Quarikonia Study

1. Motivation of Quarkonia (qqbar -> +mu -mu, J/psi, Upsilon family) Study at CMS (Fig. 1)

- Quarkonia's step-wise suppression at high pt region is the one of most direct probes of QGP (Quark-gluon-plasma)

- J/Psi's suppression is already observed in SPS and RHIC.

- So, how about it in CMS ? (there could be more huge suppression or enhanced regeneration ?) and how about Upsilon ?

What is more benefits of CMS than other experiments ?

- Increased energy : 5.5 TeV? (PbPb? collision) - 30 times more huge than RHIC (200 GeV? : AuAu?)

- It can make plasma hotter, longer-lived than RHIC (it can be easy to dissolute the particles which has large binding energy)

- provide good circumstances to produce Quarkonia highly

- high luminosities : 5*10^26 cm^-2 s^-1 (increase events rate)

- high gluon density at low-x, (the almost particles of heavy-flavor quarks is made by gluon-gluon fusion)

- New possibility of Upsilon family (Y, Y', Y'')

2. Quarkonia Generation with HYJET

2nd HYDJET production information

* decache location : /pnfs/cmsaf.mit.edu/t2bat/cms/store/user/davidlw/HYDJET_GEN_X2_MB_4.0TeV/HYDJET_GEN_X2_MB_4.0TeV/545444c24aba01a433ce34e4c379212c/

* 100k production by Wei, including more quarkonia

Analysis of quarkonia with CMSSW at CMSSW_2_1_x

- use 'HydQuarkoniaAnalyzer.cc'

1) pT distributions of J/psis

- the flat around 5 -10 GeV?/c doesn't feed down. This unexpected effect seems to be caused by the cases that the mother is J/psis themselves, chi_cs and color octet state. It is neccessary to check generation situation.

Mothers of J/psi

Mother (id) Number of production Status of Mother Status of J/psi Comment
None 20 21 21
J/psi (443) 3997 21 11  
B0(+-511) 3141(3102) 11 or 12 11  
B+(+-521) 3159(2932) 11 11  
Bs0(+-531) 886(886) 11 11  
B_c(+-541) 27(21) 11 11  
chi_1c(20443) 3855 11 11  
chi_2c(445) 409 11 11  
chi_0c(10441) 17 11 11  
Lambda_b0(+-5122) 618(579) 11 11  
Xi_b-(+-5132) 23(19) 11 11  
Omega_b-(5332) 1 11 11  
Cluster(91) 328 11 11 cluster fragmention (pQCD)
cc~(9900443) 3380 11 11 Color Octet system
cc~(9910441) 336 11 11 Color Octet system
cc~(9900441) 261 11 11 Color Octet system

- pT distribution of Upsilon from 100k hydjet minbias event.

Mothers of Upsilon

Mother (id) Number of production Status of Mother Status of J/psi Comment
None 34 21 21
Upsilon (553) 435 21 11  
Chi_0b (10551) 8 11 11  
Chi_1b (20553) 102 11 11  
Chi_2b (555) 81 11 11  
bb bar 1s (9900551) 32 11 11 Color Octet system
bb bar 3s (9900553) 364 11 11 Color Octet system
bb bar 3p (9910551) 5 11 11 Color Octet system
Cluster (91) 328 11 11 cluster fragmention (pQCD)

2) pT distributions of muons from Kaons, B meson and J/psis

3) Dimuon mass continuum with muon combination

- use 'MuonCombiAnalyzer.cc' - in order to look into clear signal, the study was done separately 0-1 GeV?/c^2, 2 - 4 GeV?/c^2, 0 - 10 GeV?/c^2.

Mass range 0 - 10 GeV?/c^2

Mass range 0 - 1 GeV?/c^2

Mass range 2 - 4 GeV?/c^2

-- DongHoMoon - 27 Apr 2009

Topic attachments
I Attachment History Action Size Date Who Comment
JPEGjpg Fig01.jpg r1 manage 46.4 K 2009-04-29 - 13:12 UnknownUser  
PNGpng Jpsi_From_mother.png r1 manage 23.1 K 2009-04-29 - 13:39 UnknownUser  
PNGpng Muons_and_kaons_BtoJpsi.png r1 manage 18.9 K 2009-04-29 - 13:40 UnknownUser  
PNGpng UpsilonFromMother2.png r1 manage 16.7 K 2009-05-04 - 21:27 UnknownUser  
PNGpng muon_combination_0_10.png r1 manage 14.0 K 2009-04-29 - 15:24 UnknownUser  
PNGpng muon_combination_0_1_Gev.png r1 manage 17.5 K 2009-04-29 - 15:25 UnknownUser  
PNGpng muon_combination_2_4_Gev.png r1 manage 15.9 K 2009-04-29 - 16:43 UnknownUser  
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Topic revision: r3 - 2009-05-04 - DongHoMoon
 
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