Rare B and  decays and searches for New Physics Roger Barlow Manchester University and New (preliminary) results, mostly but not entirely from the B factory experiments Belle and BaBar.

Roger Barlow: Rare B and tau Decays and New Physics Slide 2 Why look for Rare Decays? Our chance to see them is when the Standard Model amplitudes are small: Rare decays u bb H+H+ ++ If new particles are to appear on-shell at high energy colliders, they must appear in virtual loops and affect amplitudes

Roger Barlow: Rare B and tau Decays and New Physics Slide 3 What made it possible? Measuring Branching ratios of ~10 -6 needs millions of events Physics progress possible thanks to machine physicists at SLAC and KEK designed and built B factories operating in a new high-current regime, continually faced and overcame new problems and challenges. design luminosities met and exceeded.

Roger Barlow: Rare B and tau Decays and New Physics Slide 4 Huge backgrounds from other Bs and e + e -  q  q Use of  E=E B -  E i and M ES =  E B 2 -(  p i ) 2 “Blind Analysis” Tune cuts without looking in the M ES -  E ‘signal box’ Use data sidebands (rather than Monte Carlo) to estimate background “Finding a needle in haystack.” M ES (GeV/c 2 )  E(GeV) (taken from Sekula’s talk. One of many)

Roger Barlow: Rare B and tau Decays and New Physics Slide 5 Continuum suppression from combined information from shape variables “Single-B beam” technique: Reconstruct one “tag” B in a common decay mode (hadronic or semileptonic). Remaining particles must also form a B Limits from N=  S + b N small Uncertainties on , b Other Experimental techniques

Roger Barlow: Rare B and tau Decays and New Physics Slide 6 Contents B decays –Leptonic –Radiative b  s  and b  s l + l - b  d  and b  d l + l - –Hadronic Charmless Branching Fractions Charge Asymmetries Polarisation Tau decays

Roger Barlow: Rare B and tau Decays and New Physics Slide 7 B Decays to leptons Proceeds through one or two weak bosons with strong CKM suppression – door open for NP particles to contribute Free of hadronic uncertainties in final state u bb H+H+ ++ ++ -- bb d,s u bb W+W+ ++ ~ bb d,s W W u,c,t -- ++ Plus many other diagrams

Roger Barlow: Rare B and tau Decays and New Physics Slide 8 B      CP, Rare decays, CKM V Browder (Belle) Sekula (BaBar) Important as W (suppressed by V ub ) can be replaced by charged Higgs, etc Difficult due to neutrinos in the final state SM prediction (1.59  0.40) x (depends on f B and V ub ) tag with fully reconstructed B mesons (180 channels) Tag with B  D(*)l

Roger Barlow: Rare B and tau Decays and New Physics Slide 9 B      Identify possible  in common decay mode Look at extra calorimeter energy (validate with for D*l ) H+?H+? CP, Rare decays, CKM V Browder (Belle) Sekula (BaBar) Extra E(GeV)

Roger Barlow: Rare B and tau Decays and New Physics Slide 10 Results Belle and BaBar results are similar. Agree within errors Can be combined (R. Faccini) to give (1.36  0.48)x10 -4 (new) BF(B +  +  )= (0.88  0.11) x10 -4 BR< %CL (revised). 3.5  significance BF(B +  +  )

Roger Barlow: Rare B and tau Decays and New Physics Slide 11 Impact Limits on e.g. 2 Higgs doublet model: W.S.Hou, PRD 48, 2342 (1993) SM prediction enhanced/reduced by factor r H CP, Rare decays, CKM V Browder (Belle) Or: Within the SM, use the value of BF(B +  +  ) to give a measurement of f B

Roger Barlow: Rare B and tau Decays and New Physics Slide 12 B    and e  Helicity Suppressed Use hadronic tags: B fully reconstructed as B to D(*) X Lepton is monoenergetic in signal-B rest frame Limits 90% CL) <7.9 x10 -6 for e (SM ~ ) <6.2 x10 -6 for  (SM ~ ) CP, Rare decays, CKM V Sekula (BaBar) Lepton momentum in B frame (GeV/)

