Methods in Science and Engineering (MAXENT 2014) /33./. Amboise (FR), 21.09.2014-26.09.2014] Institutional support: RVO:67985840 Keywords : vertex algebra s * conformal blocks * automorphic forms Subject RIV: BA - General Mathematics http://scitation.aip.org/content/aip/proceeding/aipcp/10.1063/1.4906028
A Gaussian-sum filter for vertex reconstruction
International Nuclear Information System (INIS)
A vertex reconstruction algorithm was developed based on the Gaussian-sum filter and implemented in the framework of the CMS reconstruction program. While linear least-squares estimators are optimal in case all observation errors are Gaussian-distributed, a GSF offers a better treatment of non-Gaussian distributions of track parameter errors when these are modeled by Gaussian mixtures. Results are compared to the Kalman filter
Bethe ansatz for higher spin eight vertex models
Takebe, T
1995-01-01
A generalization of the eight vertex model by means of higher spin representations of the Sklyanin algebra is investigated by the quantum inverse scattering method and the algebraic Bethe Ansatz. Under the well-known string hypothesis low-lying excited states are considered and scattering phase shifts of two physical particles are calculated. The S matrix of two particle states is shown to be proportional to the Baxter's elliptic R matrix with a different elliptic modulus from the original one.
Nonperturbative results on the quark-gluon vertex
Aguilar, A. C.; Binosi, D.; Cardona, J. C.; Papavassiliou, J.
2013-01-01
We present analytical and numerical results for the Dirac form factor of the quark-gluon vertex in the quark symmetric limit, where the incoming and outgoing quark momenta have the same magnitude but opposite sign. To accomplish this, we compute the relevant components of the quark-ghost scattering kernel at the one-loop dressed approximation, using as basic ingredients the full quark propagator, obtained as a solution of the quark gap equation, and the gluon propagator and ghost dressing fun...
A lattice study of the quark propagator and vertex function
Skullerud, Jon Ivar
1994-01-01
We report on the status of a study of the quark propagator and quark-gluon vertex in momentum space. Quark propagators have been generated at beta=6.0 using the O(a)-improved Sheikholeslami-Wohlert action and fixed to the Landau gauge. The first results for the quark pole mass and field renormalisation constant are reported, and plans for future work are presented.
Self-consistency and vertex corrections beyond the GW approximation
Schindlmayr, Arno
2002-01-01
The good performance of the GW approximation for band-structure calculations in solids was long taken as a sign that the sum of self-energy diagrams is converged and that all omitted terms are small. However, with modern computational resources it has now become possible to evaluate self-consistency and vertex corrections explicitly, and the numerical results show that they are, in general, not individually negligible. In this review the available data is examined, and the implications for pr...
Vertex Operators for Irregular Conformal Blocks: Supersymmetric Case
Polyakov, Dimitri
2016-01-01
We construct supersymmetric irregular vertex operators of arbitrary rank, appearing in the colliding limit of primary fields. We find that the structure of the supersymmetric irregular vertices differs significantly from the bosonic case: upon supersymmetrization, the irregular operators are no longer the eigenstates of positive Virasoro and $W_N$ generators but block-diagonalize them. We relate the block-diagonal structure of the irregular vertices to contributions of the Ramond sector to the colliding limit.
Factorized domain wall partition functions in trigonometric vertex models
Foda, O; Zuparic, M
2007-01-01
We obtain factorized domain wall partition functions for two sets of trigonometric vertex models: 1. The N-state Deguchi-Akutsu models, for N = {2, 3, 4} (and conjecture the result for all N >= 5), and 2. The sl(r+1|s+1) Perk-Schultz models, for {r, s = \\N}, where (given the symmetries of these models) the result is independent of {r, s}.
Factorized domain wall partition functions in trigonometric vertex models
Foda, O.; Wheeler, M.; Zuparic, M.
2007-10-01
We obtain factorized domain wall partition functions for two sets of trigonometric vertex models: (1) the N-state Deguchi Akutsu models, for N \\in \\{2, 3, 4\\} (and conjecture the result for all N>=5), and (2) the sl(r+1|s+1) Perk Schultz models, for \\{r, s \\in \\mathbb {N}\\} , where (given the symmetries of these models) the result is independent of {r,s}.
Solving the Generalized Vertex Cover Problem by Genetic Algorithm
Marija Milanović
2012-01-01
In this paper an evolutionary approach to solving the generalized vertex cover problem (GVCP) is presented. Binary representation and standard genetic operators are used along with the appropriate objective function. The experiments were carried out on randomly generated instances with up to 500 vertices and 100000 edges. Performance of the genetic algorithm (GA) is compared with CPLEX solver and 2-approximation algorithm based on LP relaxation. The genetic algorithm outperformed both CPLEX s...
New limits on anomalous contributions to the $Wtb$ vertex
Birman, J.L.; Déliot, F.; Fiolhais, M. C. N.; Onofre, A.; Pease, C. M.
2016-01-01
The latest and most precise top quark measurements at the LHC and Tevatron are used to establish new limits on the $Wtb$ vertex. Recent results on the measurements of the $W$-boson helicity fractions and single top quark production cross section are combined in order to establish new limits at 95% CL (confidence level). The allowed regions for these limits are presented, for the first time, in three-dimensional graphics, for both real and imaginary components of the different anomalous coupli...
Photoabsorption off nuclei with self consistent vertex corrections
Riek, F.; Lutz, M. F. M.; Korpa, C. L.
2008-01-01
We study photoproduction off nuclei based on a self consistent and covariant many body approach for the pion and isobar propagation in infinite nuclear matter. For the first time the t-channel exchange of an in-medium pion is evaluated in the presence of vertex correction effects consistently. In particular the interference pattern with the s-channel in-medium nucleon and isobar exchange contribution is considered. Electromagnetic gauge invariance is kept as a consequence of various Ward iden...
Technical Design Report for the: PANDA Micro Vertex Detector
Erni, W; Krusche, B; Steinacher, M; Heng, Y; Liu, Z; Liu, H; Shen, X; Wang, Q; Xu, H; Albrecht, M; Becker, J; Eickel, K; Feldbauer, F; Fink, M; Friedel, P; Heinsius, F H; Held, T; Koch, H; Kopf, B; Leyhe, M; Motzko, C; Pelizäus, M; Pychy, J; Roth, B; Schröder, T; Schulze, J; Steinke, M; Trifterer, T; Wiedner, U; Zhong, J; Beck, R; Becker, M; Bianco, S; Brinkmann, K -Th; Hammann, C; Hinterberger, F; Jäkel, R; Kaiser, D; Kliemt, R; Koop, K; Schmidt, C; Schnell, R; Thoma, U; Vlasov, P; Wendel, C; Winnebeck, A; Würschig, Th; Zaunick, H -G; Bianconi, A; Bragadireanu, M; Caprini, M; Ciubancan, M; Pantea, D; Tarta, P -D; De Napoli, M; Giacoppo, F; Rapisarda, E; Sfienti, C; Fiutowski, T; Idzik, N; Mindur, B; Przyborowski, D; Swientek, K; Bialkowski, E; Budzanowski, A; Czech, B; Kliczewski, S; Kozela, A; Kulessa, P; Lebiedowicz, P; Malgorzata, K; Pysz, K; Schäfer, W; Siudak, R; Szczurek, A; Brandys, P; Czyzewski, T; Czyzycki, W; Domagala, M; Hawryluk, M; Filo, G; Kwiatkowski, D; Lisowski, E; Lisowski, F; Bardan, W; Gil, D; Kamys, B; Kistryn, St; Korcyl, K; Krzemieñ, W; Magiera, A; Moskal, P; Rudy, Z; Salabura, P; Smyrski, J; Wroñska, A; Al-Turany, M; Arora, R; Augustin, I; Deppe, H; Dutta, D; Flemming, H; Götzen, K; Hohler, G; Karabowicz, R; Lehmann, D; Lewandowski, B; Lühning, J; Maas, F; Orth, H; Peters, K; Saito, T; Schepers, G; Schmidt, C J; Schmitt, L; Schwarz, C; Schwiening, J; Voss, B; Wieczorek, P; Wilms, A; Abazov, V M; Alexeev, G D; Arefiev, V A; Astakhov, V I; Barabanov, M Yu; Batyunya, B V; Davydov, Yu I; Dodokhov, V Kh; Efremov, A A; Fedunov, A G; Feshchenko, A A; Galoyan, A S; Grigoryan, S; Karmokov, A; Koshurnikov, E K; Lobanov, V I; Lobanov, Yu Yu; Makarov, A F; Malinina, L V; Malyshev, V L; Mustafaev, G A; Olshevski, A G; Pasyuk, M A; Perevalova, E A; Piskun, A A; Pocheptsov, T A; Pontecorvo, G; Rodionov, V K; Rogov, Yu N; Salmin, R A; Samartsev, A G; Sapozhnikov, M G; Shabratova, G S; Skachkova, A N; Skachkov, N B; Strokovsky, E A; Suleimanov, M K; Teshev, R Sh; Tokmenin, V V; Uzhinsky, V V; Vodopyanov, A S; Zaporozhets, S A; Zhuravlev, N I; Zorin, A G; Branford, D; Glazier, D; Watts, D; Woods, P; Britting, A; Eyrich, W; Lehmann, A; Uhlig, F; Dobbs, S; Metreveli, Z; Seth, K; Tann, B; Tomaradze, A; Bettoni, D; Carassiti, V; Dalpiaz, P; Drago, A; Fioravanti, E; Garzia, I; Negrini, M; Savriè, M; Stancari, G; Dulach, B; Gianotti, P; Guaraldo, C; Lucherini, V; Pace, E; Bersani, A; Macri, M; Marinelli, M; Parodi, R F; Dormenev, V; Drexler, P; Düren, M; Eisner, T; Foehl, K; Hayrapetyan, A; Koch, P; Krïoch, B; Kühn, W; Lange, S; Liang, Y; Liu, M; Merle, O; Metag, V; Moritz, M; Nanova, M; Novotny, R; Spruck, B; Stenzel, H; Strackbein, C; Thiel, M; Wang, Q; Clarkson, T; Euan, C; Hill, G; Hoek, M; Ireland, D; Kaiser, R; Keri, T; Lehmann, I; Livingston, K; Lumsden, P; MacGregor, D; McKinnon, B; Montgomery, R; Murray, M; Protopopescu, D; Rosner, G; Seitz, B; Yang, G; Babai, M; Biegun, A K; Glazenborg-Kluttig, A; Guliyev, E; Jothi, V S; Kavatsyuk, M; Lemmens, P; Löhner, H; Messchendorp, J; Poelman, T; Smit, H; van der Weele, J C; Sohlbach, H; Büscher, M; Dosdall, R; Dzhygadlo, R; Esch, S; Gillitzer, A; Goldenbaum, F; Grunwald, D; Jha, V; Kemmerling, G; Kleines, H; Lehrach, A; Maier, R; Mertens, M; Ohm, H; Pohl, D L; Prasuhn, D; Randriamalala, T; Ritman, J; Roeder, M; Sterzenbach, G; Stockmanns, T; Wintz, P; Wüstner, P; Xu, H; Kisiel, J; Li, S; Li, Z; Sun, Z; Xu, H; Fissum, K; Hansen, K; Isaksson, L; Lundin, M; Schröder, B; Achenbach, P; Denig, A; Distler, M; Fritsch, M; Kangh, D; Karavdina, A; Lauth, W; Michel, M; Espi, M C