Reddy Pratap Gandrajula (University of Iowa) on behalf of CMS Measurement of 𝝈 𝑩 𝒄 ± ×𝑩𝒓 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝝈 𝑩 ± ×𝑩𝒓 𝑩 ± → 𝑱 𝝍 𝑲 ± and 𝑩𝒓 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝝅 ± 𝝅 ∓ 𝑩𝒓 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± at 𝑺 =𝟕 𝑻𝒆𝑽 Reddy Pratap Gandrajula (University of Iowa) on behalf of CMS Analysis referance:BPH-12-011 4/8/2014 APS April meeting 2014

𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± , 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝝅 ± 𝝅 ∓ , and 𝑩 ± → 𝑱 𝝍 𝑲 ± signals Outline Introduction CMS detector Analysis Strategy 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± , 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝝅 ± 𝝅 ∓ , and 𝑩 ± → 𝑱 𝝍 𝑲 ± signals Results Summary and Conclusions 4/8/2014 APS April meeting 2014

Introduction LHC opened a new era for the flavor physics by copiously producing heavy flavors at 7 and 8 TeV. One particle which deserves careful study is the 𝐵 𝑐 meson, whose small cross-section has limited, so far, its experimental investigation. A rich program of measurements is being carried out by LHCb at 2<η<5; the complementary pseudorapidity region can be accessed by CMS 4/8/2014 APS April meeting 2014

Introduction…. CMS, with excellent muon identification system and tracker detectors, allows for 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± and 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝝅 ± 𝝅 ∓ final state studies in a central 𝜂 region. Measurements, driven by the 𝑱 𝝍 in the final state provides basic information about the 𝑩 𝒄 ± meson, which serve an introduction for further experimental investigation. 𝑢 𝑢 𝜋 + 𝜋 + 𝑑 𝑑 𝑏 𝑏 𝐵 𝑐 + 𝑐 𝑱 𝝍 𝐵 𝑐 + 𝑐 𝑐 𝑐 𝑐 𝑱 𝝍 𝑐 g g 𝑑 𝜋 − 𝑢 𝑑 𝜋 + 𝑢 4/8/2014 APS April meeting 2014

Good performance from LHC & CMS CMS & LHC Good performance from LHC & CMS Identifies and measures 𝑒, 𝜇, 𝛾, charged particles, Jets, etc. In 2011 it collected 5.56 𝑓𝑏 −1 pp data. Analysis is performed on 5.1 𝑓𝑏 −1 data. 4/8/2014 APS April meeting 2014

Most important sub-detector elements for this analysis Slice view of CMS Most important sub-detector elements for this analysis 4/8/2014 APS April meeting 2014

Analysis Strategy The analysis is driven by 𝑱 𝝍 reconstruction: Two oppositely – charged muons selected with the standard muon selection. All triggers apply the following cuts: cos 𝛼 >0.9 , where 𝛼 is the pointing angle, in the transverse plane, between the dimuon momentum and the direction from the dimuon vertex to the beam spot. 𝐿 𝑥𝑦 𝜎 𝑥𝑦 >3, where 𝐿 𝑥𝑦 is the transverse detachment between the dimuon vertex and the beamspot and 𝜎 𝑥𝑦 is the corresponding uncertainty. 𝑝 𝑇 𝜇𝜇 >6.9 𝐺𝑒𝑉 Dimuon vertex probability 𝑃 𝑉𝑇𝑋 >0.5% Distance of closest approach between the two muons < 0.5 cm. 4/8/2014 APS April meeting 2014

