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.
117901603
X(3872) 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) and study its properties.
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)
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.
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
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.
118542970
Ambiguities of the C P T -even aether-like Lorentz-breaking term at finite temperature
In this paper, we consider the finite-temperature behavior of the $CPT$-even aether-like Lorentz-breaking term in the extended Lorentz-breaking QED and demonstrate that its ambiguities, whose presence has been shown earlier in the zero-temperature case, stay also at a finite temperature.
119226354
On the one-loop effective potential in the higher-derivative four-dimensional chiral superfield theory with a nonconventional kinetic term
Abstract We explicitly calculate the one-loop effective potential for a higher-derivative four-dimensional chiral superfield theory with a nonconventional kinetic term. We consider the cases of minimal and nonminimal general Lagrangians. In particular, we find that in the minimal case the divergent part of the one-loop effective potential vanishes by reason of the chirality.
125450100
A Coherent State Formulation for the Relativistic Field Theories
119201043
Kaluza-Klein description of geometric phases in graphene
In this paper, we use the Kaluza-Klein approach to describe topological defects in a graphene layer. Using this approach, we propose a geometric model allowing to discuss the quantum flux in K-spin subspace. Within this model, the graphene layer with a topological defect is described by a four-dimensional metric, where the deformation produced by the topological defect is introduced via the three-dimensional part of metric tensor, while an Abelian gauge field is introduced via an extra dimension. We use this new geometric model to discuss the arising of topological quantum phases in a graphene layer with a topological defect.
119188251
On the duality in four-dimensional Lorentz-breaking field theories
We consider new issues of duality in four-dimensional Lorentz-breaking field theories. In particular, we demonstrate that the arising of the aether-like Lorentz-breaking term is necessary in order for the 4D models to display the duality analog between the MCS and self-dual models in 3D. We further study the dispersion relations in both theories and discuss the physical contents of the models involved in this new duality.