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4th Generation b’ and t’ Decays and CP Violation

4th Generation b’ and t’ Decays and CP Violation. April 28, 2006, HEP Seminar @ IoPAS. Outline. Intro Original starting point — t  cX Why not b’, t’ themselves ? Digression: Problems with 4th generation — The jury is out … Find, or Rule Out @ LHC

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4th Generation b’ and t’ Decays and CP Violation

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  1. 4th Generation b’ and t’ Decays and CP Violation April 28, 2006, HEP Seminar @ IoPAS

  2. Outline • Intro • Original starting point — t cX • Why not b’, t’ themselves ? • Digression: Problems with 4th generation —The jury is out … • Find, or Rule Out @ LHC • Hints from B, and Predictions • Hints: AK+p --AK+p 0; DSf • Predictions: CPV in Bs mixing; ; [more • FCNC t cX Decays • b’, t’ Decays • mQ dependence; width • b’ bX; t’ tX; • CPV inb’ sX • Conclusion 11 11 2 13 Strategy at LHC w/ A. Arhrib, hep-ph/0602035

  3. Introduction

  4. Original starting point — t cX SM3 prediction Mele, Petrarca, Soddu, PLB 1998 correcting Eilam, Hewett, Soni, PRD1991 • Very strong GIM cancellation btwn d, s, b • Unsuppressed top width How to Enhance ? LHC Sensitivity Tevatron Run II So, last summer started a ho-hum project. But study find t cZ can only reach 10-6, and stretched at that ... Late summer realized: Timely for the LHC. Why not b’, t’ themselves ?

  5. Digression: Problems with 4th generation • Particle mass ~ EW scale Natural: • W, Z, H; top the only fermion, so … • Nn = 3, ca. 1989: b’ stock collapsed …

  6. eV Seesaw and 4th Generation? WSH, Soddu, hep-ph/0512278 • 4th generation? — The jury is out … • Particle mass ~ EW scale Natural: • W, Z, H; top the only fermion, so … • Nn = 3, ca. 1989: b’ stock collapsed … • Well, now neutrino has mass Something extra out there

  7. eV Seesaw

  8. eV Seesaw w/ 4th Generation? 8 x 8 corrections 4 x 4 ε small Pseudo-Dirac (4th) Neutral Lepton N Remainder: “3 + 3” Neutrino Model

  9. 4th generation? — The jury is out … • Particle mass ~ EW scale Natural: • W, Z, H; top the only fermion, so … • Nn = 3, ca. 1989: b’ stock collapsed … • Well, now neutrino has mass Something extra out there • Trouble with S parameter (PDG04)

  10. PDG04 (2003) J. Erler and P. Langacker hep-ph/0407097

  11. 4th generation? — The jury is out … • Particle mass ~ EW scale Natural: • W, Z, H; top the only fermion, so … • Nn = 3, ca. 1989: b’ stock collapsed … • Well, now neutrino has mass Something extra out there • Trouble with S parameter (PDG04) • - Possible if neutral lepton N relatively light, mN ~ 55 GeV • (Maltoni,) Novikov, Okun, Razanov, Vysotsky • - PDG: Direct b’/t’ search; Unitarity (CKM) listings anyhow • S, T Shift: 2003  2005 (ADLOS)

  12. (2003) ADLOS’05 hep-ex/0509008 (2005) 2s shift in BOTH S and T  Positive A 4th generation could still be alive, and if yes it will appear soon

  13. 4th generation? — The jury is out … • Particle mass ~ EW scale Natural: • W, Z, H; top the only fermion, so … • Nn = 3, ca. 1989: b’ stock collapsed … • Well, now neutrino has mass Something extra out there • Trouble with S parameter (PDG04) ? • - Possible if neutral lepton N relatively light, mN ~ 55 GeV • (Maltoni,) Novikov, Okun, Razanov, Vysotsky • - PDG: Direct b’/t’ search; Unitarity (CKM) listings • S, T Shift: 2003  2005 (ADLOS) • EW Dr: |mt’ –mb’ | ≲ MW In era of LHC, can Directly Search for b’, t’ Once and For All !

  14. 4th generation? — The jury is out … In era of LHC, can Directly Search for b’, t’ Once and For All ! Find b’, t’, or Rule Out @ LHC It’s a Duty.

  15. b sCPV Phenomena Is Current NP Frontier • Sfinb sqq • AK+p--AK+p0 Puzzle Two Hints Can Both Arise from PEW w/ 4th Generation ? Seemingly Yes.

  16. Parameterization for B (’n K; ’nb’) WSH, Soni, Steger 1987 SM3 s← b 3 new angles, 2 new CPVphases

  17. b  sg well satisfied ACP(K+p-) ~ -0.12, ACP(K+p0) ~ +0.04 ? WSH, Nagashima, Soddu, PRL’05 From Constraints • Some parameter space allowed • fsb~ +p/2 favored by • both ACP(K+p0) • and ⊕

  18. SfK0, SK0p0 hep-ph/0603097 WSH, Nagashima, Raz, Soddu Right trend forSpK, SfK QCDF NLO s3 PQCD LO NF (QCDF-LO)

  19. Predictions

  20. and Prospects Could Tevatron Measure These !? Just Around Corner! (SM3-like) Phase ~ -0.2 to -0.7! Defintely BSM if measured !

  21. Extra !! CDF Sees ! of course Makiko and Andrea and WSH are writing ...

  22. and Prospects Tevatron Measured This ! SM3-like Phase ~ -0.2 to -0.7! Defintely BSM if measured ! Can Tevatron Measure This ?

