1 / 53

Flavor , Charm , CP Related Physics

Flavor , Charm , CP Related Physics. Hai-Yang Cheng Academia Sinica, Taipei. PASCOS, Taipei November 22, 2013. Outline: Quark and lepton mixing matrices Baryonic B decays Direct CP violation in D decays

tuyet
Télécharger la présentation

Flavor , Charm , CP Related Physics

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. Flavor, Charm, CP Related Physics Hai-Yang Cheng Academia Sinica, Taipei PASCOS, Taipei November 22, 2013

  2. Outline: • Quark and lepton mixing matrices • Baryonic B decays • Direct CP violation in D decays • Direct CP violation in B decays See the talk of Rodrigues (11/21)

  3. Quark & lepton mixing matrices

  4. CP Violation in Standard Model VCKM is the only source of CPV in flavor-changing process in the SM. Only charged current interactions can change flavor Kobayashi & Maskawa (’72) pointed out that one needs at least six quarks in order to accommodate CPV in SM with one Higgs doublet 1>>1>>2 >>3 Physics is independent of a particular parameterization of CKM matrix, but VKM has some disadvantages : • Determination of 2 & 3 is not very accurate • Some elements have comparable real & imaginary parts 4

  5. Maiani (’77) advocated by PDG (’86) as a standard parametrization. However, the coefficient of the imaginary part of Vcb and Vts is O(10-2) rather than O(10-3) as s23  10-2 In 1984 Ling-Lie Chau and Wai-Yee Keung proposed a new parametrization 1>>12>>23 >>13 s13 ~ 10-3 The same as VMaiani except for the phases of t & b quarks. The imaginary part is O(10-3). This new CKM(Chau-Keung-Maiani) matrix is adapted by PDG as a standard parametrization since 1988.

  6. Some simplified parametrizations • Wolfenstein (’83) used Vcb=0.04  A2,   0.22 Mixing matrix is expressed in terms of , A ~ 0.8,  and . Imaginary part = A3 10-3. However, this matrix is valid only up to 3 • Motivated by the boomerang approach of Frampton & He (’10), Qin & Ma have proposed a different parametrization (’10) Wolfenstein parameters A, ,  QM parameters f, h,  6

  7. The original Wolfenstein parametrization is not adequate for the study of CP violation in charm decays, for example. Hence it should be expanded to higher order of  Wolfenstein parametrization up to 6 Wolfenstein parametrization can also be obtained from KM matrix by making rotations: s s ei, c c ei, b b ei(+), t t e-i(-) and replacing A, , ,  by A’, ’ , ’ and ’

  8. Look quite differently from those of V(CK)Wolf 8 8

  9. Buras et al. (’94): As in any perturbative expansion, high order terms in  are not unique in the Wolfenstein parametrization, though the nonuniquess of the high order terms does not change physics Wolfenstein (’83) used |Vub| ~ 0.2 |Vcb| ~ A3 Now |Vub| ~ 0.00351, |Vcb| ~ 0.0412  |Vub| ~ 2 |Vcb|~ A4 • ~ 0.129,  ~ 0.348 not order of unity ! We define & of order unity 9

  10. Most of the discrepancies are resolved via the definition of the parameters , of order unity • Remaining discrepancies can be alleviated through • Vus =  = ’ • from Vcb • from Vub Ahn, HYC, Oh arXiv:1106.0935 10

  11. Lepton mixing matrix Pontecorvo, Maki, Nakagawa, Sakata 12 = solar  mixing angle, 23 = atmospheric  mixing angle, 13 = reactor  mixing angle A different parametrization has been studied: Huang et al. 1108.3906; 1111.3175 12 ~ 19o, 23 ~ 46o, 13 ~ 29o are quite different from 12 ~ 34o, 23 ~ 38o, 13 ~ 9o

  12. 12 ~ 13o, 23 ~ 2.4o, 13 ~ 0.2o quark: 1>>12>>23 >>13 12 ~ 34o, 23 ~ 38o, 13 ~ 9o lepton:

