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1 S. Stone Syracuse Univ. May 2003 Heavy Quark Physics Far too much interesting Material to include in 40 min. Apologies in advance.
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2 Physics Goals Discover, or help interpret, New Physics found elsewhere using b & c decays - There is New Physics out there: Standard Model is violated by the Baryon Asymmetry of Universe & by Dark Matter Measure Standard Model parameters, the “fundamental constants” revealed to us by studying Weak interactions Understand QCD; necessary to interpret CKM measurements
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3 The Basics: Quark Mixing & the CKM Matrix A,, and are in the Standard Model fundamental constants of nature like G, or EM multiplies i and is responsible for CP violation We know =0.22 (V us ), A~0.8; constraints on & d s b u c t mass massmass
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4 The 6 CKM Triangles From Unitarity “ds” - indicates rows or columns used There are 4 independent phases: ( can be substituted for or )
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5 All of The CKM Phases The CKM matrix can be expressed in terms of 4 phases, rather than, for example, A, , not independent & probably large, small ~1 o, smaller
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6 Required Measurements |V ub /V cb | 2 = ( 2 + 2 )/ 2 use semileptonic B decays m d and m s are measured directly in B d and B s mixing. There is a limit on the ratio which is a function of V td /V ts and depends on (1- ) 2 + 2 K is a measure of CP violation in K L decays, a function of , and A Asymmetries in decay rates into CP eigenstates f (or other states) measure the angles & , sometimes with little or no theoretical model errors BoBo BoBo
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7 | V ub | a case study Use semileptonic decays c >> u, so difficult exp Also difficult theoretically Three approaches Endpoint leptons: Clear signal seen first this way; new theory enables predictions Make mass cuts on the hadronic system; plot the lepton spectrum. Problems are the systematic errors on the experiment and the theory. Exclusive B or decays. Data are still poor as is theory. Eventually Lattice Gauge calculations should be able to remove this problem
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8 V ub from lepton endpoint V ub both overall rate & fraction of leptons in signal region depends on model. Use CLEO b s spectrum to predict shape CLEO: V ub =(4.08±0.34 ±0.44±0.16 ±0.24)x10 -3 BABAR: V ub =(4.43±0.29 ±0.25±0.50 ±0.35)x10 -3 theory errs : V ub formula, using s Luke: additional error >0.6x10 -3 due to: CLEO Y(4S) data b c continuum Shape from b s b u subleading twist, annihilation CLEO
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9 V ub Using Inclusive Leptons ALEPH & DELPHI, OPAL select samples of charm-poor semileptonic decays with a large number of selection criteria Mass < M D b u Can they understand b c feedthrough < 1% ? |V ub |=(4.09 0.37 0.44 0.34)x10 -3 DELPHI
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10 Problem According to Luke PROBLEM: QCD m B and m D 2 aren’t so different! ïkinematic cut and singularity are perilously close … SOLUTION: Also require q 2 >~7 GeV 2
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11 V ub using reconstructed tags - BABAR Use fully reconstructed B tags |V ub |=(4.52 0.31 (stat) 0.27 (sys) 0.40 (thy) 0.09 (pert) 0.27 (1/m b 3 ) ) x10 -3 Preliminary
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12 V ub from Belle Two techniques (Both Preliminary) |V ub | = 5.00 0.60 0.23 0.05 0.39 0.36 10 -3 stat.syst. |V ub | = 3.96 0.17 0.44 0.34 0.26 0.29 10 -3 bcbcbubu stat.syst. bcbcbubu “D ( * ) ln tag” “ reconstruction and Annealing uses Mx 7” theor.
