Online Pattern Recognition for the ALICE High Level Trigger

The ALICE High Level Trigger has to process data online, in order to select interesting (sub)events, or to compress data efficiently by modeling techniques.Focusing on the main data source, the Time Projection Chamber (TPC), we present two pattern recognition methods under investigation: a sequential approach "cluster finder" and "track follower") and an iterative approach ("track candidate finder" and "cluster deconvoluter"). We show, that the former is suited for pp and low multiplicity PbPb collisions, whereas the latter might be applicable for high multiplicity PbPb collisions, if it turns out, that more than 8000 charged particles would have to be reconstructed inside the TPC. Based on the developed tracking schemes we show, that using modeling techniques a compression factor of around 10 might be achievableComment: Realtime Conference 2003, Montreal, Canada to be published in IEEE Transactions on Nuclear Science (TNS), 6 pages, 8 figure

Elliptic flow in Au+Au collisions at sqrt sNN = 130 GeV

Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at sqrt[sNN] = 130 GeV using the STAR Time Projection Chamber at the Relativistic Heavy Ion Collider. The elliptic flow signal, v2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.alle Autoren: K. H. Ackermann19, N. Adams28, C. Adler12, Z. Ahammed27, S. Ahmad28, C. Allgower13, J. Amsbaugh34, M. Anderson6, E. Anderssen17, H. Arnesen3, L. Arnold14, G. S. Averichev10, A. Baldwin16, J. Balewski13, O. Barannikova10,27, L. S. Barnby16, J. Baudot14, M. Beddo1, S. Bekele24, V. V. Belaga10, R. Bellwied35, S. Bennett35, J. Bercovitz17, J. Berger12, W. Betts24, H. Bichsel34, F. Bieser17, L. C. Bland13, M. Bloomer17, C. O. Blyth4, J. Boehm17, B. E. Bonner28, D. Bonnet14, R. Bossingham17, M. Botlo3, A. Boucham30, N. Bouillo30, S. Bouvier30, K. Bradley17, F. P. Brady6, E. S. Braithwaite2, W. Braithwaite2, A. Brandin21, R. L. Brown3, G. Brugalette34, C. Byrd2, H. Caines24, M. Calderón de la Barca Sánchez36, A. Cardenas27, L. Carr34, J. Carroll17, J. Castillo30, B. Caylor17, D. Cebra6, S. Chatopadhyay35, M. L. Chen3, W. Chen3, Y. Chen7, S. P. Chernenko10, M. Cherney9, A. Chikanian36, B. Choi31, J. Chrin9, W. Christie3, J. P. Coffin14, L. Conin30, C. Consiglio3, T. M. Cormier35, J. G. Cramer34, H. J. Crawford5, V. I. Danilov10, D. Dayton3, M. DeMello28, W. S. Deng16, A. A. Derevschikov26, M. Dialinas30, H. Diaz3, P. A. DeYoung8, L. Didenko3, D. Dimassimo3, J. Dioguardi3, W. Dominik32, C. Drancourt30, J. E. Draper6, V. B. Dunin10, J. C. Dunlop36, V. Eckardt19, W. R. Edwards17, L. G. Efimov10, T. Eggert19, V. Emelianov21, J. Engelage5, G. Eppley28, B. Erazmus30, A. Etkin3, P. Fachini29, C. Feliciano3, D. Ferenc6, M. I. Ferguson7, H. Fessler19, E. Finch36, V. Fine3, Y. Fisyak3, D. Flierl12, I. Flores5, K. J. Foley3, D. Fritz17, N. Gagunashvili10, J. Gans36, M. Gazdzicki12, M. Germain14, F. Geurts28, V. Ghazikhanian7, C. Gojak14, J. Grabski33, O. Grachov35, M. Grau3, D. Greiner17, L. Greiner5, V. Grigoriev21, D. Grosnick1, J. Gross9, G. Guilloux30, E. Gushin21, J. Hall35, T. J. Hallman3, D. Hardtke17, G. Harper34, J. W. Harris36, P. He5, M. Heffner6, S. Heppelmann25, T. Herston27, D. Hill1, B. Hippolyte14, A. Hirsch27, E. Hjort27, G. W. Hoffmann31, M. Horsley36, M. Howe34, H. Z. Huang7, T. J. Humanic24, H. Hümmler19, W. Hunt13, J. Hunter17, G. J. Igo7, A. Ishihara31, Yu. I. Ivanshin11, P. Jacobs17, W. W. Jacobs13, S. Jacobson17, R. Jared17, P. Jensen31, I. Johnson17, P. G. Jones4, E. Judd5, M. Kaneta17, M. Kaplan8, D. Keane16, V. P. Kenney23*, A. Khodinov21, J. Klay6, S. R. Klein17, A. Klyachko13, G. Koehler17, A. S. Konstantinov26, V. Kormilitsyne7,26, L. Kotchenda21, I. Kotov24, A. D. Kovalenko10, M. Kramer22, P. Kravtsov21, K. Krueger1, T. Krupien3, P. Kuczewski3, C. Kuhn14, G. J. Kunde36, C. L. Kunz8, R. Kh. Kutuev11, A. A. Kuznetsov10, L. Lakehal-Ayat30, J. Lamas-Valverde28, M. A. C. Lamont4, J. M. Landgraf3, S. Lange12, C. P. Lansdell31, B. Lasiuk36, F. Laue24, A. Lebedev3, T. LeCompte1, W. J. Leonhardt3, V. M. Leontiev26, P. Leszczynski33, M. J. LeVine3, Q. Li35, Q. Li17, Z. Li3, C.