1. Xiangwei Meng Institute of High Energy Physics, CAS, Beijing
First Workshop of the CMS Quarkonium Task Force Sep , SUMMARY
Xiangwei Meng
Institute of High Energy Physics, CAS, Beijing
Sep. 25 , 2009
CMS B-physics Group Meeting 08,28,2008

2. CMS B-physics Group Meeting 08,28,2008
Contents
2 days
20 reports
~30 persons
Techniques:
CDF’s experience*
The CMS trigger strategy and quarkonium physics
From T0 to your desktop: the CMS data flow
quality criteria for the global and tracker muons*
Onia event yields vs. luminosity*
Fitting functions for the dimuon mass peaks*
Quarkonia models and event generation; bridges with theory
……..
Physics
From the J/psi to the b harond pt x-section
chi_c and chi_b production
Upsilon->mu mu
Upsilon -> e+e-
J/Psi polarization/Upsilon polarization
tutorial:
luminosity information in the data
run the general tag and probe code
CMS B-physics Group Meeting 08,28,2008

3. Quarkonium Physics at the Tevatron
James Russ
Carnegie Mellon University
theoretical models to try to match vector meson data from Tevatron and HERA
cross section problem  CSM  NRQCD
polarization problems with NRQCD  multi-gluon models
recent considerations: questions about kT factorization approach, Q fragmentation effects at Tevatron
Experimental results:
J/  and (2S) cross section and polarization from CDF
(1S) and (2S) polarization from D0
brand new results on (1S) polarization from CDF
CDF work on new charmonia X(3872) and Y(4140)
J/ Analysis to Handle b-Decay Events
Two approaches
discriminate based on muon miss distance at primary vertex to separate prompt/decay
make joint mass-lifetime fit to identify prompt/decay
CDF has used each to good avail
miss distance analysis is faster
joint fit gives best yield estimate for cross section
CMS B-physics Group Meeting 08,28,2008

4. X(3872) & another New State – Y(4140)
Measure JP at a hadron machine? Yes!
pp mass distribution sensitive to orbital angular momentum in decay and hence to parent’s spin-parity
Top: fit to expected shape for (2S)  (1S)pp (validate)
Bottom: fit to L=0 and L=1 for X(3872)  (1S)pp
The X(3872) tries to decay to J/r … but it’s too light.
Belle observes another threshold J/V state in B decays: Y(3930)  J/ w
CDF used its huge B  J/ X sample to look for a narrow J/ f state near threshold
No good theory for these objects, but interesting experimental pattern.
CMS B-physics Group Meeting 08,28,2008

5. Glob & Trk Muon selection: low pT
David Lopes Pegna
(Princeton University)
Mario Peliccioni
(INFN & University of Torino)
need any cut to clean up the global muons? Yes!
Main background sources from muons from kaon/pion decays (decay-in-flight) and Kaons/pions that reach the muon system (punch-through)
the global muon algorithm is not extremely efficient at low pT
Tracker muons help to recover the low pT part of the muon spectrum
But higher fake rate from punch-through and DIF
Access Chi2/NDF(<10), Nhits(>12) from inner(global) track associated to tracker(global) reco::muon
Additional variables are provided in the external function (in 3_X) bool muon::isGoodMuon( const reco::Muon& muon, muon::SelectionType type )
Trk Muons: Summary of cuts 22X(31X) Arbitration
TM2DCompatibilityLoose
OneStationTight
μ χ2 silicon fit < 1.9
μ inner hits > 11(12)
CMS B-physics Group Meeting 08,28,2008

6. Fitting functions for the dimuon mass peaks
Sara Bolognesi, CERN
Fitting functions for the dimuon mass peaks
a look to the scale and resolution behavior
In the present analyses usually each peak is fit with 2 gaussians(+ background shape linear or exponential) because:
bias in the muon scale can shift the mass peak:
if bias depends on muon η, pT →different shift peak in different kinematic regions
􀂃resolution on the muon pT(→width of dimuon mass peak) changesas a function of muon ηand pT
tracker geometry
material budget
CMS B-physics Group Meeting 08,28,2008

7. Onia event yields vs. luminosity
Zongchang Yang1, Roberto Covarelli2, Fabrizio Palla3
1) University of Tennessee, 2) CERN, 3) INFN Pisa
Onia event yields vs. luminosity
Summer09 TeV MC
samples Nevts(M) X-sec. (mb) Int. Lumi(pb-1)
prompt J/y->m+m (0.809)
B->J/y->m+m
Upsilon(1S)->m+m E-3 55 (0.707)
Pp->m+X (0.939)
~5 pb-1 data are collected before the menu changes
Total ~50 pb-1 data of the 7 TeVcollisions
First cross section measurement at 5 pb-1integral luminosity
–J/psi yields: 0.3 M (global+global), 0.25 M (global+tracker), 0.55 M (global+calo)
–J/psi yeilduncertainties: 0.002, 0.006, 0.009
–Upsilon yields: 16 K, 6 K, 6K
–Upsilon yeilduncertainties: 0.02, 0.08, 0.7
Lower-purity (tracker and calo) muons:
–can be useful for J/ywith single muontrigger before the menu changes
–do not improve the signal in double muontriggers
HLT_DoubleMu0 is a good choice after menu changes
CMS B-physics Group Meeting 08,28,2008

8. Skimming for the Onia studies， 1E31 trig path & new Gen by EvtGen
Skimming should always keep all the useful information for the analysis.
–Filter on two muons with invariant mass cut (>2 GeV/c2)
–Additional cuts on muon qualities: global, tracker and calomuons
–Reduce the event size to 150 KB/evt
–A reasonable total data size
CMS B-physics Group Meeting 08,28,2008