1 / 17

Heavy flavour capabilities with the ALICE TRD

Heavy flavour capabilities with the ALICE TRD. Benjamin Dönigus 20.09.2008 ISNP 2008 Erice/Sicily. Outline. Motivation The ALICE experiment at the LHC Heavy flavoured mesons Quarkonia Open beauty Heavy flavoured baryons Conclusion. Physics Motivation.

derekphillips
Download Presentation

Heavy flavour capabilities with the ALICE TRD

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. Heavy flavour capabilities with the ALICE TRD Benjamin Dönigus 20.09.2008 ISNP 2008 Erice/Sicily

  2. Outline • Motivation • The ALICE experiment at the LHC • Heavy flavoured mesons • Quarkonia • Open beauty • Heavy flavoured baryons • Conclusion

  3. Physics Motivation • Charm and beauty quarks have heavy mass composition through the coupling to Higgs field • In QGP where the chiral symmetry might be restored, charm and beauty quarks remains heavy • Charm and beauty are a good probe for the medium The measurement of charm/beauty cross section allows: • Test of pQCD (scales mF, mR) • Probe parton distributions • Probe heavy-quark energy loss • Baseline for J/y (U)enhancement (suppression) in Pb + Pb[1] X. Zhu, M. Bleicher, K. Schweda, H. Stöcker, N. Xu et al., PLB 647 (2007) 366. [1] P. Braun-Munzinger and J. Stachel, Nature 448(2007)302

  4. Production cross sections c(LHC) = c(RHIC) × 25 b(LHC) = b(RHIC) × 100 jet(LHC) = jet(RHIC) x 10 5 K. Safarik, CERN, Geneva

  5. Production of cc & bb pairs in different LHC running modes Most c-quarks emerge in D-mesons, a good fraction in Lc baryons, e.g. in every HI collision around 7 D s and 1 Lc is created in the acceptance J c Ds 0 Most b-quarks emerge in B-mesons, significant fraction in Lb baryons D D0 Statistics plot: H. Yang and Y. Wang 5 ALICE Collaboration et al 2006 J. Phys. G: Nucl. Part. Phys.32 1295-2040

  6. ALICE A Large Ion Collider Experiment • 1000 physicists • 31 countries • 109 institutes Size: 16 x 26 meters Weight: 10,000 tonnes

  7. Particle Identification in ALICE • ‘stable’ hadrons (π, K, p): 100 MeV/c < p < 5 GeV/c; (π and p with ~ 80 % purity to ~ 60 GeV/c) • dE/dx in silicon (ITS) and gas (TPC) + time-of-flight (TOF) + Cherenkov (RICH) • decay topologies (K0, K+, K-, L, D) • K and L decays beyond 10 GeV/c • leptons (e,μ ), photons, π0 • electrons TRD: p > 1 GeV/c, muons: p > 5 GeV/c, π0 in PHOS: 1 < p < 80 GeV/c • excellent particle ID up to ~ 50 to 60 GeV/c

  8. electron ID in central barrel p>1 GeV/c fast trigger for high momentum particles (hadrons, electrons) within ~6 ms ALICE TRD Transition Radiation Detector (TRD) • 540 detectors ~ 760m2 • 18 supermodules • length: 7m • X/X0 ~ 22 % • 28 m3 Xe/CO2 (85/15) • 1.2 million readout channels SM00 SM08 4/18 supermodules installed will be completed for the first heavy ion run 2010 SM17 SM09

  9. TRD PID Definition: Fraction of particles wrongly identified as electrons @ 90% electron efficiency A. Bercuci, GSI, Darmstadt & A. Wilk, IKP, Münster

  10. Quarkonia • Signal from quarkonia • For PbPb collisions at • 5.5 TeV per nucleon pair • 1 year statistics • 2x10 events • 10 % central • pt > 1 GeV/c • Measure the yield of J/Y, Y´ and the U family 8 W.Sommer, IKF, Frankfurt

  11. rec. track e Open beauty Primary Vertex B X d0 • B → e + X • Branching Ratio= 21% • 11% from b → B → e+X • 10% from b → B → D → e+X ct (D0)~123 mm ct (B) ~500 mm Electron Identification (TPC+TRD) (separation between e/p) Kinematical Cuts (in d0 according to the pt bin) ALICE Collaboration et al 2006 J. Phys. G: Nucl. Part. Phys.32 1295-2040

  12. Heavy flavoured baryons • The baryon/meson ratio measured at RHIC showed an anomalous enhancement for lighter quarks. • Measurements also showed that at RHIC the heavy quark quenching is stronger than in theoretical predictions as seen in the RAA for non-photonic electrons. G. Martínez-García et al 2008 J. Phys. G: Nucl. Part. Phys.35 044023

  13. Lb Lc e ne with Lc  p p K - + Lb is the simplest baryon which contains a beauty quark and has a semileptonic decay into Lce n of 5% branching ratio Lb & Lc have up to now not be measured at heavy ion collisions - - Trigger p+ p Lb = udb K- e- Lc = udc Lc+ Decay Vertex 1 Decay Vertex 2 60 mm ct =60 mm Lb0 ct =369 mm 369 mm nl Primary Vertex 13

  14. CDF results for Lb + + • Detect Lc K p p and m • nm carries the missing mass/energy •  very broad distribution (~ 2 GeV) •  fits MC expectations • 173 pb (April 2006 – September 2007) • m Trigger used (pt > 2 GeV/c) -1 14 CDF note 7635

  15. Pythia results for Lb Lc e n - Reconstruction of the invariant mass without the anti-neutrino leads to a similar distribution as measured at CDF  Study e-Trigger with TRD

  16. Conclusion • ALICE is a general purpose heavy ion experiment which will help • to understand matter under extreme conditions • The ALICE TRD will provide a good electron identification and • a electron trigger for pt > 3 GeV/c • Heavy-quark hadrons carry unique information on QCD-medium  properties created at the LHC • TRD will help to identify electrons from heavy-quark decays

  17. Thank you!

More Related