Mora; Pochodzalla, J; Sanchez, S; Sanchez-Lorente, A; Sfienti, C; Weber, T; Dormenev, V I; Fedorov, A A; Korzhik, M V; Missevitch, O V; Boukharov, A; Malyshev, O; Marishev, I; Semenov, A; Varma, R; Höppner, C; Ketzer, B; Konorov, I; Mann, A; Neubert, S; Paul, S; Vandenbroucke, M; Zhang, Q; Khoukaz, A; Rausmann, T; Täschner, A; Wessels, J; Baldin, E; Kotov, K; Peleganchuk, S; Tikhonov, Yu; Hennino, T; Imre, M; Kunne, R; Galliard, C Le; Normand, J P Le; Marchand, D; Maroni, A; Ong, S; Pouthas, J; Ramstein, B; Rosier, P; Sudol, M; Theneau, C; Tomasi-Gustafsson, E; Van de Wiele, J; Zerguerras, T; Boca, G; Braghieri, A; Costanza, S; Fontana, A; Genova, P; Lavezzi, L; Montagna, P; Rotondi, A; Buda, V; Abramov, V V; Davidenko, A M; Derevschikov, A A; Goncharenko, Y M; Grishin, V N; Kachanov, V A; Konstantinov, D A; Kormilitsin, V A; Matulenko, Y A; Melnik, Y M; Meschanin, A P; Minaev, N G; Mochalov, V V; Morozov, D A; Nogach, L V; Nurushev, S B; Ryazantsev, A V; Semenov, P A; Soloviev, L F; Uzunian, A V; Vasiliev, A N; Yakutin, A E; Belostotski, S; Gavrilov, G; Itzotov, A; Kisselev, A; Kravchenko, P; Manaenkov, S; Miklukho, O; Naryshkin, Y; Veretennikov, D; Vikhrov, V; Zhadanov, A; Bäck, T; Cederwall, B; Bargholtz, C; Gerén, L; Tegnér, P E; Thørngren, P; von Würtemberg, K M; Fava, L; Alberto, D; Amoroso, A; Bussa, M P; Busso, L; De Mori, F; Destefanis, M; Ferrero, L; Greco, M; Kugathasan, T; Maggiora, M; Marcello, S; Sosio, S; Spataro, S; Calvo, D; Coli, S; De Remigis, P; Filippi, A; Giraudo, G; Lusso, S; Mazza, G; Mignone, M; Rivetti, A; Wheadon, R; Zotti, L; Morra, O; Iazzi, F; Lavagno, A; Quarati, P; Szymanska, K; Birsa, R; Bradamante, F; Bressan, A; Martin, A; Clement, H; Galnander, B; Calén, H; Fransson, K; Johansson, T; Kupsc, A; Marciniewski, P; Thomé, E; Wolke, M; Zlomanczuk, J; Díaz, J; Ortiz, A; Buda, P; Dmowski, K; Korzeniewski, R; Przemyslaw, D; Slowinski, B; Borsuk, S; Chlopik, A; Guzik, Z; Kopec, J; Kozlowski, T; Melnychuk, D; Plominski, M; Szewinski, J; Traczyk, K; Zwieglinski, B; Bühler, P; Gruber, A; Kienle, P; Marton, J; Widmann, E; Zmeskal, J
2012-01-01
This document illustrates the technical layout and the expected performance of the Micro Vertex Detector (MVD) of the PANDA experiment. The MVD will detect charged particles as close as possible to the interaction zone. Design criteria and the optimisation process as well as the technical solutions chosen are discussed and the results of this process are subjected to extensive Monte Carlo physics studies. The route towards realisation of the detector is outlined.
Exceptional Vertex Operator Algebras and the Virasoro Algebra
Tuite, Michael P.
2008-01-01
We consider exceptional vertex operator algebras for which particular Casimir vectors constructed from the primary vectors of lowest conformal weight are Virasoro descendants of the vacuum. We discuss constraints on these theories that follow from an analysis of appropriate genus zero and genus one two point correlation functions. We find explicit differential equations for the partition function in the cases where the lowest weight primary vectors form a Lie algebra or a Griess algebra. Exam...
A Measurement of Neutral B Mixing using Di-Lepton Events with the BaBar Detector
Energy Technology Data Exchange (ETDEWEB)
Gunawardane, Naveen [Imperial College, London (United Kingdom)
2000-12-01
This thesis reports on a measurement of the neutral B meson mixing parameter, Δm_{d}, at the BABAR experiment and the work carried out on the electromagnetic calorimeter (EMC) data acquisition (DAQ) system and simulation software.
A covariant representation of the Ball-Chiu vertex
Ahmadiniaz, Naser
2012-01-01
In nonabelian gauge theory the three-gluon vertex function contains important structural information, in particular on infrared divergences, and is also an essential ingredient in the Schwinger-Dyson equations. Much effort has gone into analyzing its general structure, and at the one-loop level also a number of explicit computations have been done, using various approaches. Here we use the string-inspired formalism to unify the calculations of the scalar, spinor and gluon loop contributions to the one-loop vertex, leading to an extremely compact representation in all cases. The vertex is computed fully off-shell and in dimensionally continued form, so that it can be used as a building block for higher-loop calculations. We find that the Bern-Kosower loop replacement rules, originally derived for the on-shell case, hold off-shell as well. We explain the relation of the structure of this representation to the low-energy effective action, and establish the precise connection with the standard Ball-Chiu decomposi...
Colour-independent partition functions in coloured vertex models
Energy Technology Data Exchange (ETDEWEB)
Foda, O., E-mail: omar.foda@unimelb.edu.au [Dept. of Mathematics and Statistics, University of Melbourne, Parkville, VIC 3010 (Australia); Wheeler, M., E-mail: mwheeler@lpthe.jussieu.fr [Laboratoire de Physique Théorique et Hautes Energies, CNRS UMR 7589 (France); Université Pierre et Marie Curie – Paris 6, 4 place Jussieu, 75252 Paris cedex 05 (France)
2013-06-11
We study lattice configurations related to S{sub n}, the scalar product of an off-shell state and an on-shell state in rational A{sub n} integrable vertex models, n∈{1,2}. The lattice lines are colourless and oriented. The state variables are n conserved colours that flow along the line orientations, but do not necessarily cover every bond in the lattice. Choosing boundary conditions such that the positions where the colours flow into the lattice are fixed, and where they flow out are summed over, we show that the partition functions of these configurations, with these boundary conditions, are n-independent. Our results extend to trigonometric A{sub n} models, and to all n. This n-independence explains, in vertex-model terms, results from recent studies of S{sub 2} (Caetano and Vieira, 2012, [1], Wheeler, (arXiv:1204.2089), [2]). Namely, 1.S{sub 2}, which depends on two sets of Bethe roots, {b_1} and {b_2}, and cannot (as far as we know) be expressed in single determinant form, degenerates in the limit {b_1}→∞, and/or {b_2}→∞, into a product of determinants, 2. Each of the latter determinants is an A{sub 1} vertex-model partition function.
Light-cone structure of vertex functions for composite fields
Ciafaloni, Marcello
1973-01-01
Vertex functions for composite fields are defined in a model field theory both on and off mass shell. Light-cone dominance at large momentum transfer is shown to hold, by the compositeness assumption, for the off-shell vertex function. On the other hand, it is in general untrue that the elastic form factor probes light-like distances between the constituents inside the nucleon. The relevant light-cone singularity (in the relative space-time separation x) is less important in this case than the large x/sub 0/ behaviour of the wave function at fixed x/sup 2/. It is found however that, under some conditions, the light-cone singularity determines the large x/sub 0/ behaviour of the wave function, and therefore the large q/sup 2/ behaviour of the form factor. A relation similar to that of Drell-Yan- West is finally established between the asymptotic behaviour of the elastic form factor and the threshold behaviour of the absorptive part of the vertex scaling function. (21 refs).
Colour-independent partition functions in coloured vertex models
International Nuclear Information System (INIS)
We study lattice configurations related to Sn, the scalar product of an off-shell state and an on-shell state in rational An integrable vertex models, n∈{1,2}. The lattice lines are colourless and oriented. The state variables are n conserved colours that flow along the line orientations, but do not necessarily cover every bond in the lattice. Choosing boundary conditions such that the positions where the colours flow into the lattice are fixed, and where they flow out are summed over, we show that the partition functions of these configurations, with these boundary conditions, are n-independent. Our results extend to trigonometric An models, and to all n. This n-independence explains, in vertex-model terms, results from recent studies of S2 (Caetano and Vieira, 2012, [1], Wheeler, (arXiv:1204.2089), [2]). Namely, 1.S2, which depends on two sets of Bethe roots, {b1} and {b2}, and cannot (as far as we know) be expressed in single determinant form, degenerates in the limit {b1}→∞, and/or {b2}→∞, into a product of determinants, 2. Each of the latter determinants is an A1 vertex-model partition function
Organization mechanism and counting algorithm on vertex-cover solutions
Wei, Wei; Zhang, Renquan; Niu, Baolong; Guo, Binghui; Zheng, Zhiming
2015-04-01
Counting the solution number of combinational optimization problems is an important topic in the study of computational complexity, which is concerned with Vertex-Cover in this paper. First, we investigate organizations of Vertex-Cover solution spaces by the underlying connectivity of unfrozen vertices and provide facts on the global and local environment. Then, a Vertex-Cover Solution Number Counting Algorithm is proposed and its complexity analysis is provided, the results of which fit very well with the simulations and have a better performance than those by 1-RSB in the neighborhood of c = e for random graphs. Based on the algorithm, variation and fluctuation on the solution number the statistics are studied to reveal the evolution mechanism of the solution numbers. Furthermore, the marginal probability distributions on the solution space are investigated on both the random graph and scale-free graph to illustrate the different evolution characteristics of their solution spaces. Thus, doing solution number counting based on the graph expression of the solution space should be an alternative and meaningful way to study the hardness of NP-complete and #P-complete problems and the appropriate algorithm design can help to achieve better approximations of solving combinational optimization problems and the corresponding counting problems.
