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.
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.
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.
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.
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.
118499576
Induction of the higher-derivative Chern-Simons extension in QED$_3$
We perform the perturbative generation of the higher-derivative Chern-Simons contribution to the effective action in the three-dimensional QED at zero and finite temperature. In the latter case, we show that as the temperature goes to infinity this contribution vanishes. However, as expected, as the temperature goes to zero only the covariant part survives. The non-covariant part contributes only in intermediate temperatures where presents a maximum.
118691409
Gödel-type universes and chronology protection in Hořava–Lifshitz gravity
Abstract In the attempts toward a quantum gravity theory, general relativity faces a serious difficulty since it is non-renormalizable theory. Hořava–Lifshitz gravity offers a framework to circumvent this difficulty, by sacrificing the local Lorentz invariance at ultra-high energy scales in exchange of power-counting renormalizability. The Lorentz symmetry is expected to be recovered at low and medium energy scales. If gravitation is to be described by a Hořava–Lifshitz gravity theory there are a number of issues that ought to be reexamined in its context, including the question as to whether this gravity incorporates a chronology protection, or particularly if it allows Godel-type solutions with violation of causality. We show that Hořava–Lifshitz gravity only allows hyperbolic Godel-type space-times whose essential parameters m and ω are in the chronology respecting intervals, excluding therefore any noncausal Godel-type space-times in the hyperbolic class. There emerges from our results that the famous noncausal Godel model is not allowed in Hořava–Lifshitz gravity. The question as to whether this quantum gravity theory permits hyperbolic Godel-type solutions in the chronology preserving interval of the essential parameters is also examined. We show that Hořava–Lifshitz gravity not only excludes the noncausal Godel universe, but also rules out any hyperbolic Godel-type solutions for physically well-motivated perfect-fluid matter content.
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.
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.
117655072
On the higher-derivative Lorentz-breaking terms
The first one-loop higher-derivative contribution to the effective action of the Lorentz-breaking spinor QED is obtained and shown to be finite and ambiguous.