14564633
CHARM MIXING IN THE STANDARD MODEL AND BEYOND
Quantum mechanical meson-antimeson oscillations are sensitive to heavy degrees of freedom which propagate in the underlying mixing amplitudes. Comparing observed meson mixing with predictions of the Standard Model (SM), modern experimental studies would be able to constrain models of New Physics (NP). Yet, extensive precission data from B-factories and the Tevatron collider show that the large SM mixing succesfully describes all available experimental data in Bd and Bs oscillations. The only flavor oscillation not yet observed is that of the charmed meson D, where SM mixing is very small and the NP component can stand out. This situation is an exact opposite to what happens in the B system, where B − B0 mixing measurements are used to constrain top quark couplings. Together with the one loop Standard Model effects NP effects can contribute to ∆C = 1 (decays) or ∆C = 2 (mixing) transitions. In the case of D −D0 mixing these operators generate contributions to the effective operators that change D state into D0 state, leading to the mass eigenstates |D1,2〉 = p|D〉 ± q|D〉, (1)
35942201
Is B-->Xs gamma equal to b-->s gamma ? Spectator contributions to rare inclusive B decays.
In $B \to X_s \gamma $ there are perturbative $QCD$ corrections at order $\alpha_s$ not only to the single quark line process $ b \to s \gamma$ but also coming from a set of diagrams where the weak interaction vertex involves a gluon which interacts with the spectator quark in the B hadron. We discuss the impact of the full set of these diagrams. These can influence the decay rate and also the line shape of the photon spectrum as they favor a softer photon energy than does the pure spectator decay $b \to s \gamma$. A subset of these diagrams generate differences in the decay rates for charged and neutral B's , $B^+ \to X_s \gamma$ vs. $B^0 \to X_s \gamma$ which can be searched for experimentally, although our calculation indicates that the effect will be hard to observe. Bound state effects turn out to be required to give rise to spectator corrections to the decay rate at order $\alpha_s$. The resulting contribution to the total rate is rather small (of about $5 \% $ ), although the effect is somewhat larger on portions of the photon spectrum.
8094700
Charm Phenomenology for CKM Parameters
We review several key aspects of charm phenomenology which are important for the general program of determination of matrix elements of the Cabbibo-Kobayashi-Maskava (CKM) matrix. We argue that charm physics plays an important role in reducing uncertainties in non-perturbative QCD parameters whose values are required for understanding of underlying quark-level processes. We also review the current status of searches for new physics in mixing and CP violation in charmed mesons both at the currently operating and proposed facilities.
118687281
Hadronic D and D(s) Meson Decays
We provide a comprehensive review of hadronic decays of D and D_s mesons. We discuss current theoretical and experimental challenges and successes in understanding of hadronic transitions of those mesons. A brief overview of the theoretical and experimental tools are given before discussing the absolute branching fractions for D and D_s mesons. Cabibbo suppressed and rare hadronic decays are discussed and compared with theory before discussing our understanding of hadronic multibody decays.
14759150
Heavy meson molecules in effective field theory
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 D0 mesons for the existence of bound states in the D0D0 and D�0D �0
17946700
CP-violation in charm
I review recent results in theoretical and experimental analyses of CP-violation in charmed transitions, paying particular attention to constraints on parameters of beyond the Standard Model interactions.
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.
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.
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.
119230860
On the aether-like Lorentz-breaking actions
We demonstrate the generation of the CPT-even, aether-like Lorentz-breaking actions for the scalar and electromagnetic fields via their appropriate Lorentz-breaking coupling to spinor fields in three, four and five space-time dimensions. Besides, we show that the aether-like terms for the spinor field also can be generated as a consequence of the same couplings. Also we discuss the dispersion relations in the theories with aether-like Lorentz-breaking terms and find the tree-level effective (Breit) potential for fermion scattering and the one-loop effective potential corresponding to the action of the scalar field.
119181109
Generation of axionlike couplings via quantum corrections in a Lorentz-violating background
Light pseudoscalars, or axion like particles (ALPs), are much studied due to their potential relevance to the fields of particle physics, astrophysics and cosmology. The most relevant coupling of ALPs from the viewpoint of current experimental searches is to the photon: in this work, we study the generation of this coupling as an effect of quantum corrections, originated from an underlying Lorentz violating background. Most interestingly, we show that the interaction so generated turns out to be Lorentz invariant, thus mimicking the standard ALPs coupling to the photon that is considered in the experiments. This consideration implies that violations of spacetime symmetries, much studied as possible consequences of physics in very high energy scales, might infiltrate in other realms of physics in unsuspected ways. Additionally, we conjecture that a similar mechanism can also generate Lorentz invariant couplings involving scalar particles and photons, playing a possible role in the phenomenology of Higgs bosons.