Azimuthal angular correlations between heavy flavour decay electrons and charged hadrons in pp collisions at s = 2.76 TeV in ALICE

Transcription

1 Azimuhal angular corrlaions bwn havy flavour dcay lcrons and chargd hadrons in pp collisions a s = 2.76 TV in ALICE DEEPA THOMAS FOR THE ALICE COLLABORATION INTERNATIONAL SCHOOL OF SUBNUCLEAR PHYSICS ERICE, 23 JUNE 2 JULY 22

2 Moivaion High nrgy havy ion physics sudy of phas ransiion of nuclar mar o dconfind srongly inracing QCD mar Quark Gluon Plasma(QGP) Enrgy loss of parons - snsiiv prob of QGP Havy quarks ar producd by hard scaring procss in arly sag of collisions and ravrs h mdium, undrgoing inlasic and lasic collisions Highr pnraing powr Dad con ffc gluon radiaion supprssd a θ < m Q /E Q Good s for prurbaiv QCD calculaions in nw nrgy rgim Yu. Dokshizr and D.E. Kharzv, Phys.L. B (2). Armso al. PRD 69 (24) 43 2

3 Moivaion Inracion of havy quarks wih h QCD mdium can b sudid using lcron from smi-lponic dcay of havy flavour msons (D & B). Undrsanding mass dpndn nrgy loss of havy quarks rquirs disnanglmn of - from D & B. Azimuhal angular corrlaion bwn HF lcrons and chargd hadrons can b usd o drmin h rlaiv conribuion of B dcays o HF - Exploi diffrn dcay kinmaics of D and B hadrons. 3

4 Moivaion Th widh of nar-sid corrlaion disribuion is largr for B mson compard o D mson du o diffrn dcay kinmaics. Rlaiv bauy conribuion o HF - yild xracd by fiing Mon Carlo (PYTHIA) mplas (wih dcor simulaion) o daa. Drmin h bauy producion cross scion from h HFE spcra A complmnary analysis mhod o B-agging using displacd vrics. Dcay kinmaics for havy flavour msons (4.5 < p < 5.5 GV/c) T /Enris dn MC : PYTHIA (PERUGIA-) pp s = 2.76 TV D dcay B dcay η <.9 Dcay kinmaics of havy flavour hadrons - D dcay - B dcay Δφ (rad) 4

5 ALICE dcor ALICE - η <.9 (accpanc of cnral barrl dcors) EMCAL TPC ITS Dcors usd for prsn analysis Innr racking sysm Tim projcion chambr Elcromagnic calorimr η <.7 8 < ϕ < 8 5

6 Analysis Sragy Havy flavour dcay lcron (HFE) idnificaion 6

7 Analysis Sragy Havy flavour dcay lcron (HFE) idnificaion Azimuhal angular corrlaion bwn HFE and chargd hadrons 6

8 Analysis Sragy Havy flavour dcay lcron (HFE) idnificaion Azimuhal angular corrlaion bwn HFE and chargd hadrons Dconvolu c and b o Mon Carlo mpla o Fi daa 6

9 Elcron idnificaion E/p K+p π K+p TPC de/dx - <TPC de/dx> ( TPC-dE/dx ) l pp 5/5/22 s=2.76 TV EMCal Triggr Evns Track 3.5<p<4.5 GV/c <.7 Daas: o pp a s = 2.76 TV o EMCal riggrd vns o Saisics : 6.2 x 5 vns Elcron Idnificaion o TPC : -σ < TPC de/dx < 3σ o EMCAL : < E/p <.2 7

10 Non - havy flavour lcron idnificaion Enris 2 Lik-sign Unlik-sign pp 5/5/22 s=2.76 TV EMCal Triggr Evns Track p >2.5 GV/c <.7 Non-havy-flavour lcron o Main sourcs : γ convrsion, π and η Daliz dcays. o Idnifid using + - invarian mass mhod. Invarian mass cu of 5 MV/c 2 applid Efficincy for Non-havy flavour lcron idnificaion - N NHF rco / N NHF ~ 5% Invarian mass () (GV/c ) Rmaining small conaminaion (< %) corrcd. Non-HFE rconsrucion fficincy from simulaions /5/22 pp s=2.76 TV EMCal Triggr Evns < p (GV/c) 7

11 Azimuhal angular corrlaion of havy flavour lcrons and chargd hadrons dn d /N rig Havy Flavour Dcay -h 2.5 < p < 3.5 GV/c MC c-> MC b->, b->c-> Daa Fi MC : PYTHIA + GEANT3 2 /ndf = 7452 dn d /N rig < p < 4.5 GV/c pp s=2.76 TV EMCal Triggr Evns <.7 2 5/5/22 /ndf = dn d /N rig < p < 6 GV/c 2 /ndf =.2384 Chargd hadron slcion p >.3 GV/c η <.9, <ϕ< dn d /N rig (rad) < p < 7.5 GV/c 2 /ndf = (rad) dn d /N rig (rad) < p < GV/c 2 /ndf = (rad) (rad) Fi daa wih MC mpla for bauy and charm (PYTHIA + GEANT3) Fi funcion : Δϕ daa = cons + r b Δϕ B + (-r b )Δϕ D whr r b = from b / ( from b + from c)

12 Fracion of bauy dcay lcrons from b / ( from b + from c) FONLL ALICE ALICE Sysmaic uncrainiy pp s=2.76 TV EMCal Triggr Evns <.7 - L in = 4.6 nb p (GV/c) Main sourc of sysmaics: Elcron idnificaion using TPC and EMCal. Fi rang : (-,) o (-2.5,2.5). Non-HFE idnificaion - invarian mass and de/dx cu. A ~ 5 GV/c h bauy conribuion has similar magniud as charm.

13 Fracion of bauy dcay lcrons from b / ( from b + from c) FONLL ALICE ALICE Sysmaic uncrainiy pp s=2.76 TV EMCal Triggr Evns <.7 - L in = 4.6 nb from b / ( from b + from c) ALICE pp STAR pp PHENIX pp ALICE ALICE Sysmaic uncrainy STAR STAR Sysmaic uncrainy PHENIX PHENIX Sysmaic uncrainy - s=2.76 TV, <.7, L =4.6 nb in - s=2 GV, <.7, L =.95 pb in - s=2 GV, <.35, L =5.99 pb in 9% C.L. 9% C.L p (GV/c) Main sourc of sysmaics: Elcron idnificaion using TPC and EMCal. Fi rang : (-,) o (-2.5,2.5). Non-HFE idnificaion - invarian mass and de/dx cu. A ~ 5 GV/c h bauy conribuion has similar magniud as charm. Consisn wih FONLL pqcd calculaions 3 and RHIC masurmns, p (GV/c) STAR Collaboraion, Phys. Rv. L. 5, 223 (2). 2 PHENIX Collaboraion, Phys. Rv. L. 3, 822, (29). 3 M. Cacciari al., JHEP 3, 6 (2) and priva communicaion (22)

14 Conclusions Rlaiv bauy conribuion o h havy flavour dcay lcron yild is masurd in pp collisions a 2.76 TV wih h ALICE dcor using an EMCal riggr. Bauy conribuion o havy flavour lcron yild is similar o charm conribuion a around 5 GV/c. Bauy fracion is wll dscribd by FONLL pqcd calculaion and i is comparabl o rsuls a 2 GV from RHIC. Oulook: Masurmn of h B dcay lcron cross scion wih Havy Flavour Elcron spcra. Prform his analysis in Pb-Pb collisions a 2.76 TV. 2