Jul 20 – 27, 2011
Alpes Congrès - Alpexpo
Europe/Paris timezone

Measuring 4th generation CKM parameters at the LHC

Not scheduled
Dauphine (Alpes Congrès - Alpexpo)


Alpes Congrès - Alpexpo

Poster Flavour Physics and Fundamental Symmetries


Prof. George W.S. Hou (National Taiwan University)


CPV measurment in Bs -> J/psi phi at the Tevatron, sin2Phi_Bs, hint at new physics, with the 4th generation the simplest explanation. At the same time, great progress is made already at the LHC for the direct search of 4th generation quarks. We show that a precise measurement of sin2Phi_Bs by LHCb, together with a measurement (combining LHCb, ATLAS and CMS) of Bs -> mu+mu- at slightly above the SM level, normalized with Bs-mixing, can pin down the strength and phase of Vt's^*Vt'b for given mt'. This could be achieved as early as 2012. Such a measurement is akin to the measurement of sin2phi1/beta by Belle and BaBar in 2001, i.e. completing a CKM triangle, but the strength of CPV, unlike the 3 generation case, could be linked to the baryon asymmetry of the Universe. A complementary measurement would be to measure Vt'b, by measuring the branching ratio (BR) of the kinematic suppressed, but CKM allowed, t' -> b'W^* decay. The knowledge that |mt' - mb'| < MW implies that the W here is virtual. Precisely when Vt'b is small, the BR for t' -> b'W^* can be amplified, making it a sensitive probe of small values of Vt'b.

Primary author

Prof. George W.S. Hou (National Taiwan University)

Presentation materials