119285658
Braneworld solutions for F(R) models with non-constant curvature
Abstract This work deals with braneworld scenarios with generalized gravity. We investigate models where the potential of the scalar field is polynomial or nonpolynomial. We obtain exact and approximated solutions for the scalar field, warp factor and energy density, in the complex scenario with no restriction on the scalar curvature. In particular, we describe the case where the brane may split, engendering internal structure, with the splitting caused by the same parameter that controls deviation from standard gravity.
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.
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.
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.
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.
14121745
Lifetime differences in heavy mesons with time independent measurements
Heavy meson pairs produced in the decays of heavy quarkonium resonances at ${e}^{+}{e}^{\ensuremath{-}}$ machines (beauty and tau-charm factories) have the useful property that the two mesons are in the $CP$-correlated states. We show that this leads to time-independent correlations allowing the extraction of the lifetime difference $\ensuremath{\Delta}{\ensuremath{\Gamma}}_{D}$ and other mixing parameters. In particular, for the decay $\ensuremath{\psi}(3770)\ensuremath{\rightarrow}{D}^{0}{\overline{D}}^{0}$ the correlation of a flavor specific decay of one $D$ with a $CP$-specific decay of the other $D$ is linearly sensitive to the ${D}^{0}$ lifetime difference. The utility of this method is considered at CLEO-c as well as future threshold charm factories. We include the impact of possible $CP$-violating effects and present the complete results for time-integrated $CP$-entangled decay rates with $CP$ violation taken into account. We comment on the utility of using this method to extract the lifetime difference of neutral $B$ mesons at future high luminosity $B$ factories.
117653354
Searching for New Physics with Charm
I provide a comprehensive review of indirect searches for New Physics with charmed mesons. I discuss current theoretical and experimental challenges and successes in understanding decays and mixings of those mesons. I argue that in many New Physics scenarios strong constraints, that surpass those from other search techniques, could be placed on the allowed model parameter space using the existent data from studies of charm transitions. This has direct implications for direct searches of physics beyond the Standard Model at the LHC.
119494597
X(3872): Hadronic molecules in effective field theory
Abstract We consider the implications from the possibility that the recently observed state X ( 3872 ) is a meson–antimeson molecule. We write an effective Lagrangian consistent with the heavy-quark and chiral symmetries needed to describe X ( 3872 ) . We explore the consequences of the assumption that X ( 3872 ) is a molecular bound state of D ∗ 0 and D ¯ 0 mesons for the existence of bound states in the D 0 D ¯ 0 and D ∗ 0 D ¯ ∗ 0 channels.
118893294
CP-VIOLATION AND MIXING IN CHARMED MESONS
The Standard Model contribution to D0 D 0 mixing is dominated by the contributions of light s and d quarks. Neglecting the tiny effects due to b quark, both mass and lifetime differences vanish in the limit of SU(3)F symmetry. Thus, the main challenge in the Standard Model calculation of the mass and width difference in the D0 D 0 system is to estimate the size of SU(3) breaking effects. We prove that D meson mixing occurs in the Standard Model only at second order in SU(3) violation. We consider the possibility that phase space effects may be the dominant source of SU(3) breaking. We find that y = (�) /(2) of the order of one percent is natural in the Standard Model, potentially reducing the sensitivity to new physics of measurements of D meson mixing. We also discuss the possibility of observing lifetime differences and CP violation in charmed mesons both at the currently operating and proposed facilities.