27463348
Implications of new data in charmless B decays
Based on the latest experimental data of B ->pi pi and pi K modes, a model-independent analytical analysis is presented. The CP-averaged branching ratio difference Delta R=R-c-R-n in B ->pi K decays with R-c=2Br(pi K-0(-))/Br(pi(-)(K) over bar (0)) and R-n=Br(pi K-+(-))/2Br(pi(0)(K) over bar (0)) is reduced though it remains larger than the prediction from the standard model (SM) as both measured R-n and R-c are enhanced, which indicates that a room for new physics becomes smaller. The present data of pi pi decay reduce the ratio vertical bar C/T vertical bar from the previous value of vertical bar C/T vertical bar similar or equal to 0.8 to vertical bar C/T vertical bar similar or equal to 0.65, which is still larger than the theoretical estimations based on QCD factorization and pQCD. Within SM and flavor SU(3) symmetry, the current pi K data also diminish the ratio vertical bar C/T-'vertical bar from the previous value vertical bar C'/T'vertical bar similar or equal to 2 to vertical bar C'/T'vertical bar similar or equal to 1.16 with a large strong phase delta(C)'similar or equal to-2.65, while its value remains much larger than the one extracted from the pi pi modes. The direct CP violation A(CP)(pi(0)(K) over bar (0)) is predicted to be A(CP)(pi(0)(K) over bar (0))=-0.15 +/- 0.03, which is consistent with the present data. Two kinds of new effects in both strong and weak phases of the electroweak penguin diagram are considered. It is found that both cases can reduce the ratio to vertical bar C'/T'vertical bar=0.40 similar to 0.80 and lead to roughly the same predictions for CP violation in pi K-0(0).
119061151
Weak phase gamma and strong phase delta from CP averaged B ->pi pi and pi K decays
Assuming SU(3) symmetry for the strong phases in the four decay modes B-->pi(-)pi(+), pi(0)pi(+), pi(-)K(+), pi(-)(K) over bar(0) and ignoring the relative small electroweak penguin effects in those decays, the weak phase gamma and the strong phase delta can be determined in a model independent way by the CP averaged branching ratios of the four decay modes. It appears that the current experimental data for B-->pi pi and pi K decays prefer a negative value of cos gamma cos delta. By combining with the other constraints from V-ub B-d,s(0)-(B) over bar(d,s)(0) mixing, and the indirect CP-violating parameter epsilon(K) within the standard model, two favorable solutions for the phases gamma and delta are found to lie in the region 35 degrees less than or similar to gamma less than or similar to 62 degrees and 106 degrees less than or similar to delta less than or similar to 180 degrees or 86 degrees less than or similar to gamma less than or similar to 151 degrees and 0 degrees less than or similar to delta less than or similar to 75 degrees within 1 sigma standard deviation. It is noted that if allowing the standard deviation of the data to be more than 1 sigma, the two solutions could approach one solution with a much larger region for the phases gamma and delta. Direct CP asymmetry a(epsilon")((pi-K+)) in B -->pi(-)K(+) decay can be as large as the present experimental upper bound. Direct CP asymmetry a(epsilon")((pi+)pi-) in B-->pi(-)pi(+) decay can reach up to about 40% at the 1 sigma level.
18105043
Chiral couplings of W ′ and top quark polarization at the LHC
If a TeV-scale charged gauge boson (W') is discovered at the Large Hadron Collider (LHC), it will become imperative to determine its chiral couplings to standard model (SM) fermions in order to learn about the underlying theory containing the W'. We describe the reconstruction of the tb decay mode of the W' at the LHC, and identify various kinematic observables such as the angular distributions of the top quark and the lepton resulting from top decay that can be used to disentangle the chiral couplings of the W' to SM fermions. We demonstrate by presenting analytical expressions, numerical simulations, as well as intuitive illustrations for these observables at the LHC that among the SM fermions, the polarized top quark can most directly probe the chirality of such couplings.
123787607
The Contribution of Reggeon in charge exchange processes
We discuss in this paper The experimental results on maximum psedo-rapidity $\eta_{max}$ distribution in the charge exchange process $e+p\to e+n+X$ in ZEUS Collaboration at HERA. We calculate the contributions of \regg ($\rho$-Reggeon associated with $\rho$ meson) from regge phenomenology and $\pi^{+}$-exchange from pion cloud model. The results show that neither the \regg-exchange nor the pion cloud model alone can explain the experimental data well, but after considering both these two processes together, by using Monte Carlo simulation, a good agreement between theoretical results and experimental data is found. This means that in discussing the large rapidity gap phenomena in deep inelastic scattering, both of the two processes play substantial role.
118983113
Separating Different Models from Measuring $\alpha, \beta, \gamma$
New physics effects on the $B^0-\bar{B}^0$ mixing and B-decay amplitudes are discussed. By a combined analysis, the model of new physics can be partially distinguished.It is emphasized that the extraction of unitarity angles $\beta$ and $\gamma$ through rare decay $K\to \pi\nu\tilde{\nu}$ and charged B decay $B^{\pm}\to DK^{\pm}$ respectively is not likely to be affected by new physics. Such an observation could be used to distinguish the new physics effects from different mode ls. For instance, the top quark two-Higgs doublet model can be easily separated from those models without new phase in B-decay amplitudes, and can be further distinguished from the most general two Higgs doublet model by its absence of new phase in the $B^0-\bar{B}^0$ mixing.
