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A. Drutskoy, ITEP, Moscow

A. Drutskoy, ITEP, Moscow. Prospects for  (5S) and B s studies at Super B - factories. 0. Super B Workshop. April 4-7, 2011, Frascati, Italy. SuperB Workshop, Prospects for Y(5S) and B s 0 studies at Super B-factories , April 4-7, 2011, Frascati, Italy A. Drutskoy. e +. B. ¡.

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A. Drutskoy, ITEP, Moscow

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  1. A. Drutskoy, ITEP, Moscow Prospects for (5S) and Bs studies at Super B-factories 0 Super B Workshop April 4-7, 2011, Frascati, Italy. SuperB Workshop,Prospects for Y(5S) and Bs0 studies at Super B-factories, April 4-7, 2011, Frascati, Italy A. Drutskoy

  2. e+ B ¡ (4S) _ B e- e+ e-hadronic cross section 2 CLEO PRL 54, 381 (1985) (4S) (5S) (6S) (6S) 2M(Bs)  Ebeams by 2.7% _ - - - - e+ e- ->(4S) -> BB, whereBisB+orB0meson (cc,ss,uu,dd) _ _ _ _ _ e+ e- -> bb ((5S)) ->B(*)B(*), B(*)B(*)p, BBpp, Bs(*)Bs(*),(1S)pp, X … where B* -> B gandBs* -> Bsg CLEO: 2003: ~0.42 fb-1 Belle: 2005 1.86 fb-1, 2006 21.7 fb-1, 2008 ~27 fb-1, 2009 ~71 fb-1 G ((5S)) = 43  4 MeV/c2 (BaBar) M ((5S)) = 10876  2 MeV/c2

  3. BelleII luminosity upgrade projection 3 Milestone of SuperKEKB 9 month/year 20 days/month Belle II will reach 50 ab-1 in 2020~2021. Integrated Luminosity (ab-1) Commissioning starts mid of 2014 Shutdown for upgrade Peak Luminosity (cm-2s-1) Target: L = 8x1035/cm2/s Year

  4. 4 As is now well known, Japan suffered a terrible earthquake and tsunami on　March 11,　which has caused tremendous damage, especially in the Tohoku area. Fortunately,　all KEK personnel and users are safe and accounted for. The injection linac did suffer significant but manageable damage, and repairs are underway. The damage to the KEKB main rings appears to be less serious, though non-negligible. No serious damage has been reported so far at Belle. Further investigation is necessary. We would like to convey our deep appreciation to everyone for your generous expressions of concern and encouragement.

  5. CLEO PRL 54, 381 (1985) (5S) Hadronic event classification at (5S) 5 ~105 Bs / 1 fb-1 at Y(5S) hadronic events at (5S) u,d,s,c continuum (5S) events bb continuum bb cross-section bb events s(bb) = (0.302 ± 0.014)nb Bs events B0, B+ events (1,2S) X fs = N(Bs(*) Bs(*)) / N(bb) f(Bs*Bs*) fs = (19.5 ± 3.0 )% 2.3 ~90 % Bs* Bs* channel Bs* Bs Bs Bs

  6. f(Bs*Bs*) = (90.1±3.84.0 ± 0.2)% f(Bs*Bs) = (7.3±3.33.0 ± 0.1)% f(BsBs) = (2.6±2.62.5)% Bsand B production rates at ϒ(5S)(at Ecm=10867 MeV ) 0 0/+ 6 _ Bs 0 (19.5 ± 3.0 ) % 2.3 _ _ B ( 73.7± 3.2±5.1) % B0 (77.0±5.8±6.1) % 5.6 B+ (72.1±3.9±5.0) % 3.8 BB: ( 5.5±1.0 ±0.4 ) % _ 0.9 2 - body B*B: ( 13.7 ± 1.3 ±1.1) % _ B*B*: ( 37.5±2.1±3.0 ) % 1.9 _ BB p (0.0 ± 1.2 ± 0.3 ) % _ 3 - body B*B p (7.3 ± 2.3 ± 0.8 ) % 2.1 _ B*B* p (1.0 ± 1.4 ± 0.4 ) % 1.3 Residual (ISR) (9.2 ±3.0 ± 1.0 ) % 2.8