  13. Baryonic B Decays • B  baryon + antibaryon • B  baryon + antibaryon + meson • B  baryon + antibaryon + 

  14. A baryon pair is allowed in the final state of hadronic B decays. In charm decay, Ds+→pn is the only allowed baryonic D decay. Its BR ~ 10-3 (CLEO)

  15. 2-body charmless baryonic B decays Very rare ! CLEO DLPHI ARGUS CLEO ALEPH CLEO CLEO Belle Belle BaBar Belle 15

  16. CY CZ=Chernyak & Zhitnitsky (’90), CY= Cheng & Yang (’02) What is the theory expectation of Br(B0 pp) ? 16

  17. Talk presented at 7th Particle Physics Phenomenology Workshop, 2007

  18. LHCb (1308.0961) Br(B0 pp)= (1.47+0.62+0.35-0.51-0.14)10-8 Br(Bs0 pp)= (2.84+2.03+0.85-1.08-0.18)10-8 3.3 first evidence see the talk of Prisciandaro (22C1b) LHCb (1307.6165) observed a resonance (1520) in B-ppK- decays Br(B-(1520)p)= (3.9+1.0-0.90.10.3)10-7 (1520)pK- The pQCD calculation of B0 pp is similar to the pQCD calculation of B→cp (46 Feynman diagrams) by X.G.He, T.Li, X.Q.Li, Y.M.Wang (’06) Why is Br(B-(1520)p) >> Br(B0 pp) ?

  19. Angular distribution • Measurement of angular distributions in dibaryon rest frame will provide further insight of the underlying dynamics • SD picture predict a stronger correlation of the meson with the antibaryon than to the baryon in B→B1B2M B-→pp- pp rest frame B rest frame - p u b p - p p B- p - p - u Belle(’08) (’13) p p - p 19

  20. - Angular distribution in penguin-dominated B-ppK- - s u b K- K- s u SD picture predicts a strong correlation between K- and p ! b u p p - - p p u u Belle(’04) Belle: K- is preferred to move collinearly with p in pp rest frame !  a surprise in correlation p p K- _ p BaBar(’05) (’13) BaBar measured Dalitz plot asymmetry unsolved enigma ! 20

  21. Angular distribution in B-p- s b  SD picture: Both  & p picks up energetic s and u quarks, respectively ⇒ on the average, pion has no preference for its correlation with  or p⇒a symmetric parabola that opens downward - B0 p u - u + d Tsai, thesis (’06) _ Belle(’07): M.Z. Wang et al. shows a slanted straight line ⇒another surprise !! p p +  • Correlation enigma occurs in penguin-dominated modes B→ppK, p • Cannot be explained by SD b→ sg* picture • Needs to be checked by LHCb & BaBar • Theorists need to work hard ! 21

  22. Radiative baryonic B decays At mesonic level, bs electroweak penguin transition manifests in BK*. Can one see the same mechanism in baryonic B decays ? • Consider b pole diagram and apply HQS and static b quark limit to relate the tensor matrix element with b form factors • Br(B-p)  Br(B-0-) = 1.210-6 • Br(B-0p)= 2.910-9 Penguin-induced B-p and B-0- should be readily accessible to B factories HYC,Yang (’02) Belle [ Lee & Wang et al. PRL 95, 061802 (’05) ] Br(B-p) = (2.45+0.44-0.380.22)10-6 Br(B-0p) < 4.610-6 first observation of bs in baryonic B decay 22

  23. Extensive studies of baryonic B decays in Taiwan both experimentally and theoretically Theory Expt. Belle group at NTU (Min-Zu Wang,…) Chen, Chua, Geng, He, Hou, Hsiao, Tsai, Yang, HYC,… B-→ppK-: first observation of charmless baryonic B decay (’01) B→pp(K,K*,) →p(,K) →K B→pp, , p (stringent limits) Publication after 2000: (hep-ph) 0008079, 0107110, 0108068, 0110263, 0112245, 0112294, 0201015, 0204185, 0204186, 0208185, 0210275, 0211240, 0302110,0303079, 0306092, 0307307, 0311035, 0405283, 0503264, 0509235, 0511305, 0512335, 0603003, 0603070, 0605127, 0606036, 0606141, 0607061, 0607178, 0608328, 0609133, 0702249, PRD(05,not on hep-ph), 0707.2751, 0801.0022, 0806.1108, 0902.4295, 0902.4831, 1107.0801, 1109.3032, 1204.4771, 1205.0117, 1302.3331 B→p: first observation of b→s penguin in baryonic B decays (’04) Publication after 2002: 15 papers (first author) so far: 7PRL, 2PLB, 6PRD; 2 in preparation Taiwan contributes to 86% of theory papers