Roger Barlow: Rare B and tau Decays and New Physics Slide 13 B 0 to l l  FCNC and helicity suppressed, but an initial state photon allows helicity flip SM predictions of order (10 -15, respectively without the  ) See 0 events for e, 3 events for  (but compatible with background) Limits (at 90% CL) BR(B  ee  )< 0.7 x BR(B  )< 3.4 x (simulated) CP, Rare decays, CKM V Sekula (BaBar)

Roger Barlow: Rare B and tau Decays and New Physics Slide 14 B  K*  Tag on other B Identify K* Look for extra energy SM prediction ~1.3 x Signal is B  K* + missing mass. (Could be light dark matter particle: publications by M. Pospelov et al.) CP, Rare decays, CKM V Browder (Belle) (at 90% C.L) Extra Calorimeter Energy (GeV)

Roger Barlow: Rare B and tau Decays and New Physics Slide 15 B 0   +  - Expected BG Events seen 12 BF (95% CL) <1.0x10 -7 <3.0x10 -8 B 0 s   +  - B 0 d   +  - CP, Rare decays, CKM IV-V Farrington (CDF) Strauss (DØ) Sivoklokov (ATLAS) Langenegger (CMS) Ruf (LHCb) DØ analysis not yet complete. Combines B s and B d. Expect limit ~ Have result on BR( B  ) BR < 4.1 x10 95% LHC experiments will do this very precisely SM predicts B s :(3.4  0.5)x10 -9 B d :(1.0  0.1)x NP can boost this by ~100

Roger Barlow: Rare B and tau Decays and New Physics Slide 16 Radiative B decays FCNC process suppressed in SM: sensitive to new particles in loops b  s  Inclusive and many exclusive measurements b  sl + l -: More information from kinematics b  d  : strongly suppressed but open to different physics b  d l + l - : on the way

Roger Barlow: Rare B and tau Decays and New Physics Slide 17 B  s  inclusive ‘Fully Inclusive’ and ‘sum of exclusives’ (38 modes) Heavy Quark Physics I &III Hurth (Theory) Convery (BaBar) NLO calculation (3.61 ) x10 -4 result: (E  >1.9GeV) = (3.67  0.29  0.34  0.29) x10 -4 HFAG average (3.55  0.24  0.03) x Branching Fraction now well measured. Theory and experimental error similar Not much room for New Physics here Constrains model builders

Roger Barlow: Rare B and tau Decays and New Physics Slide 18 B  s  exclusive Lots of channels – Branching Fractions measured – CP violating asymmetries measured If nonzero these would be a signature of New Physics Heavy Quark Physics III Limosami (Belle) Example: B  K 0 s  0   t(ps)

Roger Barlow: Rare B and tau Decays and New Physics Slide 19 B  Kl l B  K*l l Standard Model Amplitudes have 3 parts with different kinematics. Check out each separately through Wilson Coefficients: Photon C7 Vector EW C9 Axial EW C10 Dilepton mass q 2 CKM factors x  C i (q 2 ) x local operators CP, Rare decays, CKM VI Kovalskyi (BaBar) BSM VI Hamel de Monchenault B  Kll (46 events)  E(GeV) M ES (GeV/c 2 )

Roger Barlow: Rare B and tau Decays and New Physics Slide 20 CP, Rare decays, CKM VI Kovalskyi (BaBar) K*ll Asymmetry as a function of q 2 Angular variables e.g.  *: angle of l l pair in their rest frame. C10 interferes with C7/C9 to give asymmetry

Roger Barlow: Rare B and tau Decays and New Physics Slide 21 B  d  First observation of B +   +  CP, Rare decays, CKM VI Kovalskyi (BaBar) B +  +  B 0  0  M ES (GeV/c 2 )