119263633
Two Higgs bi-doublet left-right model with spontaneous P and CP violation
A left-right symmetric model with two Higgs bi-doublet is shown to be a consistent model for both spontaneous P and CP violation. The flavor changing neutral currents can be suppressed by the mechanism of approximate global U(1) family symmetry. The constraints from neural K meson mass difference ΔmK are calculated and it is demonstrated that a right-handed gauge boson W2 contribution in box-diagrams with mass well below 1 TeV is allowed due to a cancelation caused by a light-charged Higgs boson with a mass range of 150–300 GeV. The W2 contribution to εK can be suppressed from an appropriate choice of additional CP phases appearing in the right-handed Cabbibo-Kobayashi-Maskawa matrix. The model is also found to be fully consistent with B0 mass difference ΔmB and the mixing induced CP violation sin2βJ/ Ψ, which is usually difficult for the model with only one Higgs bi-doublet. The new physics beyond the standard model can be directly searched at the colliders LHC and ILC.
118540037
Self-energy of strongly interacting fermions in medium: A holographic approach
Abstract We consider the self-energy of strongly interacting fermions in the medium using gauge/gravity duality of D 4 / D 8 system. We study the mass generation of the thermal and/or dense medium and the collective excitation called plasmino, by considering the spectral function of fermion and its dispersion relation. Our results are very different from those of the hard thermal loop method: for zero density, there is no thermal mass or plasmino in any phase. Plasmino in the deconfined phase is not allowed in D 4 / D 8 setup. In the confined phase, there is a plasmino mode only for a window of density.
119257921
Geometry of the effective Majorana neutrino mass in the $0\nu\beta\beta$ decay
The neutrinoless double-beta (0 nu beta beta) decay is a unique process used to identify the Majorana nature of massive neutrinos, and its rate depends on the size of the effective Majorana neutrino mass (ee). We put forward a novel 'coupling-rod' diagram to describe (ee) in the complex plane, by which the effects of the neutrino mass ordering and CP-violating phases on (ee) are intuitively understood. We show that this geometric language allows us to easily obtain the maximum and minimum of vertical bar (ee)vertical bar. It remains usable even if there is a kind of new physics contributing to (ee), and it can also be extended to describe the effective Majorana masses (e mu), (e tau), (mu mu), (mu tau), and (tau tau) which may appear in some other lepton-number violating processes.
119273408
Majorana CP-violating phases in neutrino-antineutrino oscillations and other lepton-number-violating processes
If the massive neutrinos are identified to be the Majorana particles via a convincing measurement of the neutrinoless double beta (0 nu beta beta) decay, how to determine the Majorana CP-violating phases in the 3 x 3 lepton flavor mixing matrix U will become a desirable experimental question. The answer to this question is to explore all the possible lepton-number-violating (LNV) processes in which the Majorana phases really matter. In this paper we carry out a systematic study of CP violation in neutrino-antineutrino oscillations, whose CP-conserving parts involve six independent 0 nu beta beta-like mass terms (alpha beta) and CP-violating parts are associated with nine independent Jarlskog-like parameters V-alpha beta(ij) (for alpha, beta = e, mu, tau and i, j = 1, 2, 3). With the help of current neutrino oscillation data, we analyze the sensitivities of vertical bar (alpha beta)vertical bar and V-alpha beta(ij) to the three CP-violating phases of U, and illustrate the salient features of six independent CP-violating asymmetries between nu(alpha) -> (nu) over bar (beta) and (nu) over bar (alpha) -> nu(beta) oscillations. As a by-product, the effects of the CP-violating phases on the LNV decays of doubly and singly charged Higgs bosons are reexamined by taking account of the unsuppressed value of theta(13). Such CP-conserving LNV processes can be complementary to the possible measurements of neutrino-antineutrino oscillations in the distant future.
771773
High spin baryon in hot strongly coupled plasma
We consider a strings-junction holographic model of a probe baryon in the finite-temperature supersymmetric Yang-Mills dual of the AdS-Schwarzschild black hole background. In particular, we investigate the screening length for a high spin baryon composed of rotating N-c heavy quarks. To rotate quarks by finite force, we put a hard infrared cutoff in the bulk and give quarks a finite mass. We find that N-c microscopic strings are embedded reasonably in the bulk geometry when they have finite angular velocity omega, similar to the meson case. By defining the screening length as the critical separation of quarks, we compute the omega dependence of the baryon screening length numerically and obtain a reasonable result which shows that baryons with high spin dissociate more easily. Finally, we discuss the relation between J and E-2 for baryons.
14308322
HOLOGRAPHIC SUPERCONDUCTOR FOR A LIFSHITZ FIXED POINT
We consider the gravity dual of strongly coupled system at a Lifshitz-fixed point and finite temperature, which was constructed in a recent work arXiv:0909.0263. We construct an Abelian-Higgs model in that background and calculate condensation and conductivity using holographic techniques. We find that condensation happens and DC conductivity blows up when temperature turns below a critical value. We also study the zero temperature limit of strongly coupled system at the Lifshitz-fixed point.