On the Verge of One Petabyte - the Story Behind the BaBar Database System
International Nuclear Information System (INIS)
The BaBar database has pioneered the use of a commercial ODBMS within the HEP community. The unique object-oriented architecture of Objectivity/DB has made it possible to manage over 700 terabytes of production data generated since May'99, making the BaBar database the world's largest known database. The ongoing development includes new features, addressing the ever-increasing luminosity of the detector as well as other changing physics requirements. Significant efforts are focused on reducing space requirements and operational costs. The paper discusses our experience with developing a large scale database system, emphasizing universal aspects which may be applied to any large scale system, independently of underlying technology used
An application framework and data model prototype for the BaBar experiment
International Nuclear Information System (INIS)
The BaBar experiment is under construction, and will do physics with e+e- colliding beams in the 10 GeV center-of-mass energy region at the PEP-II accelerator at the Stanford Linear Accelerator Center. This experiment is expected to accumulate of order 109 events per calendar year, with first data in 1999. The data be stored efficiently, and must be easily accessible for multiple and frequent physics analyses. The application framework must accommodate a variety of analysis modules and multiple input/output streams. The BaBar collaboration has developed a prototype for the application framework and data access, written in C++ using an object-oriented design philosophy. (author)
The Event Browser：An Intutive Approach to Browsing BaBar Object Databases
Institute of Scientific and Technical Information of China (English)
AdeyemiAdesanya
2001-01-01
Providing efficient access to more than 300TB of experiment data is the responsibility of the BaBar1 Databases Group.Unlike generic tools,The Event Browser presents users with an abstraction of the BaBar data model.Multithreaded CORBA2 servers perform database operations using small transactions in an effort to avoid lock contention issues and provide adequate response times.The GUI client is implemented in Java and can be easily deployed throughout the community in the form of a web applet.The browser allows users to examine collections of related physics events and identify associations between the collections and the physical files in which they reside,helping administrators distribute data to other sites worldwide,This paper discusses the various aspects of the Event Browser including requirements,design challenges and key features of the current implementation.
Event Logging and Distribution for the BaBar Online System
International Nuclear Information System (INIS)
We discuss the BABAR experiment software and computing infrastructure used for event logging and distribution to prompt reconstruction system. The raw data for typical BABAR events is about 30-50 kB per event. During the data taking a 100 Hz stream of events is collected from a farm of 32 online computers amounting to about 3-5 MB/s. A robust and efficient multi-threaded, TCP/IP based logging manager software was written to serve this purpose. Monitoring of the status of the program is achieved using CORBA. The same program is also used to distribute the logged events to a larger farm of 200 unix processors to process data promptly. This prompt processing involves full reconstruction and calibration programs before final storage in the Objectivity database. We describe the performance of underlying hardware and software, and address scalability of the program
Aspects of CP violation with the BABAR detector. Constraints on the CKM Matrix
International Nuclear Information System (INIS)
This document presents the work done within the BABAR Collaboration as well as a phenomenological study on the interpretation of the B measurements related to the Unitarity Triangle. The read-out electronics of the Cerenkov detector, the DIRC, and especially the Time-Digital-Converter designed at LPNHE are described. Two major results of the BABAR Collaboration are presented: the measurement of the sin(2β) parameter in the b → ccs modes, which has established the CP violation in the B sector in 2001 and the study of CP asymmetries in the B0 → π+π- channel. The constraints on the Unitarity Triangle from the K0K0 system, the B semi-leptonic decays, the B oscillation parameters are in excellent agreement with those from sin(2β) and α. (author)
Energy Technology Data Exchange (ETDEWEB)
Barnes, Christopher P
2005-03-01
The D0 detector underwent a major upgrade to maximize its ability to fully exploit Run II at the Fermilab Tevatron, the world's highest energy collider. The upgrade included a completely new central tracking system with an outer scintillating fiber tracker and an inner silicon vertex detector all within a 2T superconducting solenoid. This thesis describes the development of high level trigger algorithms including vertexing, impact parameter significance and invariant mass, that utilize tracks from these detectors. One of the main physics goals of Run II is the observation of B{sub s} oscillations. This measurement, which cannot be performed at the B factories, will significantly constrain the ''unitarity triangle'' associated with Cp violation and so probe the Standard Model of particle physics. Furthermore this is an interesting measurement as the study of mixing in meson systems has a long history for revealing new physics. The second part of this thesis presents a study of the hadronic decay B{sub s} {yields} D{sub s}{pi}. This important mode provides the best proper time resolution for B{sub s} mixing and is reconstructed for the first time at D0. Projections on the sensitivity to B{sub s} oscillations are then presented.
International Nuclear Information System (INIS)
The D0 detector underwent a major upgrade to maximize its ability to fully exploit Run II at the Fermilab Tevatron, the world's highest energy collider. The upgrade included a completely new central tracking system with an outer scintillating fiber tracker and an inner silicon vertex detector all within a 2T super conducting solenoid. This thesis describes the development of high level trigger algorithms including vertexing, impact parameter significance and invariant mass, that utilize tracks from these detectors. One of the main physics goals of Run II is the observation of Bs oscillations. This measurement, which cannot be performed at the B factories, will significantly constrain the ''unitarity triangle'' associated with CP violation and so probe the Standard Model of particle physics. Furthermore this is an interesting measurement as the study of mixing in meson systems has a long history for revealing new physics. The second part of this thesis presents a study of the hadronic decay Bs → Dsπ. This important mode provides the best proper time resolution for Bs mixing and is reconstructed for the first time at D0. Projections on the sensitivity to Bs oscillations are then presented
Distributing File—based Data to Remote sites within the BABAR Collaboration
Institute of Scientific and Technical Information of China (English)
TimAdye; AlviseDorigo; 等
2001-01-01
BABAR[1] uses two formats for its data:Objectivity database and ROOT[1] files.This poster concerns the distribution of the latter-for Objectivity data see [3].The BABAR analysis data is stored in ROOT files-one per physics run and analysis selection channel-maintained in a large directory tree,Currently BABAR has more than 4.5 TBytes in 200,000 ROOT files.This data is (mostly)produced at SLAC,but is required for analysis at universities and research centres throughout the US and Europe.Two basic problems confront us when we seek to import bulk data from SLAC to an institute's local storage via the network.We must determine which files must be imported (depending on the local site requirements and which files have already been imported),and we must make the optimum use of the network when transferring the data,Basic ftp-like tools(ftp,scp,etc)do not attempt to solve the first problem.More sophisticated tools like rsync[4],the widely-used mirror/synchronisation program,compare local and remote file systems,checking for changes(based on file date,size and,if desired,an elaborate checksum)in order to only copy new or modified files,However rsync allows for only limited file selection.Also when,as in BABAR,an extremely large directory structure must be scanned,rsync can take several hours just to determine which files need to be copied.Although rsync(and scp)provides on -the=fly compression,it does not allow us to optimise the network transfer by using multiple streams,abjusting the TCP window size or separating encrypted authentication from unencrypted data channels.
Energy Technology Data Exchange (ETDEWEB)
Brown, David Norvil [University of Louisville
2013-07-25
The University of Louisville High Energy Physics group has undertaken a long-term effort in understanding baryon production in elementary particle processes in the 10 GeV energy region. We have contributed significantly to the broad program of the BaBar Collaboration, particularly in support of computing, data visualization, and simulation. We report here on progress in the areas of service to the Collaboration and understanding of baryon production via measurement of inclusive hadronic particle spectra.
A Measurement of the Exclusive Branching Fraction for B → π K at BaBar
Energy Technology Data Exchange (ETDEWEB)
Aspinwall, Marie Louise [Imperial College, London (United Kingdom)
2002-02-01
This thesis presents an exclusive measurement of the branching fraction B for the rare charmless hadronic B decays to πK final states. A sample of 22.57±0.36 million BB pairs was collected with the BaBar detector at the Stanford Linear Accelerator Center's PEP-II B Factory, during the Run 1 data taking period (1999-2000).
The RPC-based IFR system at BaBar experiment preliminary results
Piccolo, D; Bagnasco, S; Baldini, R; Band, H R; Bionta, R; Buzzo, A; Calcaterra, A; Cavallo, N; Contri, R; Crosetti, G; De Nardo, Gallieno; De Sangro, R; Fabozzi, F; Falciai, D; Finocchiaro, G; Gatto, C; Johnson, J; Lista, L; Lo Vetere, M; Macri, M; Monge, R; Palano, A; Paolucci, P; Passaggio, S; Patrignani, C; Patteri, P; Peruzzi, I; Piccolo, M; Robutti, E; Santroni, A; Sciacca, C; Wright, D; Yu, Z; Zallo, A
2002-01-01
The IFR system is a RPC-based detector used to identify muons and neutral hadrons in the BaBar experiment at PEP II machine in SLAC. The RPC system can be used to reconstruct the trajectory of muons, pions and neutral hadrons interacting in the iron of the IFR. The different range and hit pattern allow to discriminate different particles crossing the IFR. An overview of the system design and the preliminary results on the IFR performances are reported.
Applying object-oriented software engineering at the BaBar collaboration
International Nuclear Information System (INIS)
The BaBar experiment at SLAC will start taking data in 1999. We are attempting to build its reconstruction software using good software engineering practices, including the use of object-oriented technology. We summarize our experience to date with analysis and design activities, training, CASE and documentation tools, C++ programming practice and similar topics. The emphasis is on the practical issues of simultaneously introducing new techniques to a large collaboration while under a deadline for system delivery. (orig.)
Applying object-oriented software engineering at the BaBar collaboration
Energy Technology Data Exchange (ETDEWEB)
Jacobsen, B. [California Univ., Berkeley (United States). Dept. of Physics; BABAR Collaboration
1997-04-11
The BaBar experiment at SLAC will start taking data in 1999. We are attempting to build its reconstruction software using good software engineering practices, including the use of object-oriented technology. We summarize our experience to date with analysis and design activities, training, CASE and documentation tools, C++ programming practice and similar topics. The emphasis is on the practical issues of simultaneously introducing new techniques to a large collaboration while under a deadline for system delivery. (orig.).
Measurements of the Collins asymmetries for kaons and pions in e+e- annihilations at BABAR
Filippi, A.
2016-07-01
New measurements of the Collins asymmetries were performed by BABAR exploiting inclusive e+e- → h1h2 X annihilations (with h1,2 = π and/or K) mainly at the energy of the ϒ(4S), which corresponds to a squared transferred momentum Q2 ~ 110 GeV2c4. For the first time asymmetries following strange quarks fragmentation could be derived as a function of the fractional energy carried out by inclusively emitted hadron pairs.