Roger Barlow: Rare B and tau Decays and New Physics Slide 22 CP, Rare decays, CKM VI Kovalskyi (BaBar) bb d,s W W t b t  d,  s t ds |Vtd/Vts|= Compare with B  K*  Same CKM elements as mixing – but a non-trivial test

Roger Barlow: Rare B and tau Decays and New Physics Slide 23 B   l + l - Prediction: few Measure B +   + l + l - and B 0   0 l + l - with l =e or  (and e -  ) Total limit 7.9 x at 90% CL for B + ( twice B 0 ) Amazing to be probing at this level CP, Rare decays, CKM VI Kovalskyi (BaBar) M ES (GeV/c 2 )  E(GeV)

Roger Barlow: Rare B and tau Decays and New Physics Slide 24 Charmless Hadronic Decays Many modes Will present collected branching ratios Will present measurements of time-integrated CP violation A CP : they follow on directly from differences in charge conjugate decay states –from the B + /B - difference - trivial –From self-tagged neutral modes – trivial –From C part of CP+mixing fit – nontrivial but standard

Roger Barlow: Rare B and tau Decays and New Physics Slide 25 Examples Heavy Quark Physics I Dragic (Belle) Bona (BaBar) M ES (GeV/c 2 )  E(GeV)

Roger Barlow: Rare B and tau Decays and New Physics Slide 26 2 body  -K combinations Results on many other decays. See talks by Dragic, Bona, Latham and Schümann in Heavy Quark Physics Session I Heavy Quark Physics I Dragic (Belle) Bona (BaBar)

Roger Barlow: Rare B and tau Decays and New Physics Slide 27

Roger Barlow: Rare B and tau Decays and New Physics Slide 28 B  K +  - /K -  + Direct CP violation Experiments agree: BaBar: A CP =   Bel A CP =   CP, Rare decays, CKM IV Di Marco (BaBar) Unno (Belle)

Roger Barlow: Rare B and tau Decays and New Physics Slide 29 Direct CP in K  Competing amplitudes with different strong and weak phases A CP should be the same for K +  - and K +  0 (Gronau: hep-ph ) Current averages (HFAG) A CP (K +  - )=  A CP (K +  0 )=  Difference 0.14  0.03 – a long way from zero Maybe colour-suppressed trees are responsible Maybe New Physics

Roger Barlow: Rare B and tau Decays and New Physics Slide 30 Lipkin Sum Rule R Lipkin =2  (B +  K +  0 )+  (B 0  K 0  0 )  (B +  K 0  + )+  (B 0  K +  - ) From isospin and assuming the b  s penguin diagram dominates R should be 1+ O (10 -2 ) Obtain (HFAG average) R Lipkin =1.06  0.05 (Was 1.25  0.10 in 2003)

Roger Barlow: Rare B and tau Decays and New Physics Slide 31 B  K  ratios Can form many ratios, especially (A Buras, R Fleischer et al, Phys J C 45 ( ) 2006) R n =  (K +  - ) R c =2  (K +  0 ) 2  (K 0  0 )  (K 0  + ) Heavy Quark Physics I Dragic (Belle) Obtain (HFAG averages) R n =0.99  0.07 R c =1.11  0.07 Agree with each other And with SM predictions The “K  puzzle” is no more

Roger Barlow: Rare B and tau Decays and New Physics Slide 32 The Polarisation Puzzle B  V V decays are spin 0 to spin1+spin1 Should be 100% longitudinally polarised (if tree or penguin dominates) Measurements confute this – for heavier V especially Needs to be understood – affects CP decomposition More data now available

Roger Barlow: Rare B and tau Decays and New Physics Slide 33 B  0  0 See 98  22 events - 3  significance BR (1.16  0.27)10 -6 Fit longitudinal polarisation f l = 0.86  0.05 Measurement needed for B 0  +  -, used for alpha Informs penguin uncertainty in  determination CP, rare decays, CKM III Telnov (BaBar) M ES (GeV/c 2 )  E(GeV)

Roger Barlow: Rare B and tau Decays and New Physics Slide 34 B   K* and f(980)K* f L around 0.5, as in B   K* as opposed to ~1 from simple models Heavy Quarks I Bona (BaBar)