  24. Direct CP violation in charm decays

  25. CP violation in charm decays • DCPV requires nontrival strong and weak phase difference • In SM, DCPV occurs only in singly Cabibbo-suppressed decays. It is expected to be very small in charm sector within SM Amp = V*cdVud (tree + penguin) + V*csVus (tree’ + penguin) No CP violation in D decays if they proceed only through tree diagrams Penguin is needed in order to produce DCPV at tree & loop level : strong phase DCPV is expected to be the order of 10-3  10-5 ! 25

  26. Experiment Time-dependent CP asymmetry Time-integrated asymmetry LHCb: (11/14/2011) 0.92 fb-1based on 60% of 2011 data • ACPACP(D0 K+K-) – ACP(D0+-) = - (0.820.210.11)% • 3.5 effect: first evidence of CPV in charm sector CDF: (2/29/2012) 9.7 fb-1 ACP= Araw(K+K-) - Araw(+-)= - (2.330.14)% - (-1.710.15)% = - (0.620.210.10)% 2.7 effect Belle: (ICHEP2012) 540 fb-1 ACP = - (0.870.410.06)% see Mohanty’s talk (11/25) 26

  27. World averages of LHCb + CDF + BaBar + Belle in 2012 aCPdir = -(0.6780.147)%, 4.6 effect aCPind = -(0.0270.163)% Theory estimate is much smaller than the expt’l measurement of |aCPdir |  0.7%  New physics ? 27 27

  28. Chen, Geng, Wang [1206.5158] Delaunay, Kamenik, Perez, Randall [1207.0474] Da Rold, Delaunay, Grojean, Perez [1208.1499] Lyon, Zwicky [1210.6546] Atwood, Soni [1211.1026] Hiller, Jung, Schacht [1211.3734] Delepine, Faisel, Ramirez [1212.6281] Li, Lu, Qin, Yu [1305.7021] Buccella, Lusignoli, Pugliese, Santorelli [1305.7343] Isidori, Kamenik, Ligeti, Perez [1111.4987] Brod, Kagan, Zupan [1111.5000] Wang, Zhu [1111.5196] Rozanov, Vysotsky [1111.6949] Hochberg, Nir [1112.5268] Pirtskhalava, Uttayarat [1112.5451] Cheng, Chiang [1201.0785] Bhattacharya, Gronau, Rosner [1201.2351] Chang, Du, Liu, Lu, Yang [1201.2565] Giudice, Isidori, Paradisi [1201.6204] Altmannshofer, Primulando, C. Yu, F. Yu [1202.2866] Chen, Geng, Wang [1202.3300] Feldmann, Nandi, Soni [1202.3795] Li, Lu, Yu [1203.3120] Franco, Mishima, Silvestrini [1203.3131] Brod, Grossman, Kagan, Zupan [1203.6659] Hiller, Hochberg, Nir [1204.1046] Grossman, Kagan, Zupan [1204.3557] Cheng, Chiang [1205.0580] 28 theory papers ! 28 28

  29. Diagrammatic Approach All two-body hadronic decays of heavy mesons can be expressed in terms of several distinct topological diagrams [Chau (’80); Chau, HYC(’86)] T (tree) A (W-annihilation) E (W-exchange) C (color-suppressed) HYC, Oh (’11) PA, PAEW PE, PEEW P, PcEW S, PEW All quark graphs are topological and meant to have all strong interactions encoded and hence they are not Feynman graphs. And SU(3) flavor symmetry is assumed. 29 29

