1 / 15

Pawan Kumar Netrakanti,VECC, Kolkata (For STAR Collaboration)

Identified hadron spectra at large transverse momentum in p + p and d +Au collisions at  s NN = 200 GeV. Pawan Kumar Netrakanti,VECC, Kolkata (For STAR Collaboration). STAR preliminary. STAR preliminary. Outline. Motivation Method of analysis Results from p + p collisions

enye
Download Presentation

Pawan Kumar Netrakanti,VECC, Kolkata (For STAR Collaboration)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Identified hadron spectra at large transverse momentum in p+p and d+Au collisions at sNN=200 GeV Pawan Kumar Netrakanti,VECC, Kolkata (For STAR Collaboration) QGP-MEET 2006, VECC, February 2006

  2. STAR preliminary STAR preliminary Outline • Motivation • Method of analysis • Results from p+p collisions • Results from d+Au collisions • Summary QGP-MEET 2006, VECC, February 2006

  3. Motivation HighpT PID in TPC Test predictions (certain aspects) of pQCD Understanding Nuclear effects in d+Au collisions QGP-MEET 2006, VECC, February 2006

  4. Log10(dE/dx) Log10(p) High pT :Extend particle identification in TPC by exploiting the relativistic rise in ionization energy loss. Hadron identification: STAR Collaboration, nucl-ex/0309012 • Intrinsic timing resolution: 85 ps • Coverage : -1.0 < h< 0.0 and 60o in f • low pT particle identification ( < 2.5 GeV/c) in this study Momentum: GeV/c dE/dx of p (K,p) separation: 2s Method of analysis • Low pT Time of Flight (TOF) • High pT Time Projection Chamber (TPC) Coverage: |h|<1.8 and f symmetric QGP-MEET 2006, VECC, February 2006

  5. STAR preliminary Power-law : ( A/(1 + pT/p0)n) Levy : (B/(1+(mT-m0)/nT)n) Transverse Momentum Spectra • Power-law function ~ pQCD inspired • Levy ~ exponential + power-law Power law type behavior for p+p and d+Au collisions at high pT QGP-MEET 2006, VECC, February 2006

  6. NLO pQCD with KKP FFinconsistent with the p+pbar data NLO pQCD with AKK FF relatively better than KKP for the p+pbar data NLO pQCD with Kretzer FF inconsistent with data Kretzer differ from KKP, in the gluon to p fragmentation AKK differ from KKP, in the way the light flavor FF are obtained Comparison toNLO pQCD QGP-MEET 2006, VECC, February 2006

  7. p+p collisions and phenomenological model Phenomenological EPOS Model are consistent with pion data, even at low pT. Phenomenological EPOS Model are consistent with p + pbar data, even at low pT. Interesting to observe that two different models (pQCD and EPOS) do a reasonable job in p+p collisions K. Werner, F. Liu and T. Pierog, hep-ph/0506232 QGP-MEET 2006, VECC, February 2006

  8. Scaling in particle production e+ and e- does not have a parton distribution function. There will be a (sNN )2 multiplied to cross-section in e+e- collisions. For p+p collisions n ~ 6.5 for p, p (pbar) QGP-MEET 2006, VECC, February 2006

  9. STAR Preliminary d+Au collisions and models • NLO pQCD calculations • with KKP and AKK FF and • EPOS are consistent with • pion data at high pT (> 4 GeV/c) • pQCD calculations with Kretzer FF under predicts pion data • NLO pQCD calculations • with only AKK fragmentation • function consistent with the • p+pbar data Parton distribution functions : L. Frankfurt, et al., Phys. Rev. D 71 (2005) 054001 D. De Florian and R. Sassot, PRD 69 (2004) 074028 QGP-MEET 2006, VECC, February 2006

  10. STAR preliminary STAR preliminary Nuclear Modification Factor : d+Au collisions Phys. Rev. Lett. 91 (2003) 072304 • RdAu for p > 1, Cronin effect • Absence of high pT suppression in particle production • RdAu (p + pbar) > RdAu(p) Similar dependence has been observed at lower energies. Phys. Rev D 19 (1979) 764 Qualitative agreement with recombination model for dAu collisions. Phys.Rev.Lett.93 (2004) 082302 QGP-MEET 2006, VECC, February 2006

  11. Particle Ratios – p+p collisions • p-/p+ ~ 1andpbar/p ~ 0.8 • PYTHIA predicts a more prominent pTdependence • p/p+ and pbar/p- increases with pT~ 2 GeV/c and then decreases to ~ 0.2 • p/p+ agrees with lower energy results. • pbar/p-shows a distinct energy dependence QGP-MEET 2006, VECC, February 2006

  12. STAR preliminary Particle Ratios – d+Au collisions • p -/p+ ~ 1- independent of pT • pbar/p decreases with pT • p/p+ and pbar/p - increases with pT up to 2 GeV/c and then decreases. QGP-MEET 2006, VECC, February 2006

  13. Highlight and Summary • NLO pQCD describes the p+pbar spectrum for the first time in p+p collisions • These results show the importance of the significant improvement of FF for baryons from the light-flavor separated measurements in e+e- collisions (OPAL) • The observed xT scaling of p,p(pbar) at high pT also show dominance of hard processes related to PDF and FF • Provide solid reference for effects of jet quenching and recombination in Nucleus-Nucleus collisions Details of these results can be found at: arXive: nucl-ex/0601033 QGP-MEET 2006, VECC, February 2006

  14. STAR The STAR Collaboration U.S. Labs: Argonne, Lawrence Berkeley, and Brookhaven National Labs U.S. Universities: UC Berkeley, UC Davis, UCLA, Caltech, Carnegie Mellon, Creighton, Indiana, Kent State, MIT, MSU, CCNY, Ohio State, Penn State, Purdue, Rice, Texas A&M, UT Austin, Washington, Wayne State, Valparaiso, Yale Brazil: Universidade de Sao Paolo China: IHEP - Beijing, IPP - Wuhan, USTC, Tsinghua, SINAP, IMP Lanzhou Croatia: Zagreb University Czech Republic: Nuclear Physics Institute England: University of Birmingham France: Institut de Recherches Subatomiques Strasbourg, SUBATECH - Nantes Germany: Max Planck Institute – Munich University of Frankfurt India: Bhubaneswar, Jammu, IIT-Mumbai, Panjab, Rajasthan, VECC, Kolkata Netherlands: NIKHEF/Utrecht Poland: Warsaw University of Technology Russia: MEPHI – Moscow, LPP/LHE JINR – Dubna, IHEP – Protvino South Korea: Pusan National University Switzerland: University of Bern QGP-MEET 2006, VECC, February 2006

  15. STAR preliminary Scaling of particle production mT scaling observed for 1 < mT < 2 GeV/c2 At high pT : no scaling Mass effect Or baryon-meson effect QGP-MEET 2006, VECC, February 2006

More Related