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QCD 与强子物理研讨会, 2010 年 8 月 4 - 10 日,威海 Prospects of Flavor Physics at the LHC. 高原宁 清华大学高能物理研究中心. Outline (very selective view of the field). Early results from the LHC experiments LHC as a B factory Remarks on flavor physics Status and prospects - CKM matrix - B s mixing
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QCD 与强子物理研讨会, 2010年8月4-10日,威海Prospects of Flavor Physics at the LHC 高原宁 清华大学高能物理研究中心 Y. Gao, Prospects of flavor physics at the LHC
Outline(very selective view of the field) Early results from the LHC experiments LHC as a B factory Remarks on flavor physics Status and prospects - CKM matrix - Bs mixing - Rare decays Conclusion Y. Gao, Prospects of flavor physics at the LHC
LHC is running… LHCb operation ~400 nb-1/experiment delivered to ATLAS, CMS , LHCb Date collected with high efficiencies (> 90%) Much more underway… Y. Gao, Prospects of flavor physics at the LHC
Quarkonia production Signals seen from data ! Y. Gao, Prospects of flavor physics at the LHC
Quarkonia production CMS preliminary : (4≤pT≤30GeV/c and |y| <2.4) BR(J/ψ→µ+µ−)·σ(pp→J/ψ + X) = (289.1 ± 16.7(stat) ± 60.1(syst)) nb LHCb preliminary : (pT≤10GeV/c and 2.5<y <4) σ(pp→J/ψ + X) = (7.65 ± 0.19(stat) ± 1.10(syst) +0.87-1.27 ) b Data favor neither color singlet nor color octet model. J/ in central region J/ in forward region Y. Gao, Prospects of flavor physics at the LHC
Quarkonia production • σ(pp →Υ(1S)X)·B(Υ(1S)→µ+ µ−)=(8.3±0.5±0.9±1.0)nb • (Assuming no polarization and integrated over |y| <2.0) U(1s, 2s and 3s)→μ+μ- Y. Gao, Prospects of flavor physics at the LHC
- bb cross-section - CMS preliminary : (4≤pT≤30GeV/c and |y| <2.4) BR(J/ψ→µ+µ−)· σ(pp→bX→ J/ψX’) = (56.1 ± 5.5(stat) ± 7.2(syst) )nb - LHCb preliminary : (pT≤10GeV/c and 2.5<y <4) σ(pp→ bX→ J/ψX’) = (0.81 ± 0.06(stat) ± 0.13(syst) ) b bb in central region bb in forward region Y. Gao, Prospects of flavor physics at the LHC
- bb cross-section - bb cross-section from BD0X, with D0 K - correlate D0 with of right (wrong) sign Y. Gao, Prospects of flavor physics at the LHC
Fully reconstructed B events Y. Gao, Prospects of flavor physics at the LHC
Flavor physics at hadron colliders Tracking • We need good Vertexing Particle Identification
Flavor program at LHC • LHC is also a b-factory • Next generation of flavor program • 40% Bu , 40% Bd, 10% Bs, 10% b-baryons Bs is very hard at (Super-)B factories, but may be crucial for NP…
LHCb Experiment It is not very easy to realize MFV in theoretical models
Tracking at ATLAS, CMS and LHCb It is not very easy to realize MFV in theoretical models
Hadron ID It is not very easy to realize MFV in theoretical models
Remarks on flavor physics • It is not easy to reconcile the 2 points: • - The SM is very successful in describing quark mixing • - New physics TeV Y. Gao, Prospects of flavor physics at the LHC
Minimal Flavor Violation (MFV) • In the Standard Model • MFV Hypothesis • Yukawa coupling is unique source of flavor symmetry breaking also beyond the SM • It is not very easy to realize MFV in theoretical models Y. Gao, Prospects of flavor physics at the LHC
CKM Matrix At first sight the global CKM fit shows an excellent consistency. Y. Gao, Prospects of flavor physics at the LHC
CKM Matrix Closer inspection shows some tensions … Y. Gao, Prospects of flavor physics at the LHC
CKM Matrix The sin2 & Br(B) tension: closer look Y. Gao, Prospects of flavor physics at the LHC
CKM Matrix LHCb will measure in trees and loops Y. Gao, Prospects of flavor physics at the LHC
Bs mixing Recent results from CDF & D0 - Bs J/ : 2.1 sigma -> 1.0 sigma -> measures sin2s - D0 observed a 3.2 sigma anomalous in like-sign dimuon charge asymmetry Y. Gao, Prospects of flavor physics at the LHC
Bs mixing At LHCb, PID may help event selection and flavor tagging Y. Gao, Prospects of flavor physics at the LHC
Bs mixing Prospects Y. Gao, Prospects of flavor physics at the LHC
Bs,d →μ+μ− Very small in SM, could be enhanced, e.g. in MSSM Current CDF (World’s best) limit Y. Gao, Prospects of flavor physics at the LHC
Bs,d →μ+μ− at LHCb Ways to enhance S/B - Vertexing - Invariant mass - Muon ID Using control samples So far data consistent with MC background predictions Y. Gao, Prospects of flavor physics at the LHC
Bs →μ+μ− at LHCb LHCb roadmap c.f. MC studies at 14 TeV Y. Gao, Prospects of flavor physics at the LHC
B K* +- Y. Gao, Prospects of flavor physics at the LHC
B K* +- Y. Gao, Prospects of flavor physics at the LHC
B K* +- • Measurements seem favor • LHCb sensitivity: • 0.1 fb-1 ~ B Factories • 1.0 fb-1 ~ 4 sigma exclusion of SM • (Assuming Belle central value) Y. Gao, Prospects of flavor physics at the LHC
Conclusion • Flavor programs at LHC (and Super B Factories) will provide further precise measurements on CKM matrix elements, (very) rare decay rates which are sensitive to new physics beyond the Standard Model. • Theory – Experiment interplay is essential to maximize the potential of these (expensive) programs. • Complementary to experiments at high energy frontier, flavor physics will help us to explore features of the new physics, hopefully in near future.