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13 V ub from exclusives: B B Use detector hermeticity to reconstruct CLEO finds rough q 2 distribution BABAR finds (GeV) CLEO
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14 |V ub | Summary All measurements nicely clustered. RMS ~0.3x10 -3 However, there are theoretical errors that might all have not been included (see Luke) Also previous values may have influenced new values Safe to say |V ub |=(4.0±1.0)x10 -3 Future: More and better tagged data from B-factories Lattice calculations (unquenched) for exclusives in high q 2 region
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15 B d Mixing in the Standard Model Relation between B mixing & CKM elements: F is a known function, QCD ~0.8 B B and f B are currently determined only theoretically in principle, f B can be measured, but its very difficult, need to measure B o Current best hope is Lattice QCD
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16 B s Mixing in the Standard Model When B s mixing is measured then we will learn the ratio of V td /V ts which gives the same essential information as B d mixing alone: |V td | 2 =A 2 4 [(1- ) 2 + 2 ] 1/f B B B 2 |V td | 2 / |V ts | 2 =[(1- ) 2 + 2 ] f Bs B Bs 2 /f B B B 2 Circle in ( ) plane centered at (1,0) Lattice best value for Partially unquenched
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17 Upper limits on m s P(B S B S )=0.5 X S e - S t [1+cos( m S t)] To add exp. it is useful to analyze the data as a function of a test frequency g(t)=0.5 S e - S t [1+ cos( t)] 4 discovery limit LEP + SLD
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18 Status of sin(2 ) B 0 f CP sin2b = 0.741 0.067 0.034 BABAR sin2b =0.719 0.074 0.035 Belle sin2b = 0.73 0.06 Average sin2b = 0.741 0.067 0.034 BABAR sin2b =0.719 0.074 0.035 Belle sin2b = 0.73 0.06 Average 78 fb -1 f CP =J/ K s, K s, etc.. No theoretical uncertainties at this level of error
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19 Current Status Constraints on & from Nir using Hocker et al. Theory parameters exist except in Asymmetry measurements, because we measure hadrons but are trying to extract quark couplings. They are allowed to have equal probability within a restricted but arbitrary range Therefore large model dependence for V ub /V cb, K and m d, smaller but significant for m s and virtually none for sin(2 ). The level of theoretical uncertainties is arguable sin(2 ) sin(2 ) may be consistent with other measurements
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20 for s get K - Bo+-Bo+- In principle, the CP asymmetry in B o measures the phase . However there is a large Penguin term (a “pollution”) (CLEO+ BABAR+BELLE): B (B o + - ) = (4.8 ±0.5)x10 -6 B (B o K ± ) =(18.6±1.0)x10 -6 A CP ( t)=S sin( m d t)-C cos( m d t), where S C To measure , use B o see Snyder & Quinn PRD 48, 2139 (1993) )
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21 Results Inconsistent Results! S C S 2 +C 2 Belle -1.23±0.42 0.77±0.28 2.1±2.2 BABAR 0.02±0.34 -0.30±0.34 0.1±0.3 -5 0 5 t (ps) BABAR Each exp ~80 fb -1
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22 Progress on Best way to measure is 2 nd best is Another suggestion is D o K* ± K (Grossman, Ligeti & Soffer hep-ph/0210433)
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23 Currently available data Belle signals (also B + ) Where is a strong phase & These data do not constrain BABAR has similar results signal
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24 New Physics Tests We can use CP violating or CP related variables to perform tests for New Physics, or to figure out what is the source of the new physics. There are also important methods using Rare Decays, described later These tests can be either generic, where we test for inconsistencies in SM predictions independent of specific non-standard model, or model specific
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25 Generic test: Separate Checks Use different sets of measurement s to define apex of triangle (from Peskin) Also have K (CP in K L system) Magnitudes B d mixing phase B s mixing phase Can also measure via B - D o K -