  23. Large and Kaons: Enhanced WSH, Nagashima, Soddu, PRD’05

  24. b  d impose From b → s study Parameterization for B’s (& K’s) WSH, Soni, Steger 1987 SM3 We need to deal with mixing matrix in detail to keep Unitarity b  s Kaon

  25. (E. Pallante et al.) (J. Bijnens et al.) well-satisfy ! Constrain s  dfrom K Physics (shaded) “Standard” No SM3 solution Therefore….

  26. well-satisfy vs Vub ~ 0.01e-ig Hard to tell apart (non-trivial) with present precision ∵ stringent s d

  27. Implication for Current E391A U.L. Grossman-Nir Very hard to measure enhanced to or even higher !! In general larger than !! SM 3 Rate enhanced up to almost two orders !! ∵ Large CPV Phase

  28. x ~ 0.22 “Typical” CKM Matrix Double Cabibbo Large/Imaginary

  29. FCNC t  cX Decays Arhrib, WSH, hep-ph/0602035

  30. In era of LHC, can Directly Search for b’, t’ Once and For All ! Of order 102 pb • Discovery at LHC not a problem ! • Interest in FCNC Decays. Benchmark Sensitivity for Top For b’, t’, scale by cross section (but increased event complexity)

  31. c t i = d, s, b, b’ Z, H, g, g t  cX Effectively 0 Symbolic: FeynArts, FormCalc Numeric: LoopTools, FF SM Result Effective 2 gen. ⇨No hope for CPV • Enhanced by Orders of Magnitude • w.r.t. SM3 ≲ 10-13 Still out of Expt’l reach !

  32. b’, t’ Decays How to search at LHC Arhrib, WSH, hep-ph/0602035

  33. Charged current Tree level decay Full analytic treatment of off-shell W* Loop almost the same strength Good approximation for ( ) Good approximation because d, s, b practically 0 ⇨Again no hope for CPV

  34. mQ dependence: b’  b X Internal: mt, mt’ External: mb’ from dr constraint decoupling GIM b’  tW External Internal

  35. t t’ i = d, s, b, b’ Z, H, g, g mQ dependence : t’  t X Internal: mb’ External: mt, mt’ from dr constraint External Internal

  36. b’ width (in GeV) t’ width (in GeV) mQ dependence: Rich Pattern • For illustration, shall typically use: • mt’= 300 GeV • w/ mb’= 240 GeV for mb’ <mt’ • 360 GeV for mb’ >mt’ • for sizable • for suppressed Width could be suppressed, but does not vanish

  37. b’ Decays and b’  bFCNC Sizable b’  cW dominance b’  tW dominance FCNC 10-5 - 10-2 10-4 - 10-3 Rarity comparable to b

  38. b’ Decays and b’  bFCNC Suppressed suppress by lower mb’ b’  tW* dominance b’  tW dominance FCNC 10-2 - 10-1 10-4 - 10-3 mt+MW = 255 GeV Lighter b’: FCNC could still dominate ~ b’  cW possible

  39. Initial discovery should consider b’  cW ~ b’  bZ, bH ~b’  tW* For mb’ > mt+MW = 255 GeV b’  tW dominance; FCNC searchable b’ Signatures For mb’ < mt+MW = 255 GeV b’  cW dominance b’  tW* dominance for sizable for suppressed Kinematic suppressed for mb’≲ 230 GeV Bonus !! cc(bar)WW; cWbZ; cWbH; tc(bar)WW*; tt(bar)W*W*; tW*bZ; tW*bH; Rich Signature 4 W’s + 2b’s tt(bar)WW → bb(bar)W+W-W+W-

  40. Comment: Tevatron Run II? Oliveira and Santos, PRD’03 following Arhrib & WSH, PRD’01 Quite open at Tevatron Run II, punished by dropping cross section Will they do it ?

  41. t’ Decays: t’ →bW Dominance t’  tFCNC Less Interesting than b’, but can be probed 10-5 - 10-3 10-6 10-5 - 10-3

  42. t’ Signature t’ →bW Dominance Always FCNC searchable bb(bar)W+W- Like a Heavy Top

  43. In era of LHC, can Directly Search for b’, t’ Once and For All ! Of order 102 pb • Discovery at LHC not a problem ! • Interest in FCNC Decays. • Has to be done ! Why Don’t WE Do it !? • b’: ~ 200 – 240 GeV most interesting (FCNC b’  b Dom.) • otherwise likely b’  cW (or b’  tW(*)) dominance • [measure FCNC later … • t’: Like a Heavy Top —— t’  bW dominance b’  bH Fish! N.B. Both b’ < t’ or b’ > t’ possible

  44. N.B. CP inv. Phase computable ! Extract Weak Phase. b’  sXFCNC: CP Violation ! Example: From b  s and s  d Study of WSH, Nagashima, Soddu Not Optimized for CPV. Could be Larger! BR strongly dep. on Vcb’ Lighter b’, below 250 GeV, Very Interesting ! Arhrib, WSH, in progress

  45. Sfinb sqq • AK+p --AK+p 0Puzzle Hints Conclusions 4th Generation is All Encompassing As far as Flavor is concerned. • At LHC • b’ Signatures Low mass ⇨ Initial Discovery b’  tW Open cc(bar)WW; cWbZ; cWbH; tc(bar)WW*; tt(bar)W*W*; tW*bZ; tW*bH; bb(bar)W+W-W+W- Higgs Bonus bb(bar)W+W- • t’ Signature: Heavy “Top” • FCNC b’  sXcan exhibit CP Violation ! In principle measure CPV Phase.

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