The cuts were tightened with increasing instant.Lumi. Analysis Strategy… The cuts were tightened with increasing instant.Lumi. 𝑝 𝑇 𝜇 >4.0 𝐺𝑒𝑉, |𝜂| 𝜇 <2.2, Dimuon vertex probability 𝑃 𝑉𝑇𝑋 >15% Dimuon trigger matched 𝑑𝑖𝑚𝑢𝑜𝑛 𝑜𝑛𝑙𝑖𝑛𝑒 𝑜𝑓𝑓𝑙𝑖𝑛𝑒 ∆𝑅<0.5 𝐵 𝑐 + → 𝐽 𝜓 𝜋 + 𝐵 𝑐 + → 𝐽 𝜓 𝐾 + candidates: 𝐽 𝜓 with 1 track, assuming that is a pion (kaon) 𝐵 𝑐 + → 𝐽 𝜓 𝜋 + 𝜋 + 𝜋 − candidates: 𝐽 𝜓 with 3 tracks, assuming that they are pions. primary vertex secondary 𝐵 (𝑐) + 𝐾 + 𝜋 + primary vertex secondary 𝐵 𝑐 + 𝜋 − 𝜋 + 4/8/2014 APS April meeting 2014

Analysis Strategy….. The pion(kaon) candidates are required to have: a track fit (𝜒 2 𝑛𝑑𝑜𝑓 )<3 Tracker hits>6, pixel hits ≥2, 𝜂 <2.4 and 𝑝 𝑇 >0.9 𝐺𝑒𝑉 𝑐 . 𝐿 3𝐷 𝜋 ± , 𝑱 𝝍 𝜎 3𝐷 <6 (Inferred from MC). Δ𝑅 𝑱 𝝍 , 𝜋 𝐾 <2.5 for 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± and 𝐵 ± → 𝑱 𝝍 𝑲 ± In 𝑩 𝒄 + → 𝑱 𝝍 𝝅 + 𝝅 + 𝝅 − analysis, Δ𝑅<1 is required for the highest 𝑝 𝑇 track, while Δ𝑅<1.6 is required for the other two pions. 𝑩 𝒄 + Vertex probability >0.1%; 𝑝 𝑇 ( 𝑱 𝝍 )>7.1 𝐺𝑒𝑉 𝑐 . In case of multiple 𝑩 𝒄 ± ( 𝐵 ± ) candidates, the one with highest 𝑝 𝑇 is retained. 4/8/2014 APS April meeting 2014

Requirements for 𝑩 𝒄 + reconstruction and Cut optimization using 𝑺 𝑺+𝑩 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝝅 ± 𝝅 ∓ 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± and 𝑩 ± → 𝑱 𝝍 𝑲 ± 𝑝 𝑇 𝐵 𝑐 >15GeV/c; 𝑦 𝐵 𝑐 <1.6; 𝐵 𝑐 Vertex CL>20%; cos 𝜃 >0.99; 𝑝 𝑇 𝜋 1 >2.5GeV/c; 𝑝 𝑇 𝜋 2 >1.7GeV/c; 𝑝 𝑇 𝜋 3 >0.9GeV/c; Δ𝑅 𝑱 𝝍 , 𝜋 𝑠 <0.5 where Δ𝑅 is taken from Δ𝜂 and Δ𝜙 derived from the 𝑱 𝝍 momentum vector and the sum of the momentum vectors of the three pions 𝜋 𝑠 . 𝑝 𝑇 𝐵 𝑐 >15GeV/c; 𝑦 𝐵 𝑐 <1.6; 𝐵 𝑐 Vertex CL>6%; cos 𝜃 >0.9; 𝑝 𝑇 𝜋 >2.7GeV/c; Δ𝑅 𝑱 𝝍 ,𝜋 <1. 4/8/2014 APS April meeting 2014

𝑩 𝒄 + and 𝑩 + mass fits 𝑩 𝒄 ± Signals modeled to a Gaussian fit, 𝑩 + signal to a double Gaussian fit and background is modeled to 2nd order Chebyshev polynomial. 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝝅 ± 𝝅 ∓ yield:92±27; m:6.266±0.006 𝐺𝑒𝑉 𝑐 2 𝑩 𝒄 + → 𝑱 𝝍 𝝅 + yield:176±19; m:6.267±0.003 𝐺𝑒𝑉 𝑐 2 𝑩 + → 𝑱 𝝍 𝑲 + yield:90398±357; m: 5.27847±0.00007 𝐺𝑒𝑉 𝑐 2 Bkg 𝑩 𝒄 ± → 𝑱 𝝍 𝑲 ± 𝑲 ∓ 𝝅 ± negligible Bkg 𝑩 𝒄 ± → 𝑱 𝝍 𝑲 ± negligible Bkg 𝑩 ± → 𝑱 𝝍 𝝅 ± negligible 4/8/2014 APS April meeting 2014