  7. 0 Signature of fully reconstructed Bs and B decays 7 MC simulation:Bs -> Ds-p+andB0 -> D-p+ . _ _ Zoom BBpp _ Bs*Bs* M(Bs*) Bs*Bs* _ Bs*Bs _ _ B(*)B(*)p BsBs _ Bs*Bs _ B*B* _ _ MC B*B BsBs M(Bs) _ E(g) BB Mbc vs DE Mbc vs DE _ _ _ whereBs* -> Bsg e+ e- -> (5S) -> BsBs, Bs*Bs,Bs*Bs*, Bsor B energy (E*B) and momentum (P*B) are reconstructed; no rec.gfrom B(s) * Mbc = E*beam2 – P*B2 , DE = E*B – E*beam Two variables calculated: _ _ _ Signals in BsBs, Bs*Bsand Bs*Bs* channels can be well separated.

  8. Diagrams ofBsdecays studied by Belle with L= 23.6 fb-1 8 Bs→ Ds- p+ Bs→ Ds- Ds+ Bs→ J/y h Bs→ K+K- Bs→f g Bs→g g

  9. Bs decay measurementsperformed on Веlle (L=23.6fb-1) 0 9 > - first measurements, > - unpublished first measurements Reasonable agreement between branching fractions for relatedBs0 и B0 decays

  10. 10 Potential measurements with 1 ab-1 at(5S) Where can SuperB factories be competitive with LHCb by 2016 ? What are advantages of B factories comparing with hadron colliders?

  11. Advantages and disadvantages of B factories. 11 Advantages of Super B factories running at (5S), comparing with hadron-hadron colliders (in particular with LHCb): 1) Low background, clean Bs samples (first LHCb results are rather clean). 2) A few percent systematics in determination of full Bs number in dataset. 3)Measurements of decay modes with many g,p0andhin final state. 4)No problems with trigger forno-vertex andmulti-particle final states. 5)Inclusive measurements (inclusive photon spectrum, semileptonic BF ). 6)Partial reconstruction (“missing-mass” method). 7) Full reconstruction Bs sample can be used to study opposite side Bs. Disadvantages: 1) We have to choose between running at (4S) and(5S). 2) Number of Bs mesons is smaller than in LHCb. 3) In LHCblepton triggerefficiency is also high (close to 100%). 3) Vertex resolution is not good enough to measure Bs mixing (?). If we could measure time-dependent CP, physics program will be much wider.

  12. m+ m+ Beam profile Dz = bgc Dt Bs Bs Y(5S) Feasibility of Bsmixing measurement with two same-sign leptons 12 DzM=pDmsbgc= 22.5mm Toy MC Toy MC 1ab-1 1ab-1 SVR=13mm SVR=10mm SS OS-SS Assuming boost bgc=0.425 Can we reach vertex resolution ~12mm ? Can we increase boost when running at Y(5S) ? Bsmixing can be measured with Single Vertex Resol ~12mm and boost ~0.425

  13. 13 If Bs mixing oscillations cannot be resolved, lifetime difference between CP= + and CP= - Bs decays can be used to search for BSM effects.

  14. Direct DGs measurement using CP-fixed Bsmodes with 1ab-1 14 Toy MC, 4000 events 102.4% 102.4% Vertex resol. is not critical SVR=0mm SVR=40mm No BSM _ _ e+e-->Y(5S) -> Bs*(CP=+)Bs*(CP=-) = Bs(CP=-) g Bs(CP=+) g : CP anti-correlated A exp (G1Dt) , if Dt<0 A1 exp(-G1t1) + A2 exp(-G2 (t1+Dt)) A exp (-G2Dt) , if Dt>0 ~4000 (eff) CP-fixed events with 1000fb-1 => 2.4% accuracy in DGs. CP-fixed:Ds(*)Ds(*)(1000 ev),J/yh(‘)(1500),K+K-(800),D0CPK0(250),J/y f(2200). 4smeasurement of DGs/Gswith 1ab-1 at Y(5S)

  15. DGsCP Bf (Bs->Ds(*) + Ds(*) - ) ~ ~ Gs 1- Bf (Bs->Ds(*) + Ds(*) - ) / 2 DGs/Gsmeasurement fromBf (Bs -> Ds+(*) Ds-(*)) 15 We can test SM comparing directly measured DGs withDGsCP. DGs = DGsCP cos fs fs is small in SM (phase in Vts is small) BSM effects can decreaselifetime differenceDGs. DGsCP= S G(CP=+) – SG(CP= –) Bs->Ds(*) + Ds(*) - decays are CP-even final states with largest BF’s of ~(1-3)% each, saturatingDGsCP. This formula is based on assumptions : 1) Contribution of Bs -> Ds+(*) Ds-(*) np is small 2) Decays Bs -> Ds+ Ds-* and Bs -> Ds+* Ds- * are dominantly CP-even states. Corrections are expected to be small(~5-7%), DGsCPcan be well measured.

