209835249
f(R)-Brane
Abstract We investigate the existence of brane solutions in braneworld scenarios described by real scalar field in the presence of modified f ( R ) gravity with a single extra dimension. In the case of constant curvature, we obtain first-order differential equations which solve the equations of motion and ease the search for explicit analytical solutions. Several examples of current interest are investigated to illustrate the results of the present work.
119211852
Lorentz violation and the proper-time method
Abstract In this Letter, we apply the proper-time method to generate the Lorentz-violating Chern–Simons terms in the four-dimensional Yang–Mills and non-linearized gravity theories. It is shown that the coefficient of the induced Chern–Simons term is finite but regularization dependent.
96444982
Horava-Lifshitz-like extensions of supersymmetric theories
Within the superfield approach, we formulate two different extensions of the Wess-Zumino model and super-QED with Horava-Lifshitz-like additive terms, discuss their quantum properties and calculate lower contributions to the effective action. In the case of the gauge theory, the one-loop effective potential turns out to be gauge independent.
118533824
Free energy of Lorentz-violating QED at high temperature
In this paper we study the one- and two-loop contribution to the free energy in QED with Lorentz symmetry breaking introduced via constant CPT-even Lorentz-breaking parameters at the high temperature limit. We find the impact of the Lorentz-violating term for the free energy and carry out a numerical estimation for the Lorentz-breaking parameter.
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.
118455730
Effective potential for a SUSY Lee–Wick model: The Wess–Zumino case
Using a superfield generalization of the tadpole method, we study the one-loop effective potential for a Wess–Zumino model modified by a higher derivative term, inspired by the Lee–Wick model. The one-loop Kahlerian potential is also obtained by other methods and compared with the effective potential.
15427195
LIFETIMES OF HEAVY HADRONS
We review current status of theoretical predictions of lifetimes of heavy hadrons in heavy-quark expansion. We present a calculation of subleading 1/m_b corrections to spectator effects in the ratios of beauty hadron lifetimes. 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_b corrections brings into agreement the theoretical predictions and experimental observations of the ratio of lifetimes of Lambda_b-baryon and B_d meson. We obtain \tau(B_u)/\tau(B_d) = 1.09 \pm 0.03, \tau(B_s)/\tau(B_d)= 1.00 \pm 0.01, \tau(\Lambda_b)/\tau(B_d)= 0.87 \pm 0.05.
53398529
Hunting for CP violation with untagged charm decays
We construct a CP-violating observable which does not require flavor or CP tagging of the initial state. The proposed decay asymmetry could be measured at both threshold and non-threshold charm physics experiments and provide better sensitivity to small CP-violating parameters in charm decays.
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.
17373947
How to trap a non-standard penguin? Isospin symmetry violations in B-decays with enhanced chromomagnetic dipole operator
Abstract A recently proposed non-standard model solution to the problem of low semileptonic branching ratio B SL which suggests a large branching ratio for the decay b → sg is critically examined. It is shown that the effects of the enhanced chromomagnetic dipole operator might lead to significant violations of isospin symmetry in rate radiative decays of B -mesons.
118410106
Lifetime difference in Bs mixing: Standard Model and beyond
Abstract We present a calculation of 1 / m b 2 corrections to the lifetime differences of B s mesons Δ Γ B s in the heavy-quark expansion. We find that they are small to significantly affect Δ Γ B s and present the result for lifetime difference including non-perturbative 1 / m b and 1 / m b 2 corrections. We also analyze the generic Δ B = 1 New Physics contributions to Δ Γ B s and provide several examples.