The ratio 𝝈 𝑩 𝒄 ± ×𝑩𝒓 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝝈 𝑩 ± ×𝑩𝒓 𝑩 ± → 𝑱 𝝍 𝑲 ± measurement The ratio can be obtained through the relation: 𝑵 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝑵 𝑩 ± → 𝑱 𝝍 𝑲 ± = 𝝈 𝑩 𝒄 ± ×𝑩𝒓 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± × 𝝐 𝑩 𝒄 ± 𝝈 𝑩 ± ×𝑩𝒓 𝑩 ± → 𝑱 𝝍 𝑲 ± × 𝝐 𝑩 ± , Where N is the number of signal events and 𝜖 𝑩 (𝒄) ± is the overall analysis efficiency for the 𝑩 ± and 𝑩 𝒄 ± reconstruction. Pt dependent efficiency from MC - BCVEGPY for 𝑩 𝒄 ± and PYTHIA for 𝑩 ± Data are corrected event-by-event according to their 𝑝 𝑡 and related MC efficiency. The efficiency corrected mass plots for 𝑱 𝝍 𝝅 ± and 𝑱 𝝍 𝐾 ± are shown here. 4/8/2014 APS April meeting 2014

Substructure Study & Efficiency Parameterization Data shows some hints of 𝑎 1 ± 1260𝑀𝑒𝑉 and 𝜌 0 770𝑀𝑒𝑉 resonances; but the 𝑩 𝒄 ± yield (about 100) is too small to perform a detailed Dalitz analysis. 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝝅 ± 𝝅 ∓ (Dalitz plot representation of five-body decay of a spinless particle) can be described in its center of mass by mass-combinations: 𝑚 2 𝜇 + 𝜋 + 𝑙𝑜𝑤 , 𝑚 2 𝜋 + 𝜋 − ℎ𝑖𝑔ℎ , 𝑚 2 𝜇 + 𝜋 − , 𝑚 2 𝜋 + 𝜋 + , 𝑚 2 𝜇 − 𝜋 + 𝑙𝑜𝑤 , 𝑚 2 𝜇 − 𝜋 + ℎ𝑖𝑔ℎ and 𝑚 2 𝜇 − 𝜋 − ; the 𝑙𝑜𝑤 and ℎ𝑖𝑔ℎ subscripts refers to the lower and higher invariant mass combination where 𝜋 + is involved. 𝝐=| 𝒑 𝟎 + 𝒑 𝟏 .𝒙+ 𝒑 𝟐 .𝒚+ 𝒑 𝟑 .𝒛+ 𝒑 𝟒 .𝒘+ 𝒑 𝟓 .𝒓+ 𝒑 𝟔 .𝒕+ 𝒑 𝟕 .𝒔| Where x= 𝑚 2 𝜇 + 𝜋 + 𝑙𝑜𝑤 , y= 𝑚 2 𝜋 + 𝜋 − ℎ𝑖𝑔ℎ , 𝑧=𝑚 2 𝜇 + 𝜋 − , w= 𝑚 2 𝜋 + 𝜋 + , r= 𝑚 2 𝜇 − 𝜋 + 𝑙𝑜𝑤 , t= 𝑚 2 𝜇 − 𝜋 + ℎ𝑖𝑔ℎ , s= 𝑚 2 𝜇 − 𝜋 − ; and 𝑝 𝑖 are the free parameters in the 7th dimensional space. The resulting efficiency function is used to weight the data event by event. The efficiency – corrected an unbinned maximum Likelihood fit on data is shown here. 4/8/2014 APS April meeting 2014