A readout system for the micro-vertex-detector demonstrator for the CBM experiment at FAIR
Energy Technology Data Exchange (ETDEWEB)
Schrader, Christoph
2011-06-09
The Compressed Baryonic Matter Experiment (CBM) is a fixed target heavy ion experiment currently in preparation at the future FAIR accelerator complex in Darmstadt. The CBM experiment focuses on the measurements of diagnostic probes of the early and dense phase of the fireball at beam energies from 8 up to 45 AGeV. As observables, rare hadronic, leptonic and photonic probes are used, including open charm. Open charm will be identified by reconstructing the secondary decay vertex of the corresponding short lived particles. As the central component for track reconstruction, a detector system based on silicon semiconductor detectors is planned. The first three stations of the Silicon Tracking System (STS) make up the so-called Micro-Vertex-Detector (MVD) operating in moderate vacuum. Because of the well-balanced compromise between an excellent spatial resolution (few {mu}m), low material budget ({proportional_to}50 {mu}m Si), adequate radiation tolerance and readout speed, Monolithic Active Pixel Sensors (MAPS) based on CMOS technology are more suited than any other technology for the reconstruction of the secondary vertex in CBM. A new detector concept has to be developed. Two MVD-Demonstrator modules have been successfully tested with 120 GeV pions at the CERN-SPS. The main topic of this thesis is the development of a control and readout concept of several MVD-Demonstrator modules with a common data acquisition system. In order to achieve the required results a front-end electronics device has been developed which is capable of reading the analogue signals of two sensors on a ex-print cable. The high data rate of the MAPS sensors (1.2 Gbit per second and sensor by 50 MHz and 12 bit ADC resolution) requires a readout system which processes the data on-line in a pipeline to avoid dead times. In order to implement the pipeline processing an FPGA is used, which is located on an additional hardware platform. In order to integrate the MVD-Demonstrator readout board in the
A readout system for the micro-vertex-detector demonstrator for the CBM experiment at FAIR
International Nuclear Information System (INIS)
The Compressed Baryonic Matter Experiment (CBM) is a fixed target heavy ion experiment currently in preparation at the future FAIR accelerator complex in Darmstadt. The CBM experiment focuses on the measurements of diagnostic probes of the early and dense phase of the fireball at beam energies from 8 up to 45 AGeV. As observables, rare hadronic, leptonic and photonic probes are used, including open charm. Open charm will be identified by reconstructing the secondary decay vertex of the corresponding short lived particles. As the central component for track reconstruction, a detector system based on silicon semiconductor detectors is planned. The first three stations of the Silicon Tracking System (STS) make up the so-called Micro-Vertex-Detector (MVD) operating in moderate vacuum. Because of the well-balanced compromise between an excellent spatial resolution (few μm), low material budget (∝50 μm Si), adequate radiation tolerance and readout speed, Monolithic Active Pixel Sensors (MAPS) based on CMOS technology are more suited than any other technology for the reconstruction of the secondary vertex in CBM. A new detector concept has to be developed. Two MVD-Demonstrator modules have been successfully tested with 120 GeV pions at the CERN-SPS. The main topic of this thesis is the development of a control and readout concept of several MVD-Demonstrator modules with a common data acquisition system. In order to achieve the required results a front-end electronics device has been developed which is capable of reading the analogue signals of two sensors on a ex-print cable. The high data rate of the MAPS sensors (1.2 Gbit per second and sensor by 50 MHz and 12 bit ADC resolution) requires a readout system which processes the data on-line in a pipeline to avoid dead times. In order to implement the pipeline processing an FPGA is used, which is located on an additional hardware platform. In order to integrate the MVD-Demonstrator readout board in the HADES data
Events simulation production for the BaBar experiment using the grid approach content
International Nuclear Information System (INIS)
The BaBar experiment is taking data since 1999, investigating the violation of charge and parity (CP) symmetry in the field of High Energy Physics. Event simulation is an intensive computing task, due to the complexity of algorithm based on Monte-Carlo method implemented using the GEANT engine. Data needed as input for the simulation, stored in the ROOT format, are classified into two categories: conditions data for describing the detector status when data are recorded, and background triggers data for including noise signal necessary to obtain a realistic simulation. In order to satisfy these requirements, in the traditional BaBar computing model events are distributed over several sites involved in the collaboration where each site manager centrally manages a private farm dedicated to simulation production. The new grid approach applied to the BaBar production framework is discussed along with the schema adopted for data deployment via Xrootd servers, including data management using grid middle ware on distributed storage facilities spread over the INFN-GRID network. A comparison between the two models is provided, describing also the custom application developed for performing the whole production task on the grid and showing results achieved. (Author)
The IFR Online Detector Control system at the BaBar Experiment
International Nuclear Information System (INIS)
The Instrumented Flux Return (IFR)[1] is one of the five subdetectors of the BaBar[2] experiment on the PEP II accelerator at SLAC. The IFR consists of 774 Resistive Plate Chamber (RPC) detectors, covering an area of about 2,000 m2 and equipped with 3,000 Front-end Electronic Cards (FEC) reading about 50,000 channels (readout strips). The first aim of a B-factory experiment is to run continuously without any interruption and then the Detector Control system plays a very important role in order to reduce the dead-time due to the hardware problems. The I.N.F.N. group of Naples has designed and built the IFR Online Detector Control System (IODC)[3] in order to control and monitor the operation of this large number of detectors and of all the IFR subsystems: High Voltage, Low Voltage, Gas system, Trigger and DAQ crates. The IODC consists of 8 custom DAQ stations, placed around the detector and one central DAQ station based on VME technology and placed in electronic house. The IODC use VxWorks and EPICS to implement slow control data flow of about 2500 hardware channels and to develop part of the readout module consisting in about 3500 records. EPICS is interfaced with the BaBar Run Control through the Component Proxy and with the BaBar database (Objectivity) through the Archiver and KeyLookup processes
Choosing CPUs in an Open Market: System Performance Testing for the BaBar Online Farm
International Nuclear Information System (INIS)
BABAR is a high-rate experiment to study CP violation in asymmetric e+e- collisions. The BABAR Online Farm is a pool of workstations responsible for the last layer of event selection, as well as for full reconstruction of selected events and for monitoring functions. A large number of machine architectures were evaluated for use in this Online Farm. We present an overview of the results of this evaluation, which include tests of low-level OS primitives, tests of memory architecture, and tests of application-specific CPU performance. Factors of general interest to others making hardware decisions are highlighted. Performance of current BABAR reconstruction (written in C++) is found to scale fairly well with SPECint95, but with some noticeable deviations. Even for machines with similar SPEC CPU ratings, large variations in memory system performance exist. No single operating system has an overall edge in the performance of its primitives. In particular, freeware operating systems perform no worse overall than the commercial offerings
An application framework and data model prototype for the BaBar experiment
Quarrie, D
2003-01-01
The BaBar experiment is a high energy physics experiment to do physics with e sup + e sup - colliding beams in the 10 GeV center-of-mass energy at the PEP-II accelerator at the Stanford Linear Accelerator Center. The principal objectives are to study CP violation and rare processes in decays of B mesons. The experiment is under construction, with first data anticipated in 1999. The BaBar experiment is expected to accumulate of order 10 sup 9 events per calendar year, with over 10 sup 8 interesting hadronic events. The data must be stored efficiently, but must be easily accessible in order for multiple and frequent physics analyses to be carried out. The analysis framework must be flexible enough to accommodate a variety of analysis modules and multiple input/output streams. The BaBar collaboration has developed a prototype for the analysis framework and data access, written in C++ using an object-oriented design philosophy. The data access is based on the Farfalla package. The base class is a ''node''. Variou...
Energy Technology Data Exchange (ETDEWEB)
Grenier, Philippe
2006-04-15
This document is organized into 4 parts. The first part is dedicated to the Babar experiment that is installed on the e{sup +}e{sup -} collider at Stanford linear accelerator center. The formalism of the standard model and the CP violation in the B meson system are first introduced, then the Babar experiment is described and its main results are recalled: sin(2{beta}) 0.722 {+-} 0.040 {+-} 0.023; {alpha} = (103 + 11 - 9) degrees; {gamma} = (52 + 23 - 18) degrees. The author highlights 2 issues in which he was involved: the detector background noise induced by the machine and the beam injection system. The second part deals with DIRC (detector of internally reflected Cherenkov light) that is used for particle identification. The phenomenology of hadron decay of B mesons is described in the third part, the hypothesis of the factorization approximation is challenged. The last part is dedicated to experimental results concerning the measurement of branching ratios, the search for suppressed modes and the determination of decay amplitudes.
Full fermion-boson vertex function derived in terms of symmetry relations in Abelian gause theory
Institute of Scientific and Technical Information of China (English)
HE HanXin
2008-01-01
Nonperturbative studies such as confinement and dynamical chiral symmetry breaking need the nonperturbative interacting vertex functions. In this paper, an approach to determining the full fermion-boson vertex function in four-dimensional Abelian gauge theory is presented: this full vertex function is derived in terms of a set of normal (longitudinal) and transverse Ward-Takahashi relations for the fer-mion-boson (vector) and axial-vector vertices in the momentum space in the case of massless fermion. Such a derived fermion-boson vertex function should be sat-isfied both perturbatively and nonperturbatively. The fact that such a derived full fermion-boson vertex function to one-loop order holds indeed is proven and the nonperturbative form of this vertex is also under discussion.
Performance of the reconstruction algorithms of the FIRST experiment pixel sensors vertex detector
Energy Technology Data Exchange (ETDEWEB)
Rescigno, R., E-mail: regina.rescigno@iphc.cnrs.fr [Institut Pluridisciplinaire Hubert Curien, 23 rue du Loess, 67037 Strasbourg Cedex 2 (France); Finck, Ch.; Juliani, D. [Institut Pluridisciplinaire Hubert Curien, 23 rue du Loess, 67037 Strasbourg Cedex 2 (France); Spiriti, E. [Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali di Frascati (Italy); Istituto Nazionale di Fisica Nucleare - Sezione di Roma 3 (Italy); Baudot, J. [Institut Pluridisciplinaire Hubert Curien, 23 rue du Loess, 67037 Strasbourg Cedex 2 (France); Abou-Haidar, Z. [CNA, Sevilla (Spain); Agodi, C. [Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud (Italy); Alvarez, M.A.G. [CNA, Sevilla (Spain); Aumann, T. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); Battistoni, G. [Istituto Nazionale di Fisica Nucleare - Sezione di Milano (Italy); Bocci, A. [CNA, Sevilla (Spain); Böhlen, T.T. [European Organization for Nuclear Research CERN, Geneva (Switzerland); Medical Radiation Physics, Karolinska Institutet and Stockholm University, Stockholm (Sweden); Boudard, A. [CEA-Saclay, IRFU/SPhN, Gif sur Yvette Cedex (France); Brunetti, A.; Carpinelli, M. [Istituto Nazionale di Fisica Nucleare - Sezione di Cagliari (Italy); Università di Sassari (Italy); Cirrone, G.A.P. [Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud (Italy); Cortes-Giraldo, M.A. [Departamento de Fisica Atomica, Molecular y Nuclear, University of Sevilla, 41080-Sevilla (Spain); Cuttone, G.; De Napoli, M. [Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud (Italy); Durante, M. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); and others
2014-12-11
Hadrontherapy treatments use charged particles (e.g. protons and carbon ions) to treat tumors. During a therapeutic treatment with carbon ions, the beam undergoes nuclear fragmentation processes giving rise to significant yields of secondary charged particles. An accurate prediction of these production rates is necessary to estimate precisely the dose deposited into the tumours and the surrounding healthy tissues. Nowadays, a limited set of double differential carbon fragmentation cross-section is available. Experimental data are necessary to benchmark Monte Carlo simulations for their use in hadrontherapy. The purpose of the FIRST experiment is to study nuclear fragmentation processes of ions with kinetic energy in the range from 100 to 1000 MeV/u. Tracks are reconstructed using information from a pixel silicon detector based on the CMOS technology. The performances achieved using this device for hadrontherapy purpose are discussed. For each reconstruction step (clustering, tracking and vertexing), different methods are implemented. The algorithm performances and the accuracy on reconstructed observables are evaluated on the basis of simulated and experimental data.
