115948369
Phenomenology of the Neutral Higgs-Boson in the Weinberg-Salam Theory of the Weak Interactions.
10063732
Effective Lagrangian approach to weak radiative decays of heavy hadrons.
Motivated by the observation of the decay B\ifmmode\bar\else\textasciimacron\fi{}\ensuremath{\rightarrow}K${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}^{\mathrm{*}}$\ensuremath{\gamma} by the CLEO Collaboration, we have systematically analyzed the two-body weak radiative decays of bottom and charmed hadrons. There exist two types of weak radiative decays: One proceeds through the short-distance b\ensuremath{\rightarrow}s\ensuremath{\gamma} transition and the other occurs through W exchange accompanied by a photon emission. Effective Lagrangians are derived for the W-exchange bremsstrahlung processes at the quark level and then applied to various weak electromagnetic decays of heavy hadrons. Predictions for the branching ratios of B${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}^{0}$\ensuremath{\rightarrow}${\mathit{D}}^{\mathrm{*}0}$\ensuremath{\gamma}, ${\mathrm{\ensuremath{\Lambda}}}_{\mathit{b}}^{0}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\Sigma}}}_{\mathit{c}}^{0}$\ensuremath{\gamma}, ${\mathrm{\ensuremath{\Xi}}}_{\mathit{b}}^{0}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\Xi}}}_{\mathit{c}}^{0}$\ensuremath{\gamma}, and ${\mathrm{\ensuremath{\Xi}}}_{\mathit{b}}^{0}$\ensuremath{\rightarrow}\ensuremath{\Xi}${\mathcal{'}}_{\mathit{b}}^{0}$\ensuremath{\gamma} are given. In particular, we find scrB(B${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}^{0}$\ensuremath{\rightarrow}${\mathit{D}}^{\mathrm{*}0}$\ensuremath{\gamma})\ensuremath{\approxeq}0.9\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}6}$. Order of magnitude estimates for the weak radiative decays of charmed hadrons, ${\mathit{D}}^{0}$\ensuremath{\rightarrow}K${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}^{\mathrm{*}0}$\ensuremath{\gamma}, ${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\Sigma}}}^{+}$\ensuremath{\gamma}, and ${\mathrm{\ensuremath{\Xi}}}_{\mathit{c}}^{0}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\Xi}}}^{0}$\ensuremath{\gamma}, are also presented. Within this approach, the decay asymmetry for antitriplet to antitriplet heavy baryon weak radiative transitions is uniquely predicted by heavy quark symmetry. The electromagnetic penguin contribution to ${\mathrm{\ensuremath{\Lambda}}}_{\mathit{b}}^{0}$\ensuremath{\rightarrow}\ensuremath{\Lambda}\ensuremath{\gamma} is estimated by two different methods and its branching ratio is found to be of the order of 1\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}5}$. We conclude that weak radiative decays of bottom hadrons are dominated by the short-distance b\ensuremath{\rightarrow}s\ensuremath{\gamma} mechanism.
13594754
Heavy-flavor-conserving nonleptonic weak decays of heavy baryons.
The heavy-flavor-conserving nonleptonic weak decays of heavy baryons are studied in a formalism that incorporates both heavy-quark symmetry and chiral symmetry. The phenomenological {Delta}{ital S}=1 nonleptonic weak chiral Lagrangian for these transitions contains two independent coupling constants that describe the transitions between two flavor-SU(3) antitriplet heavy baryons, and the transitions between two flavor-SU(3) sextet heavy baryons. In the MIT bag model and the diquark model, only transitions between antitriplets are allowed. The coupling constants for these transitions are calculated in both models. The result is applied to specific nonleptonic decays such as {Xi}{sub {ital c}}{r arrow}{Lambda}{sub {ital c}}{pi}, and the branching ratios are found to be of the order of 10{sup {minus}4}. An example of a nonleptonic decay due to symmetry breaking is provided by {Omega}{sub {ital c}}{r arrow}{Xi}{sub {ital c}}{sup {prime}}{pi}, which is estimated to have a smaller branching ratio, of the order of 10{sup {minus}5}.