Systematics The 𝜎 𝑩 𝒄 ± ×𝐵𝑟 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝜎 𝑩 ± ×𝐵𝑟 𝑩 ± → 𝑱 𝝍 𝑲 ± Systematic uncertainty The 𝐵𝑟 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝝅 ± 𝝅 ∓ 𝐵𝑟 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± Systematic uncertainty Split data sample: three triggered periods, pileup samples(1≤𝑃𝑉≤6 and 𝑃𝑉≥7). Fit variant: Default signal fit a single Gaussian, for syst. Study fit signal to a double Gaussian with widths fixed to MC values, and for bkg by a different order Chebyshev polynomial or exp. function. MC finite size: MC reweighted 𝑌 𝑩 𝒄 ± and 𝑌 𝐵 ± evaluated through pseudo- experiment studies. Efficiency binning: Various bin values are tested for both 𝑩 𝒄 ± and 𝐵 ± Split data sample: No triggered periods(limit stat), pileup samples(1≤𝑃𝑉≤6 and 𝑃𝑉≥7). Fit variant: No variant w.r.t. signal shape(limit stat) and for bkg by a different order Chebyshev polynomial( from 1st to 3rd ). MC finite size: MC reweighted 𝑌 𝑩 𝒄 ± evaluated through pseudo- experiment studies. Efficiency binning: Various bin values are tested for 𝑩 𝒄 ± . Tracking efficiency: efficiency tracking uncertainty for each pion track of 3.9%. Big. Syst Big. Syst 4/8/2014 APS April meeting 2014

Results:In a rapidity region complementary to LHCb 𝝈 𝑩 𝒄 ± ×𝑩𝒓 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝝈 𝑩 ± ×𝑩𝒓 𝑩 ± → 𝑱 𝝍 𝑲 ± = 𝟎.𝟒𝟖±𝟎.𝟎𝟓 𝒔𝒕𝒂𝒕 ±𝟎.𝟎𝟒 𝒔𝒚𝒔𝒕 𝝉 𝑩 𝒄 × 𝟏𝟎 −𝟐 𝑩𝒓 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝝅 ± 𝝅 ∓ 𝑩𝒓 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± =2.43±𝟎.𝟕𝟔 𝒔𝒕𝒂𝒕 (𝒔𝒚𝒔𝒕) +0.05 -0.03 +0.46 -0.44 4/8/2014 APS April meeting 2014

Summary and conclusions The analysis of 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± and 𝑩 ± → 𝑱 𝝍 𝑲 ± is presented CMS 7 TeV data permitted the measurement of the ratio: 𝜎 𝑩 𝒄 ± ×𝐵𝑟 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝜎 𝑩 ± ×𝐵𝑟 𝑩 ± → 𝑱 𝝍 𝑲 ± in a region complementary to that investigated by LHCb collaboration. The analysis of 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝝅 ± 𝝅 ∓ also permitted the determination of the ratio: 𝐵𝑟 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± 𝝅 ± 𝝅 ∓ 𝐵𝑟 𝑩 𝒄 ± → 𝑱 𝝍 𝝅 ± Our results are in agreement with LHCb ones. 4/8/2014 APS April meeting 2014

Questions ? 4/8/2014 APS April meeting 2014

CMS standard soft Muon selection Muon track should have at least 1 pixel hit and at least 5 silicon hits. the normalized c2 of muon track < 1.8. | 𝑑 𝑥𝑦 | < 3.0 cm. | 𝑑 𝑧 | < 30.0 cm. Tracker track matched with at least one muon segment (in any station) in both X and Y coordinates and arbitrated. Triggers and Data Set: Data Set: /MuOnia/Run2011A-08Nov2011-v1/AOD, /MuOnia/Run2011B-19Nov2011-v1/AOD Unprescaled displaced vertex dimuon triggers are considered HLT paths and Luminosity for the signal samples: 4/8/2014 APS April meeting 2014