PWG-DQ - Physics plans for 2012 Dileptons and quarkonia

5 Physics Analysis Groups (from low to high invariant masses) LMee (Low mass dielectrons) LMmumu (Low mass dimuons) Jpsi2ee (J/ ee) Jpsi2mumu (J/ ) Upsilon2mumu ( )

For each group First plots, where available, on analysis developments (especially from Pb2011) Plans for preliminary results (Hard Probes, Quark Matter) Need for productions Manpower Critical items

LMmumu (A. DeFalco, R. Tieulent) Main items for 2012

pp at 2.76 TeV Results almost finalized for the Integrated and pT-differential cross sections extracted (pT>1 GeV) Now trying to optimize selections to recover lower-pT region Reminder: pp at 7 TeV paper submitted to PLB (arXiv:1112.2222)

PbPb, 2011 data Larger statistics with respect to 2010 However, unfavorable pT threshold (1 GeV/c) for the bulk of the data, taken with a dimuon trigger Use central and semi-central trigger sample

Some plots to give a flavor of what can be expected…..

LMmumu - selected plotsPbPb2011

Combinatorial background subtractionCompare like-sign with mixed events under control to ~1% level

LMmumu - selected plots

Compare opposite sign with background calculated through mixed and LS Some hints for / and in some bins after background subtraction Problem

S/B ~ 10-2 for central events need to understand background to 10-3 level

LMmumu - plans Manpower: 2PhD + 1 post-doc + 5 senior (not full time)

pp at 2.76 TeV : finalize in spring, before Hard Probes RAA for low-mass hadrons: expected for Quark Matter

MC productions: no defined plan for the moment, start with short local productions, official requests to come later

Critical item: background subtraction

(C. Baumann, T. Gunji)

JPsi2mumu (R. Arnaldi, C. Suire) Main items for 2012

Completion of papers under development (mainly editorial work) Pb-Pb RAA pp at 2.76 TeV J/ yield vs multiplicity in pp

PbPb, 2011 data Larger statistics with respect to 2010 (~factor 20) J/ RAA differential in pT and centrality J/ elliptic flow Polarization (2S)

Several plots from Pb2011 already available…..

pp, 2011 data (2S) Larger pT coverage for cross sections and polarization

Higherpriority

JPsi2mumu - plots

Dimuon trigger(bulk of the statistics)

Minimum biasCentralSemi-central

L. Valencia

R. Arnaldi

JPsi2mumu – selected plots Preliminary investigations of RAA vs centrality and pT Warning: normalization still relies on 2010…..

…still, the compatibility of the shapes is already good news More work ahead on acceptances and normalization

R. Arnaldi

JPsi2mumu – selected plots

We have as many high pT J/ as our total 2010 statistics Interesting hints: the “flat” centrality dependence for pT-integrated suppression is no more present at high pT

(quantity proportional to RAA)

L. Valencia

JPsi2mumu – selected plots

centrality

v2 studies are advancing fast!

Event plane method: flattening to be still improved, event plane resolution to be taken into account

Gapped correlation method looks very promising too Developments in collaboration with the FLOW group

H. Yang

JPsi2mumu – selected plots

(2S) visible for the first time in Pb-Pb at the LHC Tough analysis, significance is low

A. Lardeux

JPsi2mumu – plans Manpower: 3PhD + 3 post-doc + 5 senior (not full time)

pp/PbPb papers (2010 data) out to the arXiv in a few weeks RAA differential in pT and centrality: for Hard Probes J/ elliptic flow: try to converge even before Hard Probes to a paper (PRL) Polarization: early to judge between HP and QM (2S): difficult to predict now

MC productions: need soon a production with embedding. Needs still some technical work from the experts

Critical item: none

Intermezzo – p-Pb, Pb-p At the LHC, no knowledge on the nPDFs in the forward region and

large uncertainties in the backward region RHIC uses backward data to constrain σabs, needed for J/ too

3 scenarii under discussion

Scenario 3 has several advantages (same s, possibility of having same x-coverage by properly restricting the analysis domain in y) Might be difficult to implement (J.Jowett)

(see Cynthia presentation on Friday)

(C. Blume, G. Bruno)

A couple of plots on now starting analysis…..

Jpsi2e – selected plots0-10% 20-40% 40-80% 0-20% 20-40% 0-80%

Julian Book, PAG Meeting 09/01/12

Jpsi2e – selected plots

Jens Wiechula, PAG Meeting 19/12/11

Julian Book, PAG Meeting 09/01/12

Background is clearly an issueSeveral methods to attack itTrack rotation, mixed events, fits (high pT), like sign ?

Upsilon2mumu (J. Castillo, D. Das) Main items for 2012

Completion of work on pp 2011 Analysis rather advanced, PC in the next future ?

PbPb, 2011 data RAA (2S+3S)/ (1S) (a la CMS) Two centrality bins ?

Plots from ongoing analysis (pp and PbPb)…..

Alignment, fundamental issue Refine Boff alignment Use GMS in the reconstruction Move to Bon alignment

Crash programfor the next month

Upsilon2mumu – selected plots

From J/ and /(J/)

Luminosity from trigger counters

Work still in progress butprospects are good

X. Lopez

Upsilon2mumu – plots

Signal finally (well) visiblealso in PbPb

First try fitting with the variousresonances with relative yieldsas free parameters

A. Lardeux

R. Arnaldi

Upsilon2mumu (alignment) – plotsChamber resolution(bending plane)Use of GMS does not bring the expectedimprovement

Design resolution100 m

Bias suspected in the Boff procedure. Now investigating

Upsilon2mumu – plans

Manpower: 2 PhD, 2 postdoc FTE (+3 staff) Enough for pp, more people to join PbPb effort

pp results: analysis ongoing (look at LHC11e), aim for a paper in the next months RAA and resonance ratios: need better alignment and to work out a suitable pp reference (no 2.76 TeV)

MC productions: production with embedding. Could be done together with the J/ (depending on alignment timescales) Critical item: alignment !

Improvement of resolution to 120-130 MeV looks realistic (difficult to push to nominal 100 MeV value) Crash program organized (more news in ~1 month) Arrive in time for Pb-Pb pass3

Conclusions

Activity starting in all the groups for the analysis of 2011 Pb (in addition to paper preparation and p-p issues)

Expect a wealth of new results already for Hard Probes

Some critical items are in our path, special attention (and manpower) on them