Roger Barlow: Rare B and tau Decays and New Physics Slide 35 More on B to V V CDF measure longitudinal polarisation in  K*,  K* Confirm BaBar and Belle results that polarisation is not 100%   on the way CP, rare decays, CKM VI Bussey (CDF) M(  K  ) (GeV)

Roger Barlow: Rare B and tau Decays and New Physics Slide 36 Rare Tau Decays Search for New Physics in decays with Lepton Flavour Violation The B factories are also  factories  (  +  - ) = 0.89 nb at  s = M(  ) Total sample of ~1.5 billion tau leptons BSM VI Hayasaka

Roger Barlow: Rare B and tau Decays and New Physics Slide 37 Compendium of results Mode x10 -7 Modex10 -7    Belle0.45   lll 1.1  3.5 ee BaBar1.1     + e  e  BaBar1.1    Belle0.65      e  e + Belle1.9 ee Belle0.92   lhh BaBar 0.7  4.8    ' Belle1.3 ++ BaBar0.7 e'e' Belle1.6 lV0lV0 Belle 2.0  7.7     Belle1.2    0 Belle2.0 ee Belle0.80      BaBar0.59    Ks Belle0.52      BaBar0.58   e Ks Belle0.60      BaBar0.72      BaBar1.5 BSM VI Hayasaka

Roger Barlow: Rare B and tau Decays and New Physics Slide 38 General techniques Divide event into two hemispheres ‘Tag side’ usual 1prong (e, , ,  ) or 3 prong  decay. Different analyses use different tags, trading purity for numbers. ‘Signal side’ with no neutrinos. Powerful energy/momentum constraint. e e     generic  decay signal event

Roger Barlow: Rare B and tau Decays and New Physics Slide 39    l      l  K 0 l  is   or e . Theoretical predictions vary from ~ for SM (with mixing) upwards New 90% CL limits Br (  -  e -  ) < 12 x Br (  -   -  ) < 4.1 x Br (  -  e - K S ) < 5.6 ×10 -8 Br (  -   - K S ) < 4.9 ×10 -8 (hep-ex/ ) BSM VI Hayasaka Tan 

Roger Barlow: Rare B and tau Decays and New Physics Slide 40  -  -,  K -,  -,  K – Look for B-L conserved processes as allowed in the Standard Model Look for B-L violating processes as Baryogenesis may need them CL  -  - C 0.42  <  -   - V 0.56  <  -  K - C 0.26  <  -   K - V 0.12  < Decays to non-strange baryons ruled out through proton lifetime measurements BSM VI Hayasaka  E(GeV)

Roger Barlow: Rare B and tau Decays and New Physics Slide 41   in  and 3  modes Limit 1.6 x10 90% CL (BaBar) 0.65 x10 90% from Belle MSSM prediction BSM VI Hayasaka Tan  M A (GeV/c 2 )

Roger Barlow: Rare B and tau Decays and New Physics Slide 42 Y(1S)  CLEO result on Lepton flavour violation Detect  through decay to e BR< LFV Scale  >1 TeV   (  e ) BSM VI Besson(CLEO) p  /Ebeam p e /Ebeam

Roger Barlow: Rare B and tau Decays and New Physics Slide 43 Putting it all together An example: MSSM parameter space Isidori and Paradisi hep-ex One set of Parameters { ,A U, sparticle masses} Restrictions on M H, Tan  Due to b  s  B s  g-2  M B B  BSM VI Hamel de Monchenault M(H + ) Tan 

Roger Barlow: Rare B and tau Decays and New Physics Slide 44 Conclusion BaBar and Belle are probing physics at the TeV scale, exploring parameter spaces of proposed New Physics models Limits on Higgs Masses, Tan , SUSY particles. Precision Frontier and Energy Frontier are Complementary. LHC results will benefit from Rare Decay information. Standard Model beginning to be heavily stressed A SuperB factory would stress it even further