Track and vertex reconstruction on GPUs for the Mu3e experiment
International Nuclear Information System (INIS)
The Mu3e experiment searches for the lepton flavour violating decay μ → eee, aiming at a branching ratio sensitivity better than 10-16. To reach this sensitivity, muon rates above 109 μ/s are required. A high precision silicon pixel tracking detector combined with excellent timing resolution from scintillating fibers and tiles will measure the momenta, vertices and timing of the decay products of muons stopped in the target to suppress background. The trigger-less readout system will deliver about 100 GB/s of zero-suppressed data. A network of optical links and switching FPGAs sends the complete detector data for a time slice to one node of the filter farm. An FPGA inside the filter farm PC transfers the event data to the GPU via PCIe direct memory access. The GPU finds and fits tracks using a 3D tracking algorithm for multiple scattering dominated resolution. In a second step, a three track vertex fit is performed, allowing for a reduction of the output data rate to below 100 MB/s by removing combinatorial background. The talk discusses the implementation of the fits on the GPU, which processes 1010 combinations of hits from three layers per second.
LHCb Vertex Locator: Performance and radiation damage in LHC Run 1 and preparation for Run 2
Szumlak, T.; Obła˛kowska-Mucha, A.
2016-07-01
LHCb is a dedicated experiment to study New Physics in the decays of heavy hadrons at the Large Hadron Collider (LHC) at CERN. Heavy hadrons are identified through their flight distance in the Vertex Locator (VELO). The VELO comprises 42 modules made of two n+-on-n 300 μm thick half-disc silicon sensors with R- and Φ-measuring micro-strips. In order to allow retracting the detector, the VELO is installed as two movable halves containing 21 modules each. The detectors are operated in a secondary vacuum and are cooled by a bi-phase CO2 cooling system. During data taking in LHC Run 1 the LHCb VELO has operated with an extremely high efficiency and excellent performance. The track finding efficiency is typically greater than 98%. An impact parameter resolution of less than 35 μm is achieved for particles with transverse momentum greater than 1 GeV/c. An overview of all important performance parameters will be given. The VELO sensors have received a large and non-uniform radiation dose of up to 1.2 ×1014 1 MeV neutron equivalent cm-2 during the first LHC run. Silicon type-inversion has been observed in regions close to the interaction point. The preparations for LHC Run 2 are well under way and the VELO has already recorded tracks from injection line tests. The current status and plans for new operational procedures addressing the non-uniform radiation damage are shortly discussed.
On integral forms for vertex algebras associated with affine Lie algebras and lattices
McRae, Robert
2014-01-01
We revisit the construction of integral forms for vertex (operator) algebras $V_L$ based on even lattices $L$ using generators instead of bases, and we construct integral forms for $V_L$-modules. We construct integral forms for vertex (operator) algebras based on highest-weight modules for affine Lie algebras and we exhibit natural generating sets. For vertex operator algebras in general, we give conditions showing when an integral form contains the standard conformal vector generating the Vi...
Restrictions on the four vector boson vertex in a weakly interacting standard model
International Nuclear Information System (INIS)
There is no experimental evidence that the four vector boson (4W) vertex predicted by the standard model exists. To study the effects of this vertex, we introduce the parameter κ such that κg2 is the new 4W coupling constant. We set constraints on κ by considering unitarity requirements for vector boson scattering amplitudes. We find that the 4W vertex must exist if the vector bosons interact weakly up to √s≅300-350 GeV. (orig.)
Higher genus characters for vertex operator superalgebras on sewn Riemann surfaces
Alexander Zuevsky
2013-01-01
We review our recent results on computation of the higher genus characters for vertex operator superalgebras modules. The vertex operator formal parameters are associated to local parameters on Riemann surfaces formed in one of two schemes of (self- or tori- ) sewing of lower genus Riemann surfaces. For the free fermion vertex operator superalgebra we present a closed formula for the genus two continuous orbifold partition functions (in either sewings) in terms of an in...
Algorithms to find vertex-to-clique Center in a Graph using BC-representation
Directory of Open Access Journals (Sweden)
A. Ashok Kumar
2013-05-01
Full Text Available In this paper, we introduce algorithms to find the vertex-to-clique (or (V, ζ -distance d(v, C between a vertex v and a clique C in a graph G, (V, ζ -eccentricity e1 (v of a vertex v, and (V, ζ -center Z1(G of a graph G usingBC - representation. Moreover, the algorithms are proved for their correctness and analyzed for their time complexity.
Primary vertex reconstruction based on the Kalman filter technique at BESIII
International Nuclear Information System (INIS)
Primary vertex reconstruction is crucial to estimate the beam profile in collision experiments. We study the principle of an iterative process, called the Kalman filter method, and apply it to primary vertex reconstruction at BESIII. A Newton procedure to find the zero point of the distance function's gradient is used for primary vertex finding in 3-dimensional space. Results are obtained based on raw data at BESIII. (authors)
Studies of vertex tracking with SOI pixel sensors for future lepton colliders
Battaglia, Marco; Contarato, Devis; Denes, Peter; Liko, Dietrich; Mattiazzo, Serena; Pantano, Devis
2012-07-01
This paper presents a study of vertex tracking with a beam hodoscope consisting of three layers of monolithic pixel sensors in SOI technology on high-resistivity substrate. We study the track extrapolation accuracy, two-track separation and vertex reconstruction accuracy in π- Cu interactions with 150 and 300 GeV/c pions at the CERN SPS. Results are discussed in the context of vertex tracking at future lepton colliders.
Studies of Vertex Tracking with SOI Pixel Sensors for Future Lepton Colliders
Battaglia, Marco; Denes, Peter; Liko, Dietrich; Mattiazzo, Serena; Pantano, Devis
2012-01-01
This paper presents a study of vertex tracking with a beam hodoscope consisting of three layers of monolithic pixel sensors in SOI technology on high-resistivity substrate. We study the track extrapolation accuracy, two-track separation and vertex reconstruction accuracy in pion-Cu interactions with 150 and 300 GeV/c pions at the CERN SPS. Results are discussed in the context of vertex tracking at future lepton colliders.
Transverse Ward-Takahashi Relation for the Vector Vertex in Quantum Field Theory
Institute of Scientific and Technical Information of China (English)
HE Han-Xin
2001-01-01
The transverse Ward-Takahashi (W-T) relation for the vector vertex in quantum field theory is derived by calculating the curl of the time-ordered product of the three-point function including the vector current operator. This provides the constraint on the transverse part of the vertex. By combining the transverse and normal (longitudinal)W-T identities, we obtain the expression for the full vector vertex function.``
The eight-vertex model with quasi-periodic boundary conditions
Niccoli, G.; Terras, V.
2016-01-01
We study the inhomogeneous eight-vertex model (or equivalently the XYZ Heisenberg spin-1/2 chain) with all kinds of integrable quasi-periodic boundary conditions: periodic, {σ }x-twisted, {σ }y-twisted or {σ }z-twisted. We show that in all these cases but the periodic one with an even number of sites {N}, the transfer matrix of the model is related, by the vertex-IRF transformation, to the transfer matrix of the dynamical six-vertex model with antiperiodic boundary conditions, which we have recently solved by means of Sklyanin's separation of variables approach. We show moreover that, in all the twisted cases, the vertex-IRF transformation is bijective. This allows us to completely characterize, from our previous results on the antiperiodic dynamical six-vertex model, the twisted eight-vertex transfer matrix spectrum (proving that it is simple) and eigenstates. We also consider the periodic case for {N} odd. In this case we can define two independent vertex-IRF transformations, both not bijective, and by using them we show that the eight-vertex transfer matrix spectrum is doubly degenerate, and that it can, as well as the corresponding eigenstates, also be completely characterized in terms of the spectrum and eigenstates of the dynamical six-vertex antiperiodic transfer matrix. In all these cases we can adapt to the eight-vertex case the reformulations of the dynamical six-vertex transfer matrix spectrum and eigenstates that had been obtained by T-Q functional equations, where the Q-functions are elliptic polynomials with twist-dependent quasi-periods. Such reformulations enable one to characterize the eight-vertex transfer matrix spectrum by the solutions of some Bethe-type equations, and to rewrite the corresponding eigenstates as the multiple action of some operators on a pseudo-vacuum state, in a similar way as in the algebraic Bethe ansatz framework.
Effects of Vertex Activity and Self-organized Criticality Behavior on a Weighted Evolving Network
International Nuclear Information System (INIS)
Effects of vertex activity have been analyzed on a weighted evolving network. The network is characterized by the probability distribution of vertex strength, each edge weight and evolution of the strength of vertices with different vertex activities. The model exhibits self-organized criticality behavior. The probability distribution of avalanche size for different network sizes is also shown. In addition, there is a power law relation between the size and the duration of an avalanche and the average of avalanche size has been studied for different vertex activities
Design and Implementation of a Procedural Content Generation Web Application for Vertex Shaders
Quiroz, Juan C.; Dascalu, Sergiu M
2016-01-01
We present a web application for the procedural generation of transformations of 3D models. We generate the transformations of the 3D models by algorithmically generating the vertex shaders of the 3D models. The vertex shaders are created with an interactive genetic algorithm, which displays to the user the visual effect caused by each vertex shader, allows the user to select the visual effect the user likes best, and produces a new generation of vertex shaders using the user feedback as the ...
An FPT Algorithm and a Polynomial Kernel for Linear Rankwidth-1 Vertex Deletion
Kanté, Mamadou Moustapha; Kim, Eun Jung; Kwon, O-joung; Paul, Christophe
2015-01-01
Linear rankwidth is a linearized variant of rankwidth, introduced by Oum and Seymour [Approximating clique-width and branch-width. J. Combin. Theory Ser. B, 96(4):514--528, 2006]. Motivated from recent development on graph modification problems regarding classes of graphs of bounded treewidth or pathwidth, we study the Linear Rankwidth-1 Vertex Deletion problem (shortly, LRW1-Vertex Deletion). In the LRW1-Vertex Deletion problem, given an $n$-vertex graph $G$ and a positive integer $k$, we wa...