-J. Liaw3, J. Lin9, S. J. Lindenbaum22, V. Lindenstruth5, P. J. Lindstrom5, M. A. Lisa24, H. Liu16, T. Ljubicic3, W. J. Llope28, G. LoCurto19, H. Long7, R. S. Longacre3, M. Lopez-Noriega24, D. Lopiano1, W. A. Love3, J. R. Lutz14, D. Lynn3, L. Madansky15§, R. Maier19, R. Majka36, A. Maliszewski33, S. Margetis16, K. Marks17, R. Marstaller19, L. Martin30, J. Marx17, H. S. Matis17, Yu. A. Matulenko26, E. A. Matyushevski10, C. McParland17, T. S. McShane9, J. Meier9, Yu. Melnick26, A. Meschanin26, P. Middlekamp3, N. Mikhalin7,26, B. Miller3, Z. Milosevich8, N. G. Minaev26, B. Minor17, J. Mitchell15, E. Mogavero3, V. A. Moiseenko11, D. Moltz17, C. F. Moore31, V. Morozov17, R. Morse17, M. M. de Moura29, M. G. Munhoz29, G. S. Mutchler28, J. M. Nelson4, P. Nevski3, T. Ngo7, M. Nguyen3, T. Nguyen3, V. A. Nikitin11, L. V. Nogach26, T. Noggle17, B. Norman16, S. B. Nurushev26, T. Nussbaum28, J. Nystrand17, G. Odyniec17, A. Ogawa25, C. A. Ogilvie18, K. Olchanski3, M. Oldenburg19, D. Olson17, G. A. Ososkov10, G. Ott31, D. Padrazo3, G. Paic24, S. U. Pandey35, Y. Panebratsev10, S. Y. Panitkin16, A. I. Pavlinov26, T. Pawlak33, M. Pentia10, V. Perevotchikov3, W. Peryt33, V. A Petrov11, W. Pinganaud30, S. Pirogov7, E. Platner28, J. Pluta33, I. Polk3, N. Porile27, J. Porter3, A. M. Poskanzer17, E. Potrebenikova10, D. Prindle34, C. Pruneau35, J. Puskar-Pasewicz13, G. Rai17, J. Rasson17, O. Ravel30, R. L. Ray31, S. V. Razin10,13, D. Reichhold9, J. Reid34, R. E. Renfordt12, F. Retiere30, A. Ridiger21, J. Riso35, H. G. Ritter17, J. B. Roberts28, D. Roehrich12, O. V. Rogachevski10, J. L. Romero6, C. Roy30, D. Russ8, V. Rykov35, I. Sakrejda17, R. Sanchez7, Z. Sandler7, J. Sandweiss36, P. Sappenfield28, A. C. Saulys3, I. Savin11, J. Schambach31, R. P. Scharenberg27, J. Scheblien3, R. Scheetz3, R. Schlueter17, N. Schmitz19, L. S. Schroeder17, M. Schulz3,19, A. Schüttauf19, J. Sedlmeir3, J. Seger9, D. Seliverstov21, J. Seyboth19, P. Seyboth19, R. Seymour34, E. I. Shakaliev10, K. E. Shestermanov26, Y. Shi7, S. S. Shimanskii10, D. Shuman17, V. S. Shvetcov11, G. Skoro10, N. Smirnov36, L. P. Smykov10, R. Snellings17, K. Solberg13, J. Sowinski13, H. M. Spinka1, B. Srivastava27, E. J. Stephenson13, R. Stock12, A. Stolpovsky35, N. Stone3, R. Stone17, M. Strikhanov21, B. Stringfellow27, H. Stroebele12, C. Struck12, A. A. P. Suaide29, E. Sugarbaker24, C. Suire14, T. J. M. Symons17, J. Takahashi29, A. H. Tang16, A. Tarchini14, J. Tarzian17, J. H. Thomas17, V. Tikhomirov21, A. Szanto de Toledo29, S. Tonse17, T. Trainor34, S. Trentalange7, M. Tokarev10, M. B. Tonjes20, V. Trofimov21, O. Tsai7, K. Turner3, T. Ullrich36, D. G. Underwood1, I. Vakula7, G. Van Buren3, A. M. VanderMolen20, A. Vanyashin17, I. M. Vasilevski11, A. N. Vasiliev26, S. E. Vigdor13, G. Visser5, S. A. Voloshin35, C. Vu17, F. Wang27, H. Ward31, D. Weerasundara34, R. Weidenbach17, R. Wells17, R. Wells24, T. Wenaus3, G. D. Westfall20, J. P. Whitfield8, C. Whitten, Jr.7, H. Wieman17, R. Willson24, K. Wilson35, J. Wirth17, J. Wisdom7, S. W. Wissink13, R. Witt16, J. Wolf17, L. Wood6, N. Xu17, Z. Xu36, A. E. Yakutin26, E. Yamamoto7, J. Yang7, P. Yepes28, A. Yokosawa1, V. I. Yurevich10, Y. V. Zanevski10, J. Zhang17, W. M. Zhang16, J. Zhu34, D. Zimmerman17, R. Zoulkarneev11, and A. N. Zubare