  30. Cabibbo-allowed decays For Cabibbo-allowed D→PP decays (in units of 10-6GeV) T= 3.14 ± 0.06 (taken to be real) C= (2.61 ± 0.08) exp[i(-152±1)o] E= (1.53+0.07-0.08) exp[i(122±2)o] A= (0.39+0.13-0.09) exp[i(31+20-33)o] CLEO (’10) 2=0.39/d.o.f Rosner (’99) Wu, Zhong, Zhou (’04) Bhattacharya, Rosner (’08,’10) HYC, Chiang (’10) • Phase between C & T ~ 150o • W-exchange Eis sizable with a large phase  importance of 1/mcpower corrections • W-annihilaton A is smaller than Eand almost perpendicular to E E C A T The great merit & strong point of this approach  magnitude and strong phase of each topological tree amplitude are determined 30

  31. Tree-level direct CP violation DCPV can occur even at tree level A(Ds+ K0+) =d(T + Pd+ PEd) + s(A + Ps+ PEs), p=V*cpVup DCPV in Ds+ K0+ arises from interference between T & A  10-4 DCPV at tree level can be reliably estimated in diagrammatic approach as magnitude & phase of tree amplitudes can be extracted from data Larger DCPV at tree level occurs in decay modes with interference between T & C (e.g. Ds+K+) or C & E (e.g. D00) 31

  32. Tree-level DCPV aCP(tree) in units of per mille 10-3 > adir(tree) > 10-4 Largest tree-level DCPV PP: D0K0K0, VP: D0’ aCP(tree) vanishes in D0+-, K+K- 32

  33. Short-distance penguin contributions are very small. How about power corrections to QCD penguin ? SD weak penguin annihilation is also very small; typically, PE / T  0.04 and PA / T  -0.02 Large LD contribution to PE can arise from D0 K+K- followed by a resonantlike final-state rescattering It is reasonable to assume PE ~ E, PEP ~ EP, PEV ~ EV Power corrections to P from PE via final-state rescattering cannot be larger than T

  34. aCPdir (10-3) aCPdir= -0.1390.004% (I) -0.1510.004% (II) about 3.3 away from -(0.6780.147)% A similar result aCPdir=-0.128% obtained by Li, Lu, Yu see Hsiang-nan Li’s talk (11/25) Even for PE  T aCPdir = -0.27%, an upper bound in SM If aCPdir ~ -0.68%, it is definitely a new physics effect ! 34

  35. Attempts for SM interpretation Golden, Grinstein (’89): hadronic matrix elements enhanced as in I=1/2 rule. However, D data do not show large I=1/2 enhancement over I=3/2 one. Moreover, |A0/A2|=2.5 in D decays is dominated by tree amplitudes. Brod, Kagan, Zupan: PE and PA amplitudes considered Pirtskhalava, Uttayarat : SU(3) breaking with hadronic m.e. enhanced Bhattacharya, Gronau, Rosner : Pb enhanced by unforeseen QCD effects Feldmann, Nandi, Soni : U-spin breaking with hadronic m.e. enhanced Brod, Grossman, Kagan, Zupan: penguin enhanced Franco, Mishima, Silvestrini: marginally accommodated We have argued that power corrections to P from PE via final-state rescattering cannot be larger than T

  36. LHCb in 2013: ACP = - (0.340.150.10)% D* tagged ACP = (0.490.300.14)% B D0X, muon tagged - (0.150.16)% combination See D. Tonelli’s talk (11/25) World average: aCPdir = -(0.3330.120)%, 2.8 aCPind = (0.0150.052)% Recall that aCPdir = -(0.6780.147)%, 4.6 in 2012 ! It appears that SM always wins !

