2496873
Complete low-energy effective action in N=4 SYM: A Direct N=2 supergraph calculation
Using the covariant N=2 harmonic supergraph techniques we calculate the one-loop low-energy effective action of N=4 super-Yang–Mills theory in Coulomb branch with gauge group SU(2) spontaneously broken down to U(1). The full dependence of the low-energy effective action on both the hypermultiplet and gauge fields is determined. The direct quantum calculation confirms the correctness of the exact N=4 SYM low-energy effective action derived in hep-th/0111062 on the purely algebraic ground by invoking a hidden N=2 supersymmetry which completes the manifest N=2 one to N=4. Our results provide an exhaustive solution to the problem of finding out the exact completely N=4 supersymmetric low-energy effective action for the theory under consideration.
118435943
Equivalence between supersymmetric self-dual and Maxwell–Chern–Simons models coupled to a matter spinor superfield
Abstract We study the duality of the supersymmetric self-dual and Maxwell–Chern–Simons theories coupled to a fermionic matter superfield, using a master action. This approach evades the difficulties inherent to the quartic couplings that appear when matter is represented by a scalar superfield. The price is that the spinorial matter superfield represents a unusual supersymmetric multiplet, whose main physical properties we also discuss.
119195088
Effective superpotential in the generic higher-derivative superfield supersymmetric three-dimensional gauge theory
We formulate a generic three-dimensional superfield higher-derivative gauge theory coupled to the matter, which, in certain cases reduces to the three-dimensional scalar super-QED, or supersymmetric Maxwell-Chern-Simons or Chern-Simons theories with matter. For this theory, we explicitly calculate the one-loop effective potential.
118365576
Effective superpotential in the generic higher-derivative three-dimensional scalar superfield theory
We formulate a generic three-dimensional higher-derivative superfield theory for self-interacting scalar superfield action. We consider the cases of real and complex scalar superfields. For these theories, we explicitly calculate the one-loop effective potential.
119277679
Four-dimensional aether-like Lorentz-breaking QED revisited and problem of ambiguities
In this paper, we consider the perturbative generation of the CPT-even aether-like Lorentz-breaking term in the extended Lorentz-breaking QED within different approaches and discuss its ambiguities.
118338237
Supersymmetric extensions of k-field models
Abstract We investigate the supersymmetric extension of k-field models, in which the scalar field is described by generalized dynamics. We illustrate some results with models that support static solutions with the standard kink or the compact profile.
9655654
Higgs sector of the left-right model with explicit CP violation
We explore the Higgs sector of the Minimal Left-Right (LR) Model based on the gauge group $SU(2{)}_{L}\ifmmode\times\else\texttimes\fi{}SU(2{)}_{R}\ifmmode\times\else\texttimes\fi{}U(1{)}_{B\ensuremath{-}L}$ with explicit $CP$ violation in the Higgs potential. Since flavour-changing neutral current experiments and the small scale of neutrino masses both place stringent constraints on the Higgs potential, we seek to determine whether minima of the Higgs potential exist that are consistent with current experimental bounds. We focus on the case in which the right-handed symmetry-breaking scale is only moderately large, of order 15\char21{}50 TeV. Unlike the case in which the Higgs potential is $CP$-invariant, the $CP$ noninvariant case does yield viable scenarios, although these require a small amount of fine-tuning. We consider a LR model supplemented by an additional $U(1)$ horizontal symmetry, which results in a Higgs sector consistent with current experimental constraints and a realistic spectrum of neutrino masses.
117694102
B0 anti-B0 mixing beyond factorization
We present a calculation of the B°-B° mixing matrix element in the framework of QCD sum rules for three-point functions. We compute α s corrections to a three-point function at the three-loop level in QCD perturbation theory, which allows one to extract the matrix element with next-to-leading order (NLO) accuracy. This calculation is imperative for a consistent evaluation of experimentally measured mixing parameters since the coefficient functions of the effective Hamiltonian for B 0 -B 0 mixing are known at NLO. We find that radiative corrections violate factorization at NLO; this violation is under full control and amounts to 10%. The resulting value of the B parameter is found to be B B (m b ) = 1 + 0.1 P T - 0.05 n o n - P T .
118688648
Lepton flavor-violating transitions in effective field theory and gluonic operators
Lepton flavor-violating processes offer interesting possibilities to probe new physics at multi-TeV scale. We discuss those in the framework of effective field theory, emphasizing the role of gluonic operators. Those operators are obtained by integrating out heavy quarks that are kinematically inaccessible at the scale where low-energy experiments take place and make those experiments sensitive to the couplings of lepton flavor-changing neutral currents to heavy quarks. We discuss constraints on the Wilson coefficients of those operators from the muon conversion ${\ensuremath{\mu}}^{\ensuremath{-}}+(A,Z)\ensuremath{\rightarrow}{e}^{\ensuremath{-}}+(A,Z)$ and from lepton flavor-violating tau decays with one or two hadrons in the final state, e.g., $\ensuremath{\tau}\ensuremath{\rightarrow}\ensuremath{\ell}{\ensuremath{\eta}}^{(\ensuremath{'})}$ and $\ensuremath{\tau}\ensuremath{\rightarrow}\ensuremath{\ell}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ with $\ensuremath{\ell}=\ensuremath{\mu},e$. To illustrate the results we discuss explicit examples of constraining parameters of leptoquark models.
19200788
Final state rescattering as a contribution to B->rho gamma
We provide a new estimate of the long-distance component to the radiative transition B{r_arrow}{rho}{gamma}. Our mechanism involves the soft scattering of on-shell hadronic products of nonleptonic B decay, as in the chain B{r_arrow}{rho}{rho}{r_arrow}{rho}{gamma}. We employ a phenomenological fit to scattering data to estimate the effect. The specific intermediate states considered here modify the B{r_arrow}{rho}{gamma} decay rate at roughly the 5{minus}8{percent} level, although the underlying effect has the potential to be larger. Contrary to other mechanisms of long distance physics which have been discussed in the literature, this yields a non-negligible modification of the B{sup 0}{r_arrow}{rho}{sup 0}{gamma} channel and hence will provide an uncertainty in the extraction of V{sub td}. This mechanism also affects the isospin relation between the rates for B{sup {minus}}{r_arrow}{rho}{sup {minus}}{gamma} and B{sup 0}{r_arrow}{rho}{sup 0}{gamma} and may generate CP asymmetries at experimentally observable levels. {copyright} {ital 1997} {ital The American Physical Society}
16727874
Spectator effects and lifetimes of heavy hadrons
We present a calculation of subleading 1/m{sub b} corrections to spectator effects in the ratios of beauty hadron lifetimes in heavy-quark expansion. We find that these effects are sizable and should be taken into account in systematic analyses of heavy hadron lifetimes. In particular, the inclusion of 1/m{sub b} corrections brings into agreement the theoretical predictions and experimental observations of the ratio of lifetimes of {lambda}{sub b} baryon and B{sub d} meson. We obtain {tau}(B{sub u})/{tau}(B{sub d})=1.06{+-}0.02, {tau}(B{sub s})/{tau}(B{sub d})=1.00{+-}0.01, {tau}({lambda}{sub b})/{tau}(B{sub d})=0.86{+-}0.05.