Rapidity-dependent chemical potentials in a statistical approach

We present a single-freeze-out model with thermal and geometric parameters dependent on the position within the fireball and use it to describe the rapidity and transverse-momentum spectra of pions, kaons, protons, and antiprotons measured at RHIC at 200 GeV} by BRAHMS. THERMINATOR is used to perform the necessary simulation, which includes all resonance decays. The result of the fit to the data is the expected growth of the baryon and strange chemical potentials with the spatial rapidity\alpha_\parallel. The value of the baryon chemical potential at \alpha_\parallel ~ 3 is about 200 MeV, i.e. lies in the range of the highest SPS energies. The chosen geometry of the fireball has a decreasing transverse size as the magnitude of \alpha_\parallel is increased, which also corresponds to decreasing transverse flow. The strange chemical potential obtained from the fit to the K+/K- ratio is such that the local strangeness density in the fireball is compatible with zero. The resulting rapidity spectra of net protons are described qualitatively within the statistical approach. As a result of our study, the knowledge of the ``topography'' of the fireball is acquired, allowing for other analyses and predictions.Comment: 6 pages, tals at SQM 200

Recent results on strangeness production from NA49

We present a summary of measurements of strange particles performed by the experiment NA49 in inelastic p+p interactions, as well as semi-central C+C and Si+Si, central Pb+Pb, and minimum bias Pb+Pb collisions in the energy range $\sqrt{s_{NN}}$ = 6.3 - 17.3 GeV. New results on $\pi^{-}$, $K^{+}$ and $K^{-}$ production in minimum bias Pb+Pb collisions at $\sqrt{s_{NN}}$ = 8.7 and 17.3 are shown. Furthermore the strangeness enhancement factor at $\sqrt{s_{NN}}$ = 17.3 GeV is presented and compared to the results from NA57 and STAR. Energy dependence of strange particle yields normalized to pion yields is presented. New data on $$ production are shown at $\sqrt{s_{NN}}$ = 17.3 GeV. Furthermore we present the energy dependence of $K/\pi$ and $K/p$ fluctuations. The data are compared with model predictions.Comment: 9 pages, 7 figures, Submitted to J. Phys. G (Proceedings of the International Conference on Strangeness in Quark Matter, Buzios, Rio de Janeiro, Brazil, September 27 - October 2, 2009