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26 Generic Test: Critical Check using Silva & Wolfenstein (hep-ph/9610208), (Aleksan, Kayser & London), propose a test of the SM, that can reveal new physics; it relies on measuring the angle . Can use CP eigenstates to measure B s J/ Can also use J/ but a complicated angular analysis is required The critical check is: Very sensitive since 0.2205±0.0018 Since ~ 1 o, need lots of data
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27 Rare b Decays New fermion like objects in addition to t, c or u, or new Gauge-like objects Inclusive Rare Decays such as inclusive b s , b d , b s + Exclusive Rare Decays such as B B K* + : Dalitz plot & polarization + - A good place to find new physics Ali et. al, hep-ph/9910221 SUSY examples
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28 Inclusive b s CLEO B (b s )= (2.85 ± 0.35 ± 0.23)x10 -4 +ALEPH, Belle & Babar Average (3.28 ± 0.38)x10 -4 Theory (3.57 ± 0.30)x10 -4 CLEO
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29 Implications of B (b s ) measurement Measurement is consistent with SM Limits on many non-Standard Models: minimal supergravity, supersymmetry, etc… Define ala’ Ali et al. R i =(c i SM +c i NP )/c i SM ; i=7, 8 Black points indicate various New Physics models (MSSM with MFV) SM
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30 B K (*) + - Belle Discovery of K + - They see K + - BABAR confirms in Ke + e - Only u.l. on K* + -
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31 B X s + - Belle finds B (b s + - ) = (6.1 ± 1.4 )x10 -6 Must avoid J/ , ´ Important for NP +1.4 -1.1 H eff = f(O 7, O 9, O 10 )
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32 Tests in Specific Models: First Supersymmetry Supersymmetry: In general 80 constants & 43 phases MSSM: 2 phases (Nir, hep-ph/9911321) NP in B o mixing: D, B o decay: A, D o mixing: K ProcessQuantity SMNew Physics B o J/ K s CP asym sin(2 )sin2( D ) BoKsBoKs CP asym sin(2 )sin2( D A ) DoK-+DoK-+ CP asym 0 ~sin( K ) NP Difference NP
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33 CP Asymmetry in B o K s Non-SM contributions would interfere with suppressed SM loop diagram New Physics could show if there is a difference between sin(2 ) measured here and in J/ Ks Measurements: BABAR: -0.18±0.51±0.07 Belle: -0.73±0.64±0.22 Average: -0.38±0.41 2.7 away from 0.73 - bears watching, as well other modes
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34 relies on finite strong phase shift MSSM Predictions from Hinchcliff & Kersting (hep-ph/0003090) Contributions to B s mixing CP asymmetry 0.1sin cos sin( m s t), ~10 x SM B s J B-K-B-K- Contributions to direct the CP violating decay Asym=(M W /m squark ) 2 sin( ), ~0 in SM BABAR u.l Asy=(3.9±8.6±1.1)%
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35 Extra Dimensions – only one Extra spatial dimension is compactified at scale 1/R = 250 GeV on up Contributions from Kaluza-Klein modes- Buras, Sprnger & Weiler (hep-ph/0212143) using model of Appelquist, Cheng and Dobrescu (ACD) No effect on |V ub /V cb |, M d / M s, sin(2 )
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36 One Extra Dimension Precision measurements needed for large 1/R –8% –10 0 +72%
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37 SO(10) ala’ Chang, Masiero & Murayama hep-ph/0205111 Large mixing between and (from atmospheric oscillations) can lead to large mixing between b R and s R. This does not violate any known measurements Leads to large CPV in B s mixing, deviations from sin(2 ) in B o K s and changes in the phase ~ ~
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38 Possible Size of New Physics Effects From Hiller hep-ph/0207121
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39 Revelations about QCD BABAR discovery of new narrow D s + o state and CLEO discovery of narrow D s * + o state Double Charm Baryons The C (2S) and implications for Potential Models (no time) The Upsilon D States (no time)
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40 The D s o state “ Narrow” state, mass 2316.8±0.4±3.0 MeV width consistent with mass resolution ~9 MeV found by BABAR Lighter than most potential models What can this be? DK molecule Barnes, Close & Lipkin hep-ph/0305025 “Ordinary” excited cs states: D**, narrow because isospin is violated in the decay. Use HQET + chiral symmetry to explain. Bardeen, Eichten & Hill hep-ph/0305049 Etc… D s * New BABAR +
