1 / 21

Looking for New Physics: Prospects of B-Physics at LHCb

Discover the prospects of searching for New Physics through B-decays at LHCb, including precision tests of the Standard Model and key measurements like CKM angles. Learn about tree and loop decays, CP asymmetries, and Bs sector exploration.

acardona
Download Presentation

Looking for New Physics: Prospects of B-Physics at LHCb

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. s b Looking for New Physics: Prospects of B-Physics at LHCb Ulrich Uwer Physikalisches Institut Heidelberg On behalf of the LHCb Collaboration

  2. Search for New Physics in B decays New Physics W New Physics W …precision test of the SM at loop level box diagramms penguin amplitudes Deviations from Standard Model: absolute rates and phase dependent CP asymmetries • measurement of  in tree and loop decays • exploring the Bs sector - mixing phase s • bs  penguin transitions • very rare FCNC decays key measurement: Outline

  3. LHCb – Key Properties e (KK) = 88% e (pK) = 3% • High statistics • L ~ 2 x 1032 cm-2 s-1 • ~ 1012 bb events / year (2 fb-1) • 50 kHz bb-events • B±, B0, Bs, Bc, Lb … • Tracking & Vertexing • B Mass resolution: ~ 15…20 MeV • Proper time resolution:~ 40 fs • Particle identification • p/K separation over 2 GeV < p < 100 GeV • Trigger (2 kHz to tape) • “High pT”lepton, photon & hadron 1st level trigger w/ 1 MHz: Example: sin2(B0J/Ks) 0.5 fb-1 52k evts (sin2)=0.020 (2 fb-1) m/e/h/g: 1.1/2.8/3.6/2.6 GeV (sin2)=0.023 (today)

  4. CKM Angle  Indirect Directmeasurement • A lot of pioneering work from B factories • No significant constrain from direct measurements yet Precise determination of  in tree and loop decays.

  5.  from B  DK Tree Decays Tree decays:  fD  fD ADS (Atwood,Dunietz,Soni) method: Common flavour state fD=(K+ p–)Note: D0→K+p–doubly Cabibbo suppr. GLW (Gronau,London,Wyler) method: fD is a CP eigenstate, fD= K+K-, +- sg= 11° – 13° 2 fb-1

  6.  from B  DK Tree Decays GGSZ Method: Use Dalitz decays: 2 fb-1: ~ 5k evts 2 fb-1 Statistical uncertainty sg= 10° Amplitude model sg = 13° Binned fit/Cleo-C data Combined sensitivity sg 2fb-1 LHCb-2008-031 + ??????

  7. Time dependent Asymmetry Tree b->c & b->u decays interfere through Bs mixing Time dependent CP asymmetry: Use BsDs to determine tagging dilution simultaneously 2 fb-1 2 fb-1 Bs→ Ds-K+

  8.  Sensitivity /K /K Bd/s Bd/s /K /K LHCb-2008-031 Tree Level Processes • Combination: • BD0K • B0D0K*0 • Time dependent: B0  Dp Bs  DsK 2o …3o reachable after 5 yr Loop Processes R.Fleischer Measure time dependent CP asymmetries (direct, mixing) in Bd   and Bs KK. Crucial: P/T described by (d, ) 7…10o (2fb-1) ~5o (10 fb-1) Uspin constraint: dpp= dKK 20% • from interference between mixing tree (T) and penguin (P) amplitudes,

  9. Bs Mixing Phase s New Physics W s from ACP(BsJ/) mixing First results from CDF/D0 A.Lenz, U.Nierste

  10. BsJ/ Experimental challenge: Performing an angular analysis to distinguish between CP-odd and CP-even components. Pure CP eigenstates small yield, large bckg. BsJ/ is VV state: L=0, 2  CP-even L=1  CP-odd J/  117k 0.030 Transversity basis: CDF ~4%

  11. s Sensitivity LHCb-Roadmap-2009 • One of first key measurements SM value: s=-0.0368±0.017 Penguin Decays Standard Model: Bs   = s-Decay = 0  zero CP asymmetry 2 fb-1 (10 fb-1) Yield (2 fb-1): 3100 evts, B/S <0.8

  12. Search for New Physics in penguin A.Lenz and very rare decays

  13. Radiative bs penguins Time dependent CP asymmetry to determine photon polarization (SM: mainly LH) _ XsgL(R) B0 B0 XsgR(L) SM: Adir = 0 (direct CPV) Amix= sin2sin0 A = sin2cos 2 fb-1: (A)=0.22 (Adir,mix)=0.11 Fraction of “wrong” polarized photons tan= |A(bsR)|/ |A(bsl)| LHCb-Roadmap-2009

  14. B0  K* Standard Model Model independent approach using Operator Product Expansion Corresponding Wilson coefficients Ci describe short-range physics.

  15. Angular observables in B0  K* Forward-backward asymmetry Observables:l, K, , m2 • Angular observables sensitive to New Physics models • AFB zero-crossing point: dominant theoretical error (FF) cancels Offers a powerful test bench for any New Physics model

  16. B0  K* - LHCb prospects 2 fb-1 2) Fits to decay angle projections: Other angular observables: e.g. K* polarization 1) Simple Counting 10 fb-1 AFB(s) LHCb-20008-041 2 fb-1 3) Full angular fit s [GeV2] Maximum discrimination of NP models

  17. “Very” rare decays: Bs ATLAS < 10-8 (2 fb-1) < 5.8·10-895% CL PRL 100,101802 (2008) 2 fb-1 CMS < 1.4  10-8 (10 fb-1) < 9.3·10-895% CL D0 Note 5344-Conf (2007) 90%CL upper limit BR (x10–9) Expected final CDF+D0 limit Uncertainty from MC stats on bkg SM prediction SM: BR(Bsμ+μ-)= (3.42±0.54)x10-9 BR (x10–9) Large SUSY contributions possible 5 observation SM prediction 3 evidence Discovery  L dt (fb–1)

  18. Conclusion s b • CKM mechanism is dominating effect for CP violation and flavor mixing in the quark sector… but there is room for sizable new effects in B meson decays. • LHCb will try to map-out effects of New Physics • Interesting results can come early (0.5 fb-1) •  from trees w/ precision 8 … 10o • s(BsJ/) w/ precision of 0.06 • Limit for BR(Bs) < 10-8 • LHCb has a lot of opportunities to discover New Physics in a few years of data taking (10 fb-1).

  19. Backup

  20. Outlook – LHCb beyond 10 fb-1 100 fb-1 LHCb upgrade • Run at 10 design luminosity: 21033 • Needs detector and trigger upgrade • Increase trigger efficiency for hadrons by at least a factor 2 • Accumulate data sample of 100 fb-1 100 fb-1 Physics case • CPV in Bs mixing (tree and penguins) • CKM angle  with ~1o precision • Chiral structure of bs decays • Lepton flavor violation in 

More Related