  16. Two body Bs decays 16 Many two-body (b->u and penguin) decays can be measured with 1ab-1. Decays with h and h’ mesons are specially interesting. It is possible in some modes to measure time-integrated asymmetry and/or polarization. Best candidates with large branching fractions are: Bs-> K-p+, Bs-> K0 K0 , Bs-> K-r+, Bs-> h(‘) h(‘), Bs-> f f. Phys.Rev. D76, 074018 (2007) Ali et al. Decay mode Bs->Ds-/+K+/- can be used to measure precisely angleg with 1ab-1. Two contributing tree diagrams (Cabibbo-suppressed and b->u) are of the same order: Time-dependent measurement : Z. Phys. C54, 653 (1992) Aleksan, Dunietz, Kayzer Time-integrated (other side CP-tagged Bs ,~5ab-1): Phys.Rev.Lett 85, 252 (2000) Falk, Petrov K+Ds+ Ds-K-

  17. Inclusive Bs decays 17 • Inclusive Bs-> X-l + n decay branching fraction. It was measured • (not published in journals) by Belle with 23.6 fb-1. 2. Inclusive Bs-> Xssg decay branching fraction (Bs-> f g). It requires to develop relevant semi-inclusive method. Partial reconstruction or full reconstruction of other side Bs: • Exclusive Bs-> Ds(*)-l+ n decay branching fractions. • Precise measurements can be done with Belle statistics of ~121fb-1. 2. Exclusive Bs-> DsJ-l+ n decay branching fractions (~1ab-1). 3. Exclusive Bs->K-l+ n decay branching fraction (probably ~1ab-1). 4. Exclusive Bs-> Ds-t+ n decay branching fraction. It requires MC studies (probably ~1ab-1 will be enough).

  18. Leptonic Bs decays 18 1 ab-1 = 108 Bs mesons 1. Measurement of Bs-> m+ m- decay branching fraction. SM: B ~(3.4±0.5)x10-9=>too small PDG: <4.7x10-8 @90%CL 2. Measurement of Bs-> m+ m-g decay branching fraction. SM: B~3x10-9=>too small (not helicity suppressed) BSM up tox5 3. Measurement of Bs-> t+ t- decay branching fraction. SM: B (Bs->t+ t-) ~ 7x10-7, BSM can  up tox10 OK, requires MC study SM: B (Bs-> t+ t-g ) = 1.5x10-8 (hep-ph/0504193), BSM can up tox10 4. Measurement of Bs-> fm+ m- decay parameters. LHCb will do it. Maybe Bs-> h(‘)m+ m- decay is not that easy for LHCb. 5. Measurement of Bs-> fnn decay branching fraction. SM: B ~ 10-5, Full reconstruction Bs, BSM sensitive, OK, requires MC study

  19. Lepton charge asymmetry measurement 19 1 ab-1 = 108 Bs mesons _ _ Asls = (Bf(Bs->l+X) - Bf(Bs->l-X)) / (Bf(Bs->l+X) + Bf(Bs->l-X)) D0: Aslb = (-0.957  0.251  0.146)% ; SM: ~-2x10-4 ; BSM: up to 10-3 Advantage of B factories : separation of Bs and B sources for leptons Technique : selection ofmmandfmmsamples Electrons can be used as well Expected accuracy at Super B factory with 1 ab-1: s(Asls) ~0.3% Asls = ( DGs / DMs ) x tan fs

  20. Measurement of Bs-> gg decay 20 SM: B~ (0.5-1.0) x10-6 Belle (23.6 fb-1) : B(Bs-> gg) < 8.7x10-6 (90% CL) With 1ab-1 (3-5)s measurement of SM branching fraction is expected. With specific set of parameters BSM model branching fraction is increased up to: T.M. Aliev, et al, “Leading logarithmic corrections to the Bs -> g g decays in the two Higgs doublet model”, Nucl. Phys. B515 321 (1998). 2 x 10-6 3 x 10-6 W.J. Huo, et al, “Bs->g g decays with the fourth generation”,hep-ph/0302177 • Gemintern, et al, “Bs->X(s) g g and Bs-> g g in supersymmetry with • broken R-parity”, Phys. Rev. D70 035008 (2004). 5 x 10-6 J.I. Aranda, et al, “Bounding the Bs-> g g decay from Higgs mediated FCNC transitions”, arXiv:1005.5452 (hep-ph). 0.04 x 10-6