Effects of Vertex Activity and Self-organized Criticality Behavior on a Weighted Evolving Network
Institute of Scientific and Technical Information of China (English)
ZHANG Gui-Qing; YANG Qiu-Ying; CHEN Tian-Lun
2008-01-01
Effects of vertex activity have been analyzed on a weighted evolving network. The network is characterized by the probability distribution of vertex strength, each edge weight and evolution of the strength of vertices with different vertex activities. The model exhibits self-organized criticality behavior. The probability distribution of avalanche size for different network sizes is also shown. In addition, there is a power law relation between the size and the duration of an avalanche and the average of avalanche size has been studied for different vertex activities.
Applications of vertex algebra covering procedures to Chevalley groups and modular moonshine
Griess Jr., Robert L.; lam, Ching Hung
2013-01-01
A vertex operator algebra of lattice type ADE has a standard integral form which extends a Chevalley basis for its degree 1 Lie algebra. This integral form may be used to define a vertex algebra over a commutative ring $R$ and to get a Chevalley group over $R$ of the same type, acting as automorphisms of this vertex algebra. We define vertex algebras of types BCFG over a commutative ring and certain reduced VAs, then get analogous results about automorphism groups. In characteristics 2 and 3,...
Quarkonium Spectroscopy And Search for New States at BaBar
Energy Technology Data Exchange (ETDEWEB)
Cibinetto, G.
2011-11-04
The BaBar experiment at the PEP-II B-factory gives excellent opportunities for the quarkonium spectroscopy. Investigation of the properties of new states like the X(3872), Y(3940) and Y(4260) are performed aiming to understand their nature. Recent BaBar results will be presented in this paper. At the B-factories charmonium and charmonium-like states are copiously produced via several mechanisms: in B decay (color suppressed b {yields} c transition), double charmonium production (e{sup +}e{sup -} {yields} c{bar c} + c{bar c}), two photons production ({gamma}*{gamma}* {yields} c{bar c}, where the c{bar c} state has positive C-parity) and in initial state radiation (ISR) when the e{sup {+-}} in its initial state emits a photon lowering the effective center of mass energy of the e{sup +}e{sup -} interaction (e{sup +}e{sup -} {yields} {gamma}{sub ISR} + c{bar c}, where the charmonium state has the quantum numbers J{sup PC} = 1{sup -2}). Many new states have been recently discovered at the B-factories, BaBar and Belle, above the D{bar D} threshold in the charmonium energy region. While some of them appear to be consistent with conventional c{sub c} states others do not fit with any expectation. Several interpretations for these states have been proposed: for some of them the mass values suggest that they could be conventional charmonia, but also other interpretations like D{sup 0}{bar D}*{sup 0} molecule or diquark-antidiquark states among many other models have been advanced. Reviews can be found in Refs. [1][2]. In all cases the picture is not completely clear. This situation could be remedied by a coherent search of the decay pattern to D{bar D}, search for production in two-photon fusion and ISR, and of course improving the statistical precision upon the current measurements. The BaBar experiment at the PEP-II asymmetric collider, designed to perform precision measurement of CP violation in the B meson system, has an extensive quarkonium spectroscopy program. Recent
W-symmetry, topological vertex and affine Yangian
Procházka, Tomáš
2015-01-01
We discuss the representation theory of non-linear chiral algebra $\\mathcal{W}_{1+\\infty}$ of Gaberdiel and Gopakumar and its connection to Yangian of $\\hat{\\mathfrak{u}(1)}$ whose presentation was given by Tsymbaliuk. The characters of completely degenerate representations of $\\mathcal{W}_{1+\\infty}$ are for generic values of parameters given by the topological vertex. The Yangian picture provides an infinite number of commuting charges which can be explicitly diagonalized in $\\mathcal{W}_{1+\\infty}$ highest weight representations. Many properties that are difficult to study in $\\mathcal{W}_{1+\\infty}$ picture turn out to have a simple combinatorial interpretation.
New Hybrid Genetic Algorithm for Vertex Cover Problems
Institute of Scientific and Technical Information of China (English)
霍红卫; 许进
2003-01-01
This paper presents a new hybrid genetic algorithm for the vertex cover problems in which scan-repair and local improvement techniques are used for local optimization. With the hybrid approach, genetic algorithms are used to perform global exploration in a population, while neighborhood search methods are used to perform local exploitation around the chromosomes. The experimental results indicate that hybrid genetic algorithms can obtain solutions of excellent quality to the problem instances with different sizes. The pure genetic algorithms are outperformed by the neighborhood search heuristics procedures combined with genetic algorithms.
Edge-injective and edge-surjective vertex labellings
DEFF Research Database (Denmark)
Brandt, Stephan; Rautenbach, D.; Regen, F.;
2010-01-01
For a graph G = (V, E) we consider vertex-k-labellings f : V → {1,2, ,k} for which the induced edge weighting w : E → {2, 3,., 2k} with w(uv) = f(u) + f(v) is injective or surjective or both. We study the relation between these labellings and the number theoretic notions of an additive basis and a...... recent conjecture of Ivančo and Jendroł concerning edge-irregular total labellings for graphs that are sparse enough. © 2010 Societ y for Industrial and Applied Mathematics....
A scintillating-glass fiber optic vertex and tracking detector
International Nuclear Information System (INIS)
High resolution tracking capability is essential for the study of heavy particle production and decay in high energy interactions and for the pattern recognition of high energy events at colliders. Instead of pursuing conventional solutions to the micro-tracking problem such as Si microstrips, drift chambers, or CCDs, we have been following a more unconventional approach, the development of a scintillating glass, fiber-optic imaging system. The initial goal of this program has been to produce a high resolution active target for fixed-target applications; the longer range goal is to exploit the power of fiber-optic techniques for vertex detection and tracking in colliding beam applications
A new tool for constrained vertex fitting in ATLAS
Colijn, Auke Pieter; Limper, Maaike; Prokofiev, Kirill
2009-01-01
The precise reconstruction of trajectories of charged and neutral particles and their decay vertices is crucial for many physics analyses. Studying the tracking performance on well known benchmark channels helps to understand the properties of the ATLAS detector during the initial phase of the LHC. In order to exploit the correlations between reconstructed parameters of final state tracks having the same mother particle, a new tool for vertex fitting with possibility of simultaneous application of kinematic constraints has been developed. Using this tool on a benchmark channel such as J/psi to μ+μ− helps to correct shifts in the reconstructed curvature induced by systematic deformations of the detector.
and as Vertex Operator Extensionsof Dual Affine Algebras
Bowcock, P.; Feigin, B. L.; Semikhatov, A. M.; Taormina, A.
We discover a realisation of the affine Lie superalgebra and of the exceptional affine superalgebra as vertex operator extensions of two algebras with ``dual'' levels (and an auxiliary level-1 algebra). The duality relation between the levels is . We construct the representation of on a sum of tensor products of , , and modules and decompose it into a direct sum over the spectral flow orbit. This decomposition gives rise to character identities, which we also derive. The extension of the construction to is traced to the properties of embeddings into and their relation with the dual pairs. Conversely, we show how the representations are constructed from representations.
From vertex detectors to inner trackers with CMOS pixel sensors
Besson, A.; Pérez, A. Pérez; Spiriti, E.; Baudot, J.; Claus, G; Goffe, M.; de Winter, M.
2016-01-01
The use of CMOS Pixel Sensors (CPS) for high resolution and low material vertex detectors has been validated with the 2014 and 2015 physics runs of the STAR-PXL detector at RHIC/BNL. This opens the door to the use of CPS for inner tracking devices, with 10-100 times larger sensitive area, which require therefore a sensor design privileging power saving, response uniformity and robustness. The 350 nm CMOS technology used for the STAR-PXL sensors was considered as too poorly suited to upcoming ...
The correlation functions of vertex operators and Macdonald polynomials
Cheng, Shun-Jen; Weiqiang WANG
2005-01-01
The n-point correlation functions introduced by Bloch and Okounkov have already found several geometric connections and algebraic generalizations. In this Note we formulate a q,t-deformation of this n-point function. The key operator used in our formulation arises from the theory of Macdonald polynomials and affords a vertex operator interpretation. We obtain closed formulas for the n-point functions when n =1,2 in terms of the basic hypergeometric functions. We further generalize the q,t-def...
Gluon propagator, triple gluon vertex and the QCD coupling constant
International Nuclear Information System (INIS)
We study the UV-scaling of the flavorless gluon propagator in the Landau gauge in an energy window up to 9 GeV. Dominant hypercubic lattice artifacts are eliminated. A large set of renormalization schemes is used to test asymptotic scaling. We compare with our results obtained directly from the triple gluon vertex. We end-up with ΔMS-bar = 318(12)(5) MeV and 292(5)(15) MeV respectively for these two methods, compatible which each other but significantly above the Schroedinger method estimate
Performance of the VTL PEPR vertex guidance system
International Nuclear Information System (INIS)
A PEPR vertex guidance system requiring no operator intervention has been operating at the University of Washington's Visual Techniques Laboratory since 1972. The measurement of 140 000 events consisting of 3, 4, 5, and 6-prong interactions of a 15 GeV/c π- beam with deuterium was recently completed. The system employs global transformations that reduce circular tracks to a point in a two-dimensional angle-curvature space. Noise reduction techniques are used to improve position and angle accuracy and thereby the system resolution and efficiency. Monitoring criteria were developed to ensure continuous peak performance over long production periods. (Auth.)
Hybrid Pixel Detector Development for the Linear Collider Vertex Tracker
Battaglia, Marco; Campagnolo, R; Caccia, M; Kucewicz, W; Jalocha, P; Palka, J; Zalewska-Bak, A
2001-01-01
In order to fully exploit the physics potential of the future high energy e+e- linear collider, a Vertex Tracker able to provide particle track extrapolation with very high resolution is needed. Hybrid Si pixel sensors are an attractive technology due to their fast read-out capabilities and radiation hardness. A novel pixel detector layout with interleaved cells has been developed to improve the single point resolution. Results of the characterisation of the first processed prototypes by electrostatic measurements and charge collection studies are discussed.
Symmetry properties of the sixteen-vertex model
International Nuclear Information System (INIS)
The qualitative symmetry properties of a general two-dimensional model, the sixteen-vertex model are considered. This model admits a rich variety of interpretations. In fact, it can be considered as a kind of master-model, containing as special subclasses various well-known models for phase transitions, such as the Ising model of ferromagnetism both with and without an external field, the dimer model on a square lattice, the ice model and several ferro- and anti-ferro-electric models all of which are of interest in their own right, both theoretically and experimentally. (Auth.)
Vertex Operators Arising from Jacobi-Trudi Identities
Jing, Naihuan; Rozhkovskaya, Natasha
2016-01-01
We give an interpretation of the boson-fermion correspondence as a direct consequence of the Jacobi-Trudi identity. This viewpoint enables us to construct from a generalized version of the Jacobi-Trudi identity the action of a Clifford algebra on the polynomial algebras that arrive as analogues of the algebra of symmetric functions. A generalized Giambelli identity is also proved to follow from that identity. As applications, we obtain explicit formulas for vertex operators corresponding to characters of the classical Lie algebras, shifted Schur functions, and generalized Schur symmetric functions associated to linear recurrence relations.