Development of Wireless Techniques in Data and Power Transmission - Application for Particle Physics Detectors

Wireless techniques have developed extremely fast over the last decade and using them for data and power transmission in particle physics detectors is not science- fiction any more. During the last years several research groups have independently thought of making it a reality. Wireless techniques became a mature field for research and new developments might have impact on future particle physics experiments. The Instrumentation Frontier was set up as a part of the SnowMass 2013 Community Summer Study [1] to examine the instrumentation R&D for the particle physics research over the coming decades: {\guillemotleft} To succeed we need to make technical and scientific innovation a priority in the field {\guillemotright}. Wireless data transmission was identified as one of the innovations that could revolutionize the transmission of data out of the detector. Power delivery was another challenge mentioned in the same report. We propose a collaboration to identify the specific needs of different projects that might benefit from wireless techniques. The objective is to provide a common platform for research and development in order to optimize effectiveness and cost, with the aim of designing and testing wireless demonstrators for large instrumentation systems

The Relationship of the Mississippian Charles formation to the Structure of the Nesson Anticline of North Dakota

An isopach map superimposed upon a structure contour map of the Charles formation shows a definite thinning of the Charles over the structurally high areas of the Nesson Anticline of North Dakota. It is here suggested that this fact be used to help exploration for oil in the area

Source Dimensions in Ultrarelativistic Heavy Ion Collisions

Recent experiments on pion correlations, interpreted as interferometric measurements of the collision zone, are compared with models that distinguish a prehadronic phase and a hadronic phase. The models include prehadronic longitudinal expansion, conversion to hadrons in local kinetic equilibrium, and rescattering of the produced hadrons. We find that the longitudinal and outward radii are surprisingly sensitive to the algorithm used for two-body collisions. The longitudinal radius measured in collisions of 200 GeV/u sulfur nuclei on a heavy target requires the existence of a prehadronic phase which converts to the hadronic phase at densities around 0.8-1.0 GeV/fm$^3$. The transverse radii cannot be reproduced without introducing more complex dynamics into the transverse expansion.Comment: RevTeX 3.0, 28 pages, 6 figures, not included, revised version, major change is an additional discussion of the classical two-body collision algorithm, a (compressed) postscript file of the complete paper including figures can be obtained from Authors or via anonymous ftp at ftp://ftp_int.phys.washington.edu/pub/herrmann/pisource.ps.

NA61/SHINE facility at the CERN SPS: beams and detector system

NA61/SHINE (SPS Heavy Ion and Neutrino Experiment) is a multi-purpose experimental facility to study hadron production in hadron-proton, hadron-nucleus and nucleus-nucleus collisions at the CERN Super Proton Synchrotron. It recorded the first physics data with hadron beams in 2009 and with ion beams (secondary 7Be beams) in 2011. NA61/SHINE has greatly profited from the long development of the CERN proton and ion sources and the accelerator chain as well as the H2 beamline of the CERN North Area. The latter has recently been modified to also serve as a fragment separator as needed to produce the Be beams for NA61/SHINE. Numerous components of the NA61/SHINE set-up were inherited from its predecessors, in particular, the last one, the NA49 experiment. Important new detectors and upgrades of the legacy equipment were introduced by the NA61/SHINE Collaboration. This paper describes the state of the NA61/SHINE facility - the beams and the detector system - before the CERN Long Shutdown I, which started in March 2013

Signatures of Quark-Gluon-Plasma formation in high energy heavy-ion collisions: A critical review

A critical review on signatures of Quark-Gluon-Plasma formation is given and the current (1998) experimental status is discussed. After giving an introduction to the properties of QCD matter in both, equilibrium- and non-equilibrium theories, we focus on observables which may yield experimental evidence for QGP formation. For each individual observable the discussion is divided into three sections: first the connection between the respective observable and QGP formation in terms of the underlying theoretical concepts is given, then the relevant experimental results are reviewed and finally the current status concerning the interpretation of both, theory and experiment, is discussed. A comprehensive summary including an outlook towards RHIC is given in the final section.Comment: Topical review, submitted to Journal of Physics G: 68 pages, including 39 figures (revised version: only minor modifications, some references added