1 / 20

Future prospects for NA61 heavy ions: rare observables

Future prospects for NA61 heavy ions: rare observables. Connecting to high-energy (RHIC) results. M. van Leeuwen, Utrecht University and the NA61 collaboration. Workshop: New Opportunities in the Physics Landscape at CERN 11-14 May 2009. Motivation.

flavian-myles
Download Presentation

Future prospects for NA61 heavy ions: rare observables

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. Future prospects for NA61 heavy ions: rare observables Connecting to high-energy (RHIC) results M. van Leeuwen, Utrecht University and the NA61 collaboration Workshop: New Opportunities in the Physics Landscape at CERN 11-14 May 2009

  2. Motivation • Heavy ion collisions: study strong interactions bulk matter • Identify phase transition to Quark-Gluon-Plasma • Pure bulk = soft QCD, theoretically difficult • Hard-soft interplay studied at RHIC shows many unexpected results – do these effects exist at SPS energies? • Can we ‘switch off’ some effects – transition ?

  3. Jet-like di-hadron correlations at RHIC Combinatorialbackground STAR, PRL97, 162301 8 < pTtrig < 15 GeV associated pTassoc > 3 GeV  trigger Near side Away side p+p event display Use di-hadron correlations to probe the jet-structure in p+p, d+Au and Au+Au At high pT > 4-6 GeV: Clear di-jet signature Away-side suppression due to energy loss

  4. Lowering pT: bulk response? d+Au, 200 GeV 3.0 < pTtrig < 4.0 GeV/c Jet-like peak 1.3 < pTassoc < 1.8 GeV/c 3 < pt,trigger < 4 GeV pt,assoc. > 2 GeV Au+Au 0-10% STAR preliminary STAR, Putschke et al STAR, M. Horner, M. van Leeuwen, et al Near side Enhanced yield in Au+Au Away-side: Strong broadening in central Au+Au ‘Dip’ at  =  `Ridge’: associated yield at large  dN/d approx. independent of  Large modifications of di-hadron structure at intermediate pT Modified fragmentation? Bulk response?

  5. Comparing SPS and RHIC M. Szuba, Hot Quarks 2008 SPS full energy: di-hadron structure similar to RHIC yields lower  lower ‘jet’ energy

  6. Energy dependence of di-hadron correlations at SPS 40 AGeV 20 AGeV M. Szuba, HQ08 Qualitative change from low to high energy: from near-side dip to near-side peak Clear turn-on as a function of energy. What is the mechanism? New data needed to study h, pT-dependence, above and below transition

  7. Charm production at RHIC STAR, PRL 98 (2007) 192301 Low pT, RAA~ 1 Total cross section scales with Ncoll as expected Suppression at high-pt: charm interacts with medium Does charm thermalise?Measure charm spectra at low pt, v2 Will be measured at RHIC (STAR, PHENIX upgrades) and LHC (ALICE, others?) Can we measure this at SPS? Thermalised charm at SPS?

  8. Charm with NA61? N(D0+D0) = -0.36  0.74 per event N(D0+D0) < 1.5 per event (C.L. 98%) N(D0+D0) expected: ~ 0.11 per central event NA49: D0K p 3.8M events Phys.Rev.C73:034910,2006 NA61: cm+ m- EPJ C59, 607 Would need ~300M events (300 days running) for 1s  Need vertex detector to measure D0, pT spectra, v2 e.g. 20M central events gives 80k D0K p

  9. Technology candidate: GOSSIP H. van der Graaf et al., NIKHEF GridPix/InGrid GOSSIP Gas on Slimmed Silicon Pixels Gas amplification + pixel readout Use time-dependence toimage track in gas layer Pixel size 55 x 55 mm + time Thin, precise and cheap !

  10. Occupancy for vertex detector 2-track distance Hits at z = 10 cm ycms < 1 Central Pb+Pb at 158 AGeV For y < 4 ~ R > 0.3 cm, two-track distance ~ 300 mm z = 10 cm safe choice for first plane

  11. Vertex resolution with vertex detector Decay distance along beam Decay length resolution 158 AGeV collisions Including Mult scatt ~600 mm Si per plane Geometry:6 planes, 10, 15 … 40 cm Lorentz boost: large decay lengths (mm scale) Looks promising: typical decay length >> resolution

  12. Summary of proposal • 2 runs of NA61 ~10 weeks, 70M events(after baseline heavy ion program, 2014+) • Highest SPS energy: 158 AGeV • Low energy: 20/30 AGeV • Measurement 1: jet-like di-hadron structure • Peak-dip transition, explore pT-dependence, h-j structure – connection to bulk response effects at RHIC • Measurement 2: charm production • Need vertex detector • Measure yield, pT spectra (radial flow) and v2?

  13. Towards a 4p detector? Concept: a large acceptance detector for ‘all’ particles (EM + charged hadrons + neutral hadrons) to perform exclusive measurements of hadron production at the SPS energy range. • Qualitative step forward in hadron production experiments • Goal: address unsolved issues from ISR era: • Cronin effect • Changeover/interplay soft-hard production • Baryon formation/transfer • Others? SPS has the potential to address many of these issues: wide energy range and choice of beams to narrow down the ‘model space’

  14. Extra slides

  15. Charm production at RHIC PHENIX, PRL 98 (2007) 172301 J. Dunlop, QM09 scc/Ncoll [mb] Remove! pQCD expectation p+p Au+Au Total cross section scales with Ncoll -- as expected

  16. Lowering pT: gluon fragments/bulk response  trigger Long. flow Long. flow d+Au, 200 GeV Au+Au 0-10% STAR preliminary Jet-like peak associated 3 < pt,trigger < 4 GeV pt,assoc. > 2 GeV J. Putschke, M. van Leeuwen, et al `Ridge’: associated yield at large  dN/d approx. independent of  Strong - asymmetry suggests effect of longitudinal flow or underlying event

  17. More medium effects: away-side Mach Cone/Shock wave T. Renk, J. Ruppert Gluon radiation+Sudakov Stöcker, Casseldery-Solana et al A. Polosa, C. Salgado 3.0 < pTtrig < 4.0 GeV/c 1.3 < pTassoc < 1.8 GeV/c Trigger particle Au+Au 0-10% d+Au M. Horner, M. van Leeuwen, et al Medium response (shock wave)or gluon radiation with kinematic constraints? Near side: Enhanced yield in Au+Au consistent with ridge-effect (other proposals exist as well: kT-type effect or Cherenkov radiation) Away-side: Strong broadening in central Au+Au ‘Dip’ at  =  Note also: not shown is large background – something non-trivial may be hiding there?

  18. Dj-correlations from NA49 M. Szuba, QM09

  19. Characterizing the shapes PHENIX M. Szuba, QM09

  20. Summary of correlation shapes M. Szuba, QM09 Away-side shape: no (large) energy dependence Near-side shape: change from ‘dip’ to peak

More Related