3D circuit integration for Vertex and other detectors
Energy Technology Data Exchange (ETDEWEB)
Yarema, Ray; /Fermilab
2007-09-01
High Energy Physics continues to push the technical boundaries for electronics. There is no area where this is truer than for vertex detectors. Lower mass and power along with higher resolution and radiation tolerance are driving forces. New technologies such as SOI CMOS detectors and three dimensional (3D) integrated circuits offer new opportunities to meet these challenges. The fundamentals for SOI CMOS detectors and 3D integrated circuits are discussed. Examples of each approach for physics applications are presented. Cost issues and ways to reduce development costs are discussed.
Performance of shortest path algorithm based on parallel vertex traversal
Directory of Open Access Journals (Sweden)
Vesović Mihailo
2016-01-01
Full Text Available Shortest path algorithms for different applications, such as Internet routing, VLSI design and so on are used. Dijkstra and Bellman-Ford are commonly used shortest path algorithms which are typically implemented in networks with hundreds of nodes. However, scale of shortest path problems is increasing, and more efficient algorithms are needed. With the development of multicore processors, one natural way to speedup shortest path algorithms is through parallelization. In this paper, we propose a novel shortest path algorithm with parallel vertex transversal, and compare its speed with standard solutions in datacenter topologies.
Low-Mass Materials and Vertex Detector Systems
Energy Technology Data Exchange (ETDEWEB)
Cooper, William E. [Fermilab
2014-01-01
Physics requirements set the material budget and the precision and sta bility necessary in low - mass vertex detector sy s tems . Operational considerations, along with physics requirements , set the operating environment to be provided and determine the heat to be removed. Representative materials for fulfilling those requirements are described and properties of the materials are tabulated. A figure of merit is proposed to aid in material selection. Multi - layer structures are examined as a method to allow material to be used effectively, thereby reducing material contributions. Fin ally, comments are made on future directions to be considered in using present materials effectively and in developing new materials.
Nonperturbative results on the quark-gluon vertex
Aguilar, A C; Cardona, J C; Papavassiliou, J
2013-01-01
We present analytical and numerical results for the Dirac form factor of the quark-gluon vertex in the quark symmetric limit, where the incoming and outgoing quark momenta have the same magnitude but opposite sign. To accomplish this, we compute the relevant components of the quark-ghost scattering kernel at the one-loop dressed approximation, using as basic ingredients the full quark propagator, obtained as a solution of the quark gap equation, and the gluon propagator and ghost dressing function, obtained from large-volume lattice simulations.
Approximability of the Vertex Cover Problem in Power Law Graphs
Gast, Mikael
2012-01-01
In this paper we construct an approximation algorithm for the Minimum Vertex Cover Problem (Min-VC) with an expected approximation ratio of 2-f(beta) for random Power Law Graphs (PLG) in the (alpha,beta)-model of Aiello et. al., where f(beta) is a strictly positive function of the parameter beta. We obtain this result by combining the Nemhauser and Trotter approach for Min-VC with a new deterministic rounding procedure which achieves an approximation ratio of 3/2 on a subset of low degree vertices for which the expected contribution to the cost of the associated linear program is sufficiently large.
Experience with the L3 vertex drift chamber at LEP
Anderhub, H; Betev, B L; Biland, A; Böhm, A; Bourilkov, D; Camps, C; Commichau, V; Djambazov, L; Göttlicher, P; Hangarter, K; Hofer, H; Holzner, A; Horisberger, Urs; Kopp, A; Leiste, R; Lohmann, W; Lustermann, W; Mnich, J; Paus, C; Pohl, M; Rahal, G; Röser, U; Sassowsky, M; Schäfer, C; Schmidt-Kärst, A S; Schmitz, P; Spickermann, T; Strässner, A; Suter, H; Szczesny, H; Viertel, G; Vogt, H; Von Gunten, H P; Waldmeier, S; Weber, M; Wienemann, P
2003-01-01
The vertex drift chamber of the L3 Experiment at LEP, based on the time expansion principle, was in operation from the start-up of LEP in 1989 until the shutdown of LEP in 2000. The gas mixture used was 80% CO//2 and 20% i-C//4H//1//0 at a pressure of 1200 mbar. We present the design of the chamber, the infrastructure and the performance during the 11 years of operation. The total radiation received on the anode wires was similar to 10**-**4 C/cm. No degradation of the anode pulse amplitude, wire efficiencies and resolution was observed for the whole running period.
The STAR Silicon Strip Detector (SSD)
Arnold, L; Bonnet, D; Boucham, A; Bouvier, S; Castillo, J; Coffin, J P; Drancourt, C; Erazmus, B; Gaudichet, L; Germain, M; Gojak, C; Grabski, J; Guilloux, G; Guedon, M; Hippolyte, B; Janik, M; Kisiel, A; Kuhn, C; Lakehal-Ayat, L; Lefèvre, F; Le Moal, C; Leszczynski, P; Lutz, Jean Robert; Maliszewski, A; Martin, L; Milletto, T; Pawlak, T; Peryt, W; Pluta, J; Przewlocki, M; Radomski, S; Ravel, O; Renard, C; Renault, G; Rigalleau, L M; Roy, C; Roy, D; Suire, C; Szarwas, P; Tarchini, A
2003-01-01
The STAR Silicon Strip Detector (SSD) completes the three layers of the Silicon Vertex Tracker (SVT) to make an inner tracking system located inside the Time Projection Chamber (TPC). This additional fourth layer provides two dimensional hit position and energy loss measurements for charged particles, improving the extrapolation of TPC tracks through SVT hits. To match the high multiplicity of central Au+Au collisions at RHIC the double sided silicon strip technology was chosen which makes the SSD a half million channels detector. Dedicated electronics have been designed for both readout and control. Also a novel technique of bonding, the Tape Automated Bonding (TAB), was used to fullfill the large number of bounds to be done. All aspects of the SSD are shortly described here and test performances of produced detection modules as well as simulated results on hit reconstruction are given.
The Lorentzian proper vertex amplitude: Classical analysis and quantum derivation
Engle, Jonathan
2015-01-01
Spin foam models, an approach to defining the dynamics of loop quantum gravity, make use of the Plebanski formulation of gravity, in which gravity is recovered from a topological field theory via certain constraints called simplicity constraints. However, the simplicity constraints in their usual form select more than just one gravitational sector as well as a degenerate sector. This was shown, in previous work, to be the reason for the "extra" terms appearing in the semiclassical limit of the Euclidean EPRL amplitude. In this previous work, a way to eliminate the extra sectors, and hence terms, was developed, leading to the what was called the Euclidean proper vertex amplitude. In the present work, these results are extended to the Lorentzian signature, establishing what is called the Lorentzian proper vertex amplitude. This extension is non-trivial and involves a number of new elements since, for Lorentzian bivectors, the split into self-dual and anti-self-dual parts, on which the Euclidean derivation was b...
SPARTex: A Vertex-Centric Framework for RDF Data Analytics
Abdelaziz, Ibrahim
2015-08-31
A growing number of applications require combining SPARQL queries with generic graph search on RDF data. However, the lack of procedural capabilities in SPARQL makes it inappropriate for graph analytics. Moreover, RDF engines focus on SPARQL query evaluation whereas graph management frameworks perform only generic graph computations. In this work, we bridge the gap by introducing SPARTex, an RDF analytics framework based on the vertex-centric computation model. In SPARTex, user-defined vertex centric programs can be invoked from SPARQL as stored procedures. SPARTex allows the execution of a pipeline of graph algorithms without the need for multiple reads/writes of input data and intermediate results. We use a cost-based optimizer for minimizing the communication cost. SPARTex evaluates queries that combine SPARQL and generic graph computations orders of magnitude faster than existing RDF engines. We demonstrate a real system prototype of SPARTex running on a local cluster using real and synthetic datasets. SPARTex has a real-time graphical user interface that allows the participants to write regular SPARQL queries, use our proposed SPARQL extension to declaratively invoke graph algorithms or combine/pipeline both SPARQL querying and generic graph analytics.
A $z$-Vertex Trigger for Belle II
Skambraks, Sebastian; Chen, Yang; Feindt, Michael; Frühwirth, Rudolf; Heck, Martin; Kiesling, Christian; Knoll, Alois; Neuhaus, Sara; Paul, Stephan; Schieck, Jochen
2014-01-01
The Belle II experiment will go into operation at the upgraded SuperKEKB collider in 2016. SuperKEKB is designed to deliver an instantaneous luminosity $\\mathcal{L}=8\\times10^{35}\\,\\mathrm{cm}^{-2}\\,\\mathrm{s}^{-1}$. The experiment will therefore have to cope with a much larger machine background than its predecessor Belle, in particular from events outside of the interaction region. We present the concept of a track trigger, based on a neural network approach, that is able to suppress a large fraction of this background by reconstructing the $z$ (longitudinal) position of the event vertex within the latency of the first level trigger. The trigger uses the hit information from the Central Drift Chamber (CDC) of Belle II within narrow cones in polar and azimuthal angle as well as in transverse momentum ("sectors"), and estimates the $z$-vertex without explicit track reconstruction. The preprocessing for the track trigger is based on the track information provided by the standard CDC trigger. It takes input fro...
Natural constraints on the gluon-quark vertex
Binosi, Daniele; Papavassiliou, Joannis; Qin, Si-Xue; Roberts, Craig D
2016-01-01
In principle, the strong-interaction sector of the Standard Model is characterised by a unique renormalisation-group-invariant (RGI) running interaction and a unique form for the dressed--gluon-quark vertex, $\\Gamma_\\mu$; but, whilst much has been learnt about the former, the latter is still obscure. In order to improve this situation, we use a RGI running-interaction that reconciles both top-down and bottom-up analyses of the gauge sector in quantum chromodynamics (QCD) to compute dressed-quark gap equation solutions with 1,660,000 distinct Ansaetze for $\\Gamma_\\mu$. Each one of the solutions is then tested for compatibility with three physical criteria and, remarkably, we find that merely 0.55% of the solutions survive the test. Plainly, therefore, even a small selection of observables places extremely tight bounds on the domain of realistic vertex Ansaetze. This analysis and its results should prove useful in constraining insightful contemporary studies of QCD and hadronic phenomena.