36067168
Dimensional regularization and perturbative solution of the chiral Schwinger model.
The anomalous chiral Schwinger model is regulated by the method of dimensional regularization and is solved by diagrammatic perturbative expansion. It is shown that there is a regulation ambiguity in the solution. The result disagrees with Das's assertion and agrees with that of Jackiw, Rajaraman, and others.
34810684
Restudy of the open-superstring tree amplitudes by looking at their field-theoretical limits.
We carry out complete computations of some open- and closed-superstring tree amplitudes by using the bosonized covariant vertices. Some open-superstring amplitudes so obtained are shown to be different from those obtained in the light-cone gauge approach by some numerical factors. The low-energy limits of our five open-superstring amplitudes are then shown to match the five super Yang-Mills field amplitudes while the five light-cone gauge open-superstring amplitudes fail to do so.
120093276
CONSISTENT FACTORIZATION AND TWIST-3 CONTRIBUTIONS TO THE POLARIZED NUCLEON STRUCTURE FUNCTION g2(x,Q2)
Quark mass effects are clarified in the parton model approach to the transversely polarized nucleon structure function. The special propagator technique is employed to obtain manifestly gauge invariant results and extract the buried short-distance contributions inside the soft part after momentum factorization in the collinear expansion approach. A generalized massive special propagator for a massive quark is constructed. We identify the corresponding matrix elements of the transversely polarized structure function in deep inelastic scattering by the massive special propagator technique.
119119504
Constraints on Light Majorana dark Matter from Colliders
Abstract We explore model-independent collider constraints on light Majorana dark matter particles. We find that colliders provide a complementary probe of WIMPs to direct detection, and give the strongest current constraints on light DM particles. Collider experiments can access interactions not probed by direct detection searches, and outperform direct detection experiments by about an order of magnitude for certain operators in a large part of parameter space. For operators which are suppressed at low momentum transfer, collider searches have already placed constraints on such operators limiting their use as an explanation for DAMA.
119095935
Brownian motion of a charged test particle in vacuum between two conducting plates
The Brownian motion of a charged test particle caused by quantum electromagnetic vacuum fluctuations between two perfectly conducting plates is examined and the mean squared fluctuations in the velocity and position of the test particle are calculated. Our results show that the Brownian motion in the direction normal to the plates is reinforced in comparison to that in the single plate case. The effective temperature associated with this normal Brownian motion could be three times as large as that in the single plate case. However, the negative dispersions for the velocity and position in the longitudinal directions, which could be interpreted as reducing the quantum uncertainties of the particle, acquire positive corrections due to the presence of the second plate, and are thus weakened.
122365177
Euclidean action, partition function and thermodynamics of a black-hole global-monopole system
A spherical black-hole global-monopole system in thermal equilibrium is examined from the perspective of a grand canonical ensemble in which the temperature and surface area are fixed at a finite boundary. Using the Euclidean action with constraints eliminated, we investigate the thermodynamics of the system. It is shown that there exists a stable thermal equilibrium for the system in the ensemble. A comparison with ordinary black holes under equivalent boundary conditions indicates that if such a system exists, it will not decay spontaneously to a black hole without a global monopole.
119408784
Meson spectrum in Regge phenomenology
Abstract.Under the assumption that both light and heavy quarkonia populate approximately linear Regge trajectories with the requirements of additivity of intercepts and inverse slopes, the masses of different meson multiplets are estimated. The predictions derived from the quasi-linear Regge trajectories are in reasonable agreement with those given by many other references.
119828482
ON THE PROBLEM OF THE ISODOUBLET OF THE 2 3S1 MESON NONET
Employing three different and complementary approaches, chiral equal-splitting laws, Regge phenomenology and meson–meson mixing, we show that the mass of the isodoublet of the 2 3S1 meson nonet is in the range in 1530–1580 MeV.