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Title: Flavor and CP violation with fourth generations revisited

Journal Article · · Physical Review. D, Particles Fields
 [1];  [1]
  1. Department of Physics, National Taiwan University, Taipei, Taiwan 10617 (China)

The standard model predicts a very small CP violation phase sin2{Phi}{sub B{sub s}{sup SM{approx_equal}}-0.04 in B{sub s}}-B{sub s} mixing. Any finite value of {Phi}{sub B{sub s}} measured at the Tevatron would imply new physics. With recent hints for finite sin2{Phi}{sub B{sub s}}, we reconsider the possibility of a fourth generation. As recent direct search bounds have become considerably heavier than 300 GeV, we take the t{sup '} mass to be near the unitarity bound of 500 GeV. Combining the measured values of {Delta}m{sub B{sub s}} with B(B{yields}X{sub s}l{sup +}l{sup -}), together with typical f{sub B{sub s}} values, we find a sizable sin2{Phi}{sub B{sub s}}{sup SM4}{approx}-0.33. Using m{sub b}{sup '}=480 GeV, we extract the range 0.06<|V{sub t}{sup '}{sub b}|<0.13 from the constraints of {Gamma}(Z{yields}bb), {Delta}m{sub D}, and B(K{sup +}{yields}{pi}{sup +}{nu}{nu}). This illustrates how the 4x4 mixing matrix can be determined in the future, once m{sub t}{sup '} and m{sub b}{sup '} are known. A crucial future measurement would be B(K{sub L{yields}{pi}}{sup 0{nu}{nu}}), which would determine V{sub t}{sup '}{sub d}.

OSTI ID:
21432912
Journal Information:
Physical Review. D, Particles Fields, Vol. 82, Issue 3; Other Information: DOI: 10.1103/PhysRevD.82.036002; (c) 2010 American Institute of Physics; ISSN 0556-2821
Country of Publication:
United States
Language:
English