Colour-independent partition functions in coloured vertex models
Foda, O
2013-01-01
We study lattice configurations related to S_n, the scalar product of an off-shell state and an on-shell state in rational A_n integrable vertex models, n = {1, 2}. The lattice lines are colourless and oriented. The state variables are n conserved colours that flow along the line orientations, but do not necessarily cover every bond in the lattice. Choosing boundary conditions such that the positions where the colours flow into the lattice are fixed, and where they flow out are summed over, we show that the partition functions of these configurations, with these boundary conditions, are n-independent. Our results extend to trigonometric A_n models, and to all n. This n-independence explains, in vertex-model terms, results from recent studies of S_2 [1, 2]. Namely, 1. S_2 which depends on two sets of Bethe roots, b_1 and b_2, and cannot (as far as we know) be expressed in single determinant form, degenerates in the limit b_1 -> infinity, and/or b_2 -> infinity, into a product of determinants, 2. Each of the la...
Stochastic Higher Spin Vertex Models on the Line
Corwin, Ivan; Petrov, Leonid
2016-04-01
We introduce a four-parameter family of interacting particle systems on the line, which can be diagonalized explicitly via a complete set of Bethe ansatz eigenfunctions, and which enjoy certain Markov dualities. Using this, for the systems started in step initial data, we write down nested contour integral formulas for moments and Fredholm determinant formulas for Laplace-type transforms. Taking various choices or limits of parameters, this family degenerates to many of the known exactly solvable models in the Kardar-Parisi-Zhang universality class, as well as leads to many new examples of such models. In particular, asymmetric simple exclusion process, the stochastic six-vertex model, q-totally asymmetric simple exclusion process and various directed polymer models all arise in this manner. Our systems are constructed from stochastic versions of the R-matrix related to the six-vertex model. One of the key tools used here is the fusion of R-matrices and we provide a probabilistic proof of this procedure.
Concept and simulation of the CBM-micro vertex detector
International Nuclear Information System (INIS)
The future CBM (Compressed Baryonic Matter) experiment aims to explore the properties of nuclear matter at high net baryonic densities. It will measure rare and penetrating probes such as open charm, which is produced close to the production threshold. The identification of open charmed particles is done by separating their displaced decay vertices from the event vertex. This approach calls for a performant micro vertex detector (MVD), which will consist of several layers of pixel sensors. Monolithic Active Pixel Sensors (MAPS) are currently considered to be the most promising sensor technology for the MVD as they provide an excellent single point resolution together with low material budget and appropriate radiation hardness and time resolution. We will discuss the concept of the MVD. Hereafter, we will introduce the simulation tools used for the detector simulation. A focus will be laid on the digitizer for the MAPS. The simulated response of the MAPS will be compared with data obtained from beam tests at the CERN-SPS.
Guarding curvilinear art galleries with vertex or point guards
Karavelas, Menelaos I
2008-01-01
One of the earliest and most well known problems in computational geometry is the so-called art gallery problem. The goal is to compute the minimum possible number guards placed on the vertices of a simple polygon in such a way that they cover the interior of the polygon. In this paper we consider the problem of guarding an art gallery which is modeled as a polygon with curvilinear walls. Our main focus is on polygons the edges of which are convex arcs pointing towards the exterior or interior of the polygon (but not both), named piecewise-convex and piecewise-concave polygons. We prove that, in the case of piecewise-convex polygons, if we only allow vertex guards, $\\lfloor\\frac{4n}{7}\\rfloor-1$ guards are sometimes necessary, and $\\lfloor\\frac{2n}{3}\\rfloor$ guards are always sufficient. Moreover, an $O(n\\log{}n)$ time and $O(n)$ space algorithm is described that produces a vertex guarding set of size at most $\\lfloor\\frac{2n}{3}\\rfloor$. When we allow point guards the afore-mentioned lower bound drops down ...
International Nuclear Information System (INIS)
The Forward Silicon Vertex Tracker (FVTX) upgrade for the PHENIX detector at RHIC will extend the vertex capability of the central PHENIX Silicon Vertex Tracker (VTX). The FVTX is designed with adequate spatial resolution to separate decay muons coming from the relatively long-lived heavy quark mesons (Charm and Beauty), from prompt particles and the longer-lived pion and kaon decays that originate at the primary collision vertex. These heavy quarks can be used to probe the high-density medium that is formed in Au+Au collisions at RHIC. The FVTX is designed as two endcaps. Each endcap comprises four silicon disks covering opening angles from 10o to 35o to match the existing muon arm acceptance. Each disk consists of p-on-n, silicon wedges, with ac-coupled mini-strips on 75 μm radial pitch and projective length in the phi direction that increases with radius. A custom front-end chip, the FPHX, has been designed for the FVTX. The chip combines fast trigger capability with data push architecture in a low-power design.
International Nuclear Information System (INIS)
The Resistive Plate Chambers (RPCs) initially installed in the Instrumented Flux Return (IFR) of the BABAR particle detector have proven unreliable and inefficient for detecting muons and neutral hadrons. In the summer of 2004, the BABAR Collaboration began replacing the RPCs with Limited Streamer Tubes (LSTs). LST operation requires a mixture of very pure gases and an operating voltage of 5500 V to achieve maximum efficiency. In the past, the gas supplies obtained by the BABAR Collaboration have contained contaminants that caused the efficiency of the IFR LSTs to drop from approximately 90% to approximately 60%. Therefore, it was necessary to develop a method for testing this gas for contaminants. An LST test system was designed and built using two existing LSTs, one placed 1 cm above the other. These LSTs detect cosmic muons in place of particles created during the BABAR experiment. The effect of gas contamination was mimicked by reducing the operating voltage of the test system in order to lower the detection efficiency. When contaminated gas was simulated, the coincidence rate and the percent coincidence between the LSTs in the test system dropped off significantly, demonstrating that test system can be used as an indicator of gas purity. In the fall of 2006, the LST test system will be installed in the gas storage area near the BABAR facility for the purpose of testing the gas being sent to the IFR
Energy Technology Data Exchange (ETDEWEB)
O`Connor, T.G.; Bell, R. [Lawrence Livermore National Lab., CA (United States); Fabbricatore, P. [Istituto Nazionale di Fisica Nucleare, Genoa (Italy); Giorgi, M.; Hitlin, D. [BABAR Collaboration (Italy)
1997-03-07
This document sets forth the specification of the BABAR superconducting solenoid and power supply which is being supplied to the BABAR collaboration by INSTITUTO NAZIONALE DI FISICA NUCLEARE (INFN). The solenoid will be installed in the BABAR detector which will be located at Interaction Region 2 (IR2) of the PEP II machine, a positron electron collider, presently under construction at the Stanford Linear Accelerator Center (SLAC) located in Menlo Park, California. The solenoid will become part of the BABAR detector which will be used in SLAC`s high energy physics program. Intense beams of electrons and positrons are made to collide inside the solenoid magnet. High field uniformity quality, precise mechanical alignment and long term stability are essential characteristics of the solenoid. INFN will set up a committee that will provide contractual and technical oversight throughout the design, fabrication and installation phases of the BABAR solenoid construction. That committee will be the final authority to resolve any differences between these specifications and the INFN supplied drawings, in addition to any differences between these specifications or the INFN supplied drawings and the proposals from the vendor. All submissions for approval to INFN whether for design changes, material approval, design submissions or others as required by this specification shall be acted upon INFN within two (2) weeks of receipt of the submissions. If no answer is given the vendor may assume approval and proceed.
Characterisation of micro-strip and pixel silicon detectors before and after hadron irradiation
Allport, P. P.
2012-01-01
The use of segmented silicon detectors for tracking and vertexing in particle physics has grown substantially since their introduction in 1980. It is now anticipated that roughly 50,000 six inch wafers of high resistivity silicon will need to be processed into sensors to be deployed in the upgraded experiments in the future high luminosity LHC (HL-LHC) at CERN. These detectors will also face an extremely severe radiation environment, varying with distance from the interaction point. The volum...
Reflection matrices for the Uq[sl(m|n)(1)] vertex model
International Nuclear Information System (INIS)
We investigate the possible regular solutions of the boundary Yang–Baxter equation for the vertex models associated with the graded version of the An−1(1) affine Lie algebra, the Uq[sl(m|n)(1)] vertex model, also known as the Perk–Schultz model
Drinfeld twist and the domain wall partition function of the eight-vertex model
Institute of Scientific and Technical Information of China (English)
Hao Kun; Chen xi; Shi Kang-Jie; Yang Wen-Li
2011-01-01
With the help of the F-basis provided by the Drinfeld twist or factorising F-matrix for the spatial optical soliton model associated with the eight-vertex model, we calculate the partition function for the eight-vertex model on an N × N square lattice with domain wall boundary condition.
Type II vertex operators for the $A_{n-1}^{(1)}$ face model
Furutsu, H; Quano, Y H
1999-01-01
Presented is a free boson representation of the type II vertex operators for the $A_{n-1}^{(1)}$ face model. Using the bosonization, we derive some properties of the type II vertex operators, such as commutation, inversion and duality relations.
Lambda: A Mathematica-package for operator product expansions in vertex algebras
Ekstrand, Joel
2010-01-01
We give an introduction to the Mathematica package Lambda, designed for calculating $\\lambda$-brackets in both vertex algebras, and in SUSY vertex algebras. This is equivalent to calculating operator product expansions in two-dimensional conformal field theory. The syntax of $\\lambda$-brackets is reviewed, and some simple examples are shown, both in component notation, and in $N=1$ superfield notation.
Lambda: A Mathematica-package for operator product expansions in vertex algebras
Ekstrand, Joel
2010-01-01
We give an introduction to the Mathematica package Lambda, designed for calculating {\\lambda}-brackets in both vertex algebras, and in SUSY vertex algebras. This is equivalent to calculating operator product expansions in two-dimensional conformal field theory. The syntax of {\\lambda}-brackets is reviewed, and some simple examples are shown, both in component notation, and in N=1 superfield notation.
Instanton-induced Effective Vertex in the Seiberg-Witten Theory with Matter
Lee, B K; Lee, ByungKoo; Nam, Soonkeon
1997-01-01
The instanton-induced effective vertex is derived for N=2 supersymmetric QCD (SQCD) with arbitrary mass matter hypermultiplets for the case of SU(2). The leading term of the low energy effective lagrangian obtained from this vertex agrees with one-instanton effective term of the Seiberg-Witten result.
Radiative corrections to the quark-gluon-Reggeized quark vertex in QCD
International Nuclear Information System (INIS)
This paper is devoted to the calculation of quark-gluon-Reggeized quark effective vertex in perturbative QCD in the next-to-leading order. The case of QCD with massive quarks is considered. This vertex has a number of applications, in particular, the result can be used for determination of the next-to-leading correction to the massive Reggeized quark trajectory
A momentum space analysis of the Triple Pomeron Vertex in pQCD
Energy Technology Data Exchange (ETDEWEB)
Bartels, J. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Kutak, K. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)]|[Instytut Fizyki Jadrowej Polskiej Akademii Nauk, Krakow (Poland)
2007-10-15
We study properties of the momentum space Triple Pomeron Vertex in perturbative QCD. Particular attention is given to the collinear limit where transverse momenta on one side of the vertex are much larger than on the other side. We also comment on the kernels in nonlinear evolution equations. (orig.)