1. Long term B physics strategies in ATLAS Smizanska, Lancaster University

2. ATLAS B-physics important periods
B-physics with 500 mb (top is 8fb) always considered as a candidate for early measurements.
In fact LHC covers very wide range
QCD b-production using inclusive signatures with Br
Tree allowed B-decays Br ~10-3-4
Rare B-decays Br ~ 10-5
Very rare B-decays Br ~
B-physics at LHC is preparing to cover all LHC periods
Early 31-32
Main B-physics x 10 33
Rare di-muon 10 34
Rare di-muon upgraded 10 35

3. Early period ~ 10 31-32 First B-physics measurements
Service for ATLAS: Dominant B-physics signatures will permanently serve for sensitive tests of alignment, calibrations by measuring known B-physics variables: masses, lifetimes.
Jpsi and Upsilon
part of express stream ( B csc-10 note, also Darren Price presentation today).
trigger monitoring (recently started)
for trigger efficiency calibration (B csc note 5)
B-lifetimes after 10 pb-1 serve for alignment tests
First B-physics measurements
Onia production cross sections, polarization ( Vato’s talk today)
B-cross sections, correlations - using semi- inclusive signatures and exclusive B decays in dominant channels.

4. Overview: lifetimes with early data B+→J/y K+ B→J/yK
Overview: lifetimes with early data B+→J/y K+ B→J/yK* Bs → J/yf and Lb → J/yL
Statistics with
10 pb-1
Life time Statistical error
World today (stat + syst) B+
B+→J/y K+
1600
2.2 %
0.67 % B0
B0→ J/y K0*
900
3.1 %
0.9 %
Statistics with 200 pb-1
32000
0.49 %
18000
0.69 %
Bs (single t fit)
Bs→ J/y f
1800
4.2 %
2.7 % Lb
Lb→ J/yL
520
5.8 % 5%
With 10 pb-1 we start to be useful for alignment tests
With 200 pb-1 we improve words precisions

5. Main B-physics program @ x . 10 33
Accommodate unprecedently large statistics of B-decays to
increase today’s best precisions and discover new channels.
ATLAS supports very wide program for B-decays and
B-production studies:
High precision measurements of CPV to reach sensitivity of BSM signatures (Roger’s talk today).
Semi-muon rare decays with BSM effects: ATLAS supports 6 exclusive channels for B+ Bs Bd Lb. Most critical – LVL2 trigger work done in two B csc NOTEs.
New or better measurements for B-baryons and double HF hadrons (bc). Both production and decay.
Very rare B decays program – vis further slide.

6. 1033 and overview of Bs  mm
Today experimental limit still factor of 20 above SM – leave space for BSM
Tevatron can improve by factor 5
ATLAS
SM sensitivity after
Measure SM Br after
LHCb always run fb-1 year
SM sensitivity after 1Y
Measure SM Br after 3Y
1Y Y Y Y
Also will analyze the differential distributions like the invariang mass of the dimuon in radiative decays
ATLAS

7. Motivation for rare B muon decays @10 35 with upgraded detector
will test SM for Bs  mm so what motivations for 1035 ?
BSM can not only increase but possibly decrease Br vrt SM (destructive interference).
Additional statistics - measure Bd  mm
Dedicated backgrounds may not be well measured with so 1035 chance to continue
t  mmm (< )3-lepton signature decrease backgr. rate

8. First estimates of Bs  mm @ upgraded detector
s Rxy(m)
s M (MeV)
CSC full MC
||<2.5
26.0 89
Upgrade:
B-layer 3.7 cm X0=2.6%
results from ID model *
||=0
||=1.5
20.5
24.0 63 92
* Extracted from Upgrade workshop, Dec.2007.
 ID performance can be even better in upgraded tracker mainly due to radius 3.7 cm
Cross sections
ratio
and *10 for luminosity
Bs  m6m6 / Bs  m15m15
~ 40
~ 4
Bs  m6m6 / Bs  m6m6  m6
~ 35
~ 3.5
 To reduce L1 output rate both ‘methods’ will reduce signal times vrt 1034 however worth to start detailed studies.
 t  mmm ideal signature

9. Summary B-physics in ATLAS is a complex program
Highest signatures will serve as permanent tools to control alignments, determine calibrations, magnetic field and material effects.
B-physics and B-trigger already in CSC. More contacts with data control, alignment group, trigger calibration, monitoring groups starting now.
At 1033 – grand statistics with LHC golden channels – CPV beyond SM, doubly HF hadrons, semi-leptonic rare decays, new limits on B-mm
1034 test SM for Bs  mm
1035 test SM for Bd  mm, improve Bs  mm, test t  mmm

10. Summary, cont
B-physics group is actively participating in software developments, Event data model, data production tools, validations and tests activities. (only UK physicists mentioned here)
Physics validation group – S. Dallison, M.Smizanska
Final Dress Rehearsal – J.Catmore
Even Data Model, Data production tools and R.Jones, J.Catmore.
Physics Analysis, event tag, vertexing code and beam spot: J.Catmore, G.Borrisov, J.Walder, M.Smizanska.
Generator code development and MC validations: D.Price, M.Smizanska, V.Kartvelishvili
Reconstruction code - signatures needed for B-physics: V0, electrons V.Kartvelishvili, E. Bouhova, R.Henderson.
B-physics and B-trigger group work in close collaborations already for 10 years! Currently both conveners from UK.