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41 D s ** States D s ** predicted J p : 0 +, 1 +, 1 + & 2 +. One 1 + & 2 + seen. Others predicted to be above DK threshold and have large ~200 MeV widths, but this state is way below DK threshold The D s o decay from an initial cs state violates isospin, this suppresses the decay width & makes it narrow. So the low mass ensures the narrow width Decays into D s , D s * and D s + - are not seen. If the 2317 were 1 + then it could decay strongly into D s + - but it cannot if it’s 0 + + + + ++ +
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42 CLEO Sees Two Mass Peaks These two states can reflect into one another D s o D s * o not to bad, ~9%, because you need to pick up a random D s * signal region D s * sideband region Ds*oDs*o DsoDso m=349.3±1.1 MeV =8.1±1.3 MeV m= 349.8±1.3 MeV = 6.1±1.0 MeV
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43 Feed Down: D s (2460) Signal, Reconstructed as D s (2317) All events in the D s * 0 mass spectrum are used to show the D s (2460) signal “feed down” to the D s (2317) spectrum. Feed down rate is 84%
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44 Unfolding the rates We are dealing with two narrow resonances which can reflect (or feed) into one another From the data and the MC rates can be unfolded
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45 Upper Limits on other D s (2317) modes Mode Yield Efficiency(%) 90% cl Theory Corrected for feed across Theory: Bardeen, Eichten and Hill DsoDso 150±4913.1±0.7 - 1 DsDs -22±1318.4±0.9<0.057 0 Ds*Ds* -2.0±4.1 5.3±0.4<0.078 0.08 Ds+-Ds+- 1.6±2.619.6±0.7<0.020 0
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46 Belle Confirms Both States M(D s + π 0 ) M(D s *+ π 0 ) M=(2317.2±0.5) MeV =(8.1 ±0.5) MeV M=(2459±1.9) MeV =(7.0 ±1.7) MeV Also see “feed up”
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47 Conclusions on D s **’s CLEO confirms the BABAR discovered narrow cs state near 2317 MeV, measures mD s (2320)-mD s =350.4±1.2±1.0 MeV CLEO has observed a new narrow state near 2463 mD s (2463)-mD s *=351.6±1.7±1.0 MeV Belle confirms both states The mass splittings are consistent with being equal (1.2±2.1 MeV) as predicted by BEH if these are the 0 + & 1 + states The BEH model couples HQET with Chiral Symmetry and makes predictions about masses, widths and decay modes. These results provide powerful evidence for this model Seen modes and u.l. are consistent with these assignment; except 1 + D s + - is above threshold for decay, predicted to be 19% but is limited to <8.1% @ 90% c. l.
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48 Selex: Two Isodoublets of Doubly Charmed Baryons cc ++ (J=1/2 + )? cc ++ (J=1/2 - )? cc + (J=1/2 + )? cc + (J=1/2 - )? Consider as (cc)q - BEH
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49 The Future Now & near term Continuation of excellent new results from Belle & BABAR B s physics, especially mixing from CDF & D0 CLEO-c will start taking data in October on LHC era Some b physics from ATLAS & CMS Dedicated hadronic b experiments: LHCb & BTeV (at the Tevatron) – enhanced sensitivity to new physics
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50 Summary of Required Model Independent Measurements for CKM tests
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51 CDF measures B s D s - needed for B s mixing For f s /f d = 0.27±0.03, B(B s )/B(B d )=1.6±0.3 + o
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52 BTeV & LHCb Dedicated Hadron Collider B experiments Tevatron LHC LHCb Could find narrow B s ** states P b WO 4
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53 BTeV & LHCb Physics highlights Sensitivity to B s mixing up to x s ~80 Large rare decay rates B o K* o + - ~2500 events in 10 7 s Measurement of to ~7 o using B s D s K - Measurement of to ~4 o using B o (BTeV) Measurement of to ~1 o using B o J/ (BTeV)
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54 Conclusions There have been lots of surprises in Heavy Quark Physics, including: Long b Lifetime B o – B o mixing Narrow D s ** states We now expect to find the effects of New Physics in b & c decays!
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