B s → ϕl + l − decays in the topcolor-assisted technicolor model

Abstract

Using the updated form factors within the light-cone QCD sum rule approach, we calculate the new physics contributions to rare semileptonicB s → φµ + µ − , φτ + τ − decays from the new particles appearing in the topcolor-assisted technicolor (TC2) model. In our evaluations, we find that: (i) the branching ratio, normalized forward-backward asymmetry and lepton polarization asymmetries show highly sensitivity to charged top-pions contributions and little sensitivity to Z ′ contributions. The TC2 enhancements to the branching ratios of these decays can reach a factor of ∼ 2; (ii) the NP enhancement to the forward-backward asymmetry of the decay B s → φµ + µ − is in the range −13% to 3%, but −9% to −6% for decay B s → φτ + τ − compared to the SM predictions; (iii) the TC2 model provide an enhancement of about 12% to the longitudinal polarization asymmetry P L for decay B s → φµ + µ − , but a decrease of about 10% to the transverse polarization asymmetry P T for the decay B s → φτ + τ − .

Colloquium: Heat flow and thermoelectricity in atomic and molecular junctions

“…For instance, Pop et al (Pop et al, 2006) have used high currents to induce heating in a single-walled carbon nanotube, with a model to relate the current-voltage (I-V) characteristics to the high-temperature thermal conductance. In another example, the so-called 3ω method (Cahill, 1990;Lu et al, 2001), was used to study nanotubes (Bourgeois et al, 2007;Choi et al, 2005Choi et al, , 2006. In this method, an a.c. current is applied to the sample which also acts as a heater.…”

“…The thermal conductance of nanowires made of, e.g., Si, Ge and GaAs was studied by several authors (Mingo and Yang, 2003;Mingo et al, 2003;Tanaka et al, 2005;. Much attention has been given to carbon-based structures, such as carbon nanotubes, graphene and graphite (Lan et al, 2009;Lü and Wang, 2008;Mingo and Broido, 2005a,b;Yamamoto and Watanabe, 2006;Yamamoto et al, 2004;Zhang and Li, 2005;Zimmermann et al, 2008). Another example is the recent study of isotope and disorder effects (Murphy and Moore, 2007), specifically in carbon and boron-nitride nanotubes (Savić et al, 2008a,b;Stewart et al, 2009).…”

“…(6) (or its equivalent form for fermions). Manybody perturbation expansions to compute these Green's functions have been performed for simple model Hamiltonians (Galperin et al, 2007a;Lü and Wang, 2007) but it is no easy task to introduce interactions (beyond mean field) in realistic systems.…”