arXiv subjects

N. Nemkov

Publications and source records attributed to N. Nemkov.

2 recordsLinked to original sources

arXiv2013

S-duality as Fourier transform for arbitrary $ε_1,ε_2$

The AGT relations reduce S-duality to the modular transformations of conformal blocks. It was recently conjectured that for the four-point conformal block the modular transform up to the non-perturbative contributions can be written in form of the ordinary Fourier transform when $β\equiv-ε_1/ε_2=1$. Here we extend this conjecture to general values of $ε_1,ε_2$. Namely, we argue that for a properly normalized four-point conformal block the S-duality is perturbatively given by the Fourier transform for arbitrary values of the deformation parameters $ε_1,ε_2$. The conjecture is based on explicit perturbative computations in the first few orders of the string coupling constant $g^2\equiv-ε_1ε_2$ and hypermultiplet masses.

hep-th↗

arXiv2012

Heavy-meson physics and flavour violation with a single generation

We study flavour-violating processes which involve heavy B- and D-mesons and are mediated by Kaluza-Klein modes of gauge bosons in a previously suggested model where three generations of the Standard Model fermions originate from a single generation in six dimensions. We find the bound on the size R of the extra spatial dimensions 1/R>3.3 TeV, which arises from the three-body decay B_s to K mu e. Due to the still too low statistics this bound is much less stringent than the constraint arising from K to mu e, 1/R>64 TeV, which was found in a previous work (Frere et al., JHEP, 2003). Nevertheless, we argue that a clear signature of the model would be an observation of K to mu e and B_s to K mu e decays without observations of other flavour and lepton number changing processes at the same precision level.

hep-ph↗