相关论文: MeV gamma rays from Q-ball decay
Mirror matter models have been suggested recently as an explanation of neutrino puzzles and microlensing anomalies. We show that mirror supernovae can be a copious source of energetic gamma rays if one assumes that the quantum gravity scale…
The sudden release of copious $\g$-ray photons into a compact region creates an opaque photon--lepton fireball due to the prolific production of electron--positron pairs. The photons that we observe in the bursts emerge only at the end of…
We study the decay properties of a heavy-light meson. We reformulate the decay amplitudes for the heavy-light systems and find a new way to calculate decay rates. Applying this formulation, we find a new sum rule for the radiative decays of…
We have calculated the width of the rare decay $H\to\gamma\gamma Z$ at one-loop level in the standard model for Higgs boson masses in the range $115 {\rm GeV} \leq m_H \leq 160 {\rm GeV}$ . For this range of Higgs boson masses we find that…
Gamma-ray photons from young pulsars allow the deepest insight into the properties and interactions of high-energy particles with magnetic and photon fields in a pulsar magnetosphere. Measurements with the Compton Gamma-Ray Observatory have…
Partial decay widths of the heavy-light mesons, $D, D_s, B,$ and $B_s$, emitting one chiral particle ($\pi$ or $K$) are evaluated in the framework of a relativistic potential model. Decay amplitudes are calculated by keeping the Lorentz…
It is argued that the quark mass difference $m_b-m_c$ can be extracted with a high accuracy from experimental data on ratia of moments of lepton energy spectrum in semileptonic decays of $B$ mesons. Theoretical expressions for the moments…
In a Pulsar Wind Nebula (PWN), the lifetime of inverse Compton emitting electrons exceeds the lifetime of its progenitor pulsar, but it exceeds also the age of the electrons that emit via synchrotron radiation; i.e. while the PWN grows…
Excited Q-balls are studied by numerical simulations in the Minimal Supersymmetric Standard Model with supersymmetry broken by a gravity mediated mechanism. It is found that there is a suppression factor of $\cO(10^{-2})$ in the rate at…
The pion-bump structure in the gamma-ray spectrum is a direct proof for the hadronic origin of the gamma rays, and thus the decisive evidence for the acceleration of hadronic cosmic rays in astrophysical objects. However, the identification…
A theory is proposed to explain with simplicity the basic observed properties of a Gamma Ray Burst (GRB). It employs a well-known result of Schwinger, that static electric fields in excess of a critical value are unstable to pair creation,…
In a Pulsar Wind Nebula (PWN), the lifetime of inverse Compton emitting electrons exceeds the lifetime of its progenitor pulsar, but it exceeds also the age of the electrons that emit via synchrotron radiation; i.e. during the evolution of…
We study Q-ball formation in the expanding universe on 1D, 2D and 3D lattice simulations. We obtain detailed Q-ball charge distributions, and find that the distribution is peaked at Q^{3D}_{peak} \simeq 1.9\times 10^{-2} (|\Phi_{in}|/m)^2,…
The naturalness problem of PQ symmetry motivates study of the heavy QCD axion, with masses $m_a >$ 1 MeV generated at scales above the QCD scale, and low values of the PQ symmetry breaking scale, $f_a$. We compute the abundance of such…
We revisit the constraints implied by SN 1987 A observations on the decay rate of a multi-MeV $\nu_\tau$ decaying into the visible channel $\nu_\tau \rightarrow e^+ e^- \nu_e$, if its lifetime is more than 10 {\it sec.}. We discuss its…
Gamma ray lines are expected to be emitted as part of the afterglow of supernova explosions, because radioactive decay of freshly synthesised nuclei occurs. Significant radioactive gamma ray line emission is expected from 56Ni and 44Ti…
We calculate two- and three-body decays of the (lightest) vector glueball into (pseudo)scalar, (axial-)vector, as well as pseudovector and excited vector mesons\textbf{ }in the framework of a model of QCD. While absolute values of widths…
The invariant mass spectrum of the lepton pair in inclusive semileptonic $\bar B\to X_u \ell\bar\nu$ decay yields a model independent determination of $|V_{ub}|$. Unlike the lepton energy and hadronic invariant mass spectra, nonperturbative…
It is proposed that the gamma ray burst photons near the peak of the spectrum at several hundred KeV are produced on very compact scales, where photon production is limited by blackbody effects and/or the requirement of energetic quanta…
Glueballs remain an experimentally undiscovered prediction of QCD. Lattice QCD predicts a spectrum of glueballs, with the tensor $(J^{PC}=2^{++})$ glueball being the second lightest, behind the scalar glueball. From an effective hadronic…