We calculate the most interesting rare and CP-violating K and B decays in the Littlest Higgs model with T-parity. We give a collection of Feynman rules including v(2)/f(2) contributions that are presented here for the first time and could turn out to be useful also for applications outside flavour physics. We adopt a model-independent parameterization of rare decays in terms of the gauge independent functions X-i, Y-i, Z(i) (i = K, d, s), which is in particular useful for the study of the breaking of the universality between K, B-d and B-s systems through non-MFV interactions. Performing the calculation in the unitary and 't Hooft-Feynman gauge, we find that the final result contains a divergence which signals some sensitivity to the ultraviolet completion of the theory. Including an estimate of this contribution, we calculate the branching ratios for the decays K+ -> pi(+)nu(nu) over bar, K-L -> pi(0)nu(nu) over bar, B-s,B-d -> mu(+) mu(-), B -> X-s,X-d nu(nu) over bar, K-L -> pi(0) l(+) l(-) and B -> X-s,X-d l(+) l(-), paying particular attention to non-MFV contributions present in the model. The main feature of mirror fermion effects is the possibility of large modifications in rare K decay branching ratios and in those B decay observables, like S A A and As SL, that are very small in the SM. Imposing all available constraints we find that the decay rates for B-s,B-d -> mu(+) mu(-) and B -> X-s,X-d nu(nu) over bar can be enhanced by at most 50% and 35% relative to the SM values, while Br(K+ -> pi(+)nu(nu) over bar) and Br(K-L -> pi(0)nu(nu) over bar) can be both as high as 5 (.) 10(-10). Significant enhancements of the decay rates K-L -> pi(0) l(+) l(-) are also possible. Simultaneously, the CPasymmetries S-psi phi and A(SL)(s) can be enhanced by an order of magnitude, while the electroweak penguin e r ects in B -> K turn out to be small, in agreement with the recent data.

Blanke, M., Buras Andrzej, J., Poschenrieder, A., Recksiegel, S., Tarantino, C., Uhlig, S., et al. (2007). Rare and CP-violating K and B decays in the littlest Higgs model with T-parity. JOURNAL OF HIGH ENERGY PHYSICS(1) [10.1088/1126-6708/2007/01/066].

Rare and CP-violating K and B decays in the littlest Higgs model with T-parity

TARANTINO, CECILIA;
2007-01-01

Abstract

We calculate the most interesting rare and CP-violating K and B decays in the Littlest Higgs model with T-parity. We give a collection of Feynman rules including v(2)/f(2) contributions that are presented here for the first time and could turn out to be useful also for applications outside flavour physics. We adopt a model-independent parameterization of rare decays in terms of the gauge independent functions X-i, Y-i, Z(i) (i = K, d, s), which is in particular useful for the study of the breaking of the universality between K, B-d and B-s systems through non-MFV interactions. Performing the calculation in the unitary and 't Hooft-Feynman gauge, we find that the final result contains a divergence which signals some sensitivity to the ultraviolet completion of the theory. Including an estimate of this contribution, we calculate the branching ratios for the decays K+ -> pi(+)nu(nu) over bar, K-L -> pi(0)nu(nu) over bar, B-s,B-d -> mu(+) mu(-), B -> X-s,X-d nu(nu) over bar, K-L -> pi(0) l(+) l(-) and B -> X-s,X-d l(+) l(-), paying particular attention to non-MFV contributions present in the model. The main feature of mirror fermion effects is the possibility of large modifications in rare K decay branching ratios and in those B decay observables, like S A A and As SL, that are very small in the SM. Imposing all available constraints we find that the decay rates for B-s,B-d -> mu(+) mu(-) and B -> X-s,X-d nu(nu) over bar can be enhanced by at most 50% and 35% relative to the SM values, while Br(K+ -> pi(+)nu(nu) over bar) and Br(K-L -> pi(0)nu(nu) over bar) can be both as high as 5 (.) 10(-10). Significant enhancements of the decay rates K-L -> pi(0) l(+) l(-) are also possible. Simultaneously, the CPasymmetries S-psi phi and A(SL)(s) can be enhanced by an order of magnitude, while the electroweak penguin e r ects in B -> K turn out to be small, in agreement with the recent data.
2007
Blanke, M., Buras Andrzej, J., Poschenrieder, A., Recksiegel, S., Tarantino, C., Uhlig, S., et al. (2007). Rare and CP-violating K and B decays in the littlest Higgs model with T-parity. JOURNAL OF HIGH ENERGY PHYSICS(1) [10.1088/1126-6708/2007/01/066].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/153764
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