  21. Searches for new bottomonium states at(5S) 21 New (almost unexpected) field in (5S) physics: Searches for new bottomonium states In contrast to (4S) data, (5S) can decay in bottomonium states with high rates up to 1% level (next two slides) Why (5S) does not decay only to B and Bs mesons ? Exotic mechanisms ? We don’t know answers to these questions. It is important to develop physics program in this field

  22. larger by > 102 Observation of ϒ(5S) ϒ(nS)p+p- 22 K.-F. Chen et al. (Belle coll), PRL 100, 112001 (2008) Y(5S) -> U(2S) p+p- Y(5S) -> U(1S) p+p-

  23. Production of hb(1P) and hb(2P) at (5S) (R.Mizuk talk, Moriond 2011) 23 Preliminary 121.4 fb-1 MM(+-) spectrum 2S1S 3S1S Smooth background was subtracted Masses consistent with CoG of bJ states, as expected. Anomalous production rates of ~0.5% level.

  24. CLEO PRL 54, 381 (1985) (5S) What else can be done at Super B Factory? 24 PDG (Z->bb, pp at S1/2=1.8TeV) b hadron fraction(%) B+, B0 39.8 ± 1.0 Bs 10.4 ± 1.4 b baryons 9.9 ± 1.7 (90% Lb) Rates at e+e- continuum should be similar, baryon production is large. M(Lb)= (5624 ± 9) MeV/c2 M(Lb)x2 = (11248 ± 18) MeV/c2 => 6.3% up from Y(4S) CME. Can Super B factory CM energy range be increased ? M(Bc)= (6286 ± 5) MeV/c2 _ _ _ _ e+e-(6S,7S) BsBs, LbLb, BcBc, Xb Xb … ?

  25. Conclusions 25 Extensive physics program can be proposed at Super B factories with statistics of 1 ab-1 at Y(5S). Important SM tests can be done. Because we don’t know which BSM model is correct, we should develop comprehensive program with all possible BSM searches. It is important to have good vertex resolution and option with large e+e- CM boost to measure time dependent CP violation.

  26. Belle Detector Cherenkov detector n=1.015~1.030 SC solenoid 1.5T 3.5GeV e+ EM calorimeter (CsI(Tl)) TOF counter 8GeV e- Central drift chamber He(50%)+C2H6(50%) m / KL detector Si vertex detector

  27. / KL detection 14/15 lyr. RPC+Fe →tile scint. CDC: Tracking + dE/dx small cell + He/C2H6 → remove inner lyrs large outer radius faster timing smaller cell 6 Si vtx. det. 4 lyr. DSSD →2 DEPFET pixel lyrs. + 4 lyr. DSSD Belle Upgrade for the Super B Factory TDR: KEK Report 2010-1 CsI(Tl) 16X0 SC solenoid 1.5T pure CsI (endcap)‏ new electronics (waveform sampling) Aerogel Cherenkov counter + TOF counter →“TOP” + Aerogel RICH New readout and computing systems

  28. T.Kawasaki, Atami BNM2008 Jan 2008 Impact Parameter resolution Calculated by TRACKERR r-fdirection z direction [cm] [cm] 0.02 0.03 dz dz resolutoin SuperB SVD3mod SVD3 For p 0.2GeV 0.5GeV 1.0GeV 2.0GeV 0.01 20mm 0 1.4 sinq Occupancy effects. Degradation of intrinsic resolution is included. Efficiency loss is NOT included Beampipe radius is important Competitive performance as the current SVD

  29. Observation of ϒ(5S) ϒ(1S)p+p-, ϒ(2S)p+p- K.-F. Chen et al. (Belle coll), PRL 100, 112001 (2008) U(2S) L= 21.7 fb-1 -> look for: m+m-h+h- U(3S) e+e- -> U(1S) p+p-X U(2S) e+e- -> U(2S) p+p-X U(1S) Signals are about 1%. Is it similar to recently observed Y(4230) -> J/Yp+p- state (hybrid interpret.)? U(1S) CME calibration accur.<1MeV

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