  37. Direct CP violation in charmless B decays

  38. Direct CP asymmetries (2-body) LHCb AKACP(K-0) – ACP(K-+) K puzzle: AK is naively expected to vanish 38 38

  39. ACP(B- K-) Expt: Theory: LHCb observed CP violation in B-K-K+K- but not around  resonance arXiv:1306.1246 LHCb (1309.3742) obtained ACP = (2.22.10.9)%

  40. In heavy quark limit, decay amplitude is factorizable, expressed in terms of form factors and decay constants. sign See Beneke & Neubert (’03) for mb results 40 40

  41. A(B0K-+) ua1+c(a4c+ra6c) Im4c  0.013  wrong sign for ACP 4c charming penguin, FSI penguin annihilation 1/mb corrections penguin annihilation 41

  42. New CP puzzles in QCDF Penguin annihilation solves CP puzzles for K-+,+-,…, but in the meantime introduces new CP puzzles for K-, K*0, … Also true in SCET with penguin annihilation replaced by charming penguin 42 42 42

  43. All “problematic” modes receive contributions from uC+cPEW PEW  (-a7+a9), PcEW  (a10+ra8), u=VubV*us, c=VcbV*cs AK puzzle can be resolved by having a large complex C (C/T  0.5e–i55 ) or a large complex PEW or the combination AK 0 if C, PEW, A are negligible  AK puzzle o Large complex C Charng, Li, Mishima; Kim, Oh, Yu; Gronau, Rosner; … Large complex PEW needs New Physics for new strong & weak phases Yoshikawa; Buras et al.; Baek, London; G. Hou et al.; Soni et al.; Khalil et al;… 43

  44. The two distinct scenarios can be tested in tree-dominated modes where ’cPEW << ’uC. CP puzzles of -, 00 & large rates of 00, 00 cannot be explained by a large complex PEW 00 puzzle: ACP=(4324)%, Br = (1.910.22)10-6 44 44

  45. Direct CP asymmetries (3-body) LHCb found evidence of inclusive CP asymmetry in B-+--, K+K-K-, K+K-- Large asymmetries observed in localized regions of p.s. ACP(KK) = -0.6480.0700.0130.007 for mKK2 <1.5 GeV2 ACP(KKK) = -0.2260.0200.0040.007 for 1.2< mKK, low2 <2.0 GeV2, mKK, high2 <15 GeV2 ACP() = 0.584+0.082+0.027+0.007 for m, low2 <0.4 GeV2, m, high2 > 15 GeV2 ACP(K) = 0.6780.0780.0320.007 for 0.08< m, low2 <0.66 GeV2, mK2 <15 GeV2 45

  46. Correlation: ACP(K-K+K-)  – ACP(K-+-), ACP(-K+K-)  – ACP(-+-) • Relative signs between CP asymmetries of K-K+K- & -+-, -K+K- & K-+- are consistent with U-spin prediction. • It has been conjectured that CPT theorem & final-state rescattering of +- K+K- may play important roles Zhang, Guo, Yang [1303.3676] Bhattacharya, Gronau, Rosner [1306.2625] Xu, Li, He [1307.7186] Bediaga, Frederico, Lourenco [1307.8164] Cheng, Chua [1308.5139] Zhang, Guo, Yang [1308.5242] Lesniak, Zenczykowski [1309.1689] Xu, Li, He [1311.3714]

  47. Conclusion of this section • CP asymmetries are the ideal places to discriminate between different models. • In QCDF one needs two 1/mb power corrections (one to penguin annihilation, one to color-suppressed tree amplitude) to explain decay rates and resolve CP puzzles • Can we understand the correlation ? ACP(K-K+K-)  – ACP(K-+-), ACP(-K+K-)  – ACP(-+-)

  48. Conclusions • To expand Wolfenstein parametrization to higher order of , it is important to use  &  parameters order of unity. • First evidence of charmless baryonic B decays: time for updated theory studies. Correlation puzzle in penguin-dominated decays needs to be resolved. • DCPV in charm decays is studied in the diagrammatic approach. It can be reliably estimated at tree level. Our prediction is aCP = -(0.1390.004)%

  49. Backup Slides

  50. : strong phase To accommodate aCP one needs P/T~ 3 for maximal strong phase, while it is naively expected to be of order s/ Bhattacharya, Gronau, Rosner Brod, Grossman, Kagan, Zupan Can penguin be enhanced by some nonperturbative effects or unforeseen QCD effects ? We have argued that power corrections to P from PE via final-state rescattering cannot be larger than T 50

More Related