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Y. N. Srivastava

Publications and source records attributed to Y. N. Srivastava.

At least 127 records · Page 7Linked to original sources
arXiv2000

Gravitational Decay Modes of the Standard Model Higgs Particle

If the Einstein field equations are employed at the tree level, then the decay of the standard model Higgs particle into two gravitons is shown to be independent of the gravitational coupling strength G. The result follows from the physical equivalence between the Higgs induced ``inertial mass'' and the ``gravitational mass'' of general relativity. If the Higgs mass lies well between the mass of a bottom quark anti-quark pair and the mass of a top quark anti-quark pair, then the Higgs decay into two gravitons will dominate both the QED induced two photon decay and the QCD induced two jet decays.

hep-ph↗
arXiv2000

Breakdown of the KLN Theorem for Charged Particles in Condensed Matter

The Kinoshita-Lee-Nauenberg (KLN) theorem describes the fact that inclusive electromagnetic and weak production processes in the vacuum do not contain singularities in the ultra-relativistic limit of zero mass. When these production processes occur in condensed matter, the KLN theorem fails. One consequence of this failure is that precision lifetime determinations of stopped muons will depend on the nature of the surrounding material.

hep-ph↗
arXiv1999

Entropy Production and Cosmological Inflation

The notion of inflation (past or present) in standard cosmological models is shown to be a consequence of a sufficiently high second law entropy production from the internal heating of the universal expansion. The longitudinal viscous internal heating of matter requires neither ``inflaton'' fields nor ``quintessence'' fields which in theory may induce a cosmological term into the Einstein equations. The purely thermodynamic principles required to understand inflation within the context of the standard general relativity equations will be discussed in detail.

gr-qc↗
arXiv1999

Hadronic Total Cross-sections Through Soft Gluon Summation in Impact Parameter Space

The Bloch-Nordsieck model for the parton distribution of hadrons in impact parameter space, constructed using soft gluon summation, is investigated in detail. Its dependence upon the infrared structure of the strong coupling constant $α_s$ is discussed, both for finite as well as singular, but integrable, $α_s$. The formalism is applied to the prediction of total proton-proton and proton-antiproton cross-sections, where screening, due to soft gluon emission from the initial valence quarks, becomes evident.

hep-ph↗
arXiv1999

Production of Like Sign Di-Leptons in p-p Collisions Through Composite Majorana Neutrinos

The production of Like-Sign-Di-leptons (LSD), in the high energy lepton number violating ($ΔL = +2$) reaction, p p --> 2jets + l+l+ (l=e,μ,τ) of interest for the experiments to be performed at the forthcoming Large Hadron Collider (LHC), is investigated in detail, taking up a composite model scenario in which the exchanged virtual composite neutrino is assumed to be a Majorana particle that couples to the light leptons via the $SU(2)\times U(1)$ gauge bosons through a magnetic type coupling ($σ_{μν}$). An helicity projection method is used to evaluate exactly the tree-level amplitudes of the contributing parton subprocesses ($2\to 4$), which allows to take into account all exchange diagrams and occurring interferences. Numerical estimates of the corresponding signal cross-section that implement kinematical cuts needed to suppress the Standard Model background, are presented which show that in some regions of the parameter space the total number of LSD events is well above the background. Assuming non-observation of the LSD signal it is found that LHC would exclude a composite Majorana neutrino up to 850 GeV (if one requires 10 events for discovery). The sensitivity of LHC experiments to the parameter space is then compared to that of the next generation of neutrinoless double beta decay ($ββ_{0ν}$) experiment, GENIUS, and it is shown that they will provide constraints of the same order of magnitude and will play a complementary role.

hep-ph↗
arXiv1999

Photon Polarization Measurements without the Quantum Zeno Effect

We consider a photon beam incident on a stack of polarizers as an example of a von Neumann projective measurement, theoretically leading to the quantum Zeno effect. The Maxwell theory (which is equivalent to the single photon Schrödinger equation) describes measured polarization phenomena, but without recourse to the notion of a projective measurement.

quant-ph↗
arXiv1998

Electron Neutrino Sources from the Core of the Earth

The physical interpretation of extensive measurements of electron neutrinos (in laboratories located on or somewhat below the Earth's surface) often require geophysical notions concerning the possible neutrino sources. Here, we discuss the notion that the Earth's core is a substantial source of low energy electron neutrinos.

hep-ph↗
arXiv1998

Quantum Measurements, Information and Entropy Production

In order to understand the Landau-Lifshitz conjecture on the relationship between quantum measurements and the thermodynamic second law, we discuss the notion of ``diabatic'' and ``adiabatic'' forces exerted by the quantum object on the classical measurement apparatus. The notion of heat and work in measurements is made manifest in this approach, and the relationship between information entropy and thermodynamic entropy is explored.

quant-ph↗
arXiv1998

Real Time Radiative Corrections to Charged Particle Decay Laws

The real time exponential decay laws for meta-stable charged particles are shown to require radiative corrections. The methods employed are well known to be valid for radiatively correcting Breit-Wigner line shapes. Radiative corrections contribute substantially to precision life time measurements of muons and pions when initially stopped in condensed matter.

hep-ph↗
arXiv1998

Neutrino Mass Difference Induced Oscillations in Observed Muon Decays

The recent real time KARMEN anomaly for the electron neutrino counting rates (obtained from stopped muon decays) is analyzed by employing a neutrino flavor rotation model in which the muon neutrino is in a superposition of only two mass eigenstates. On the basis of experimental electron neutrino counting oscillations, we find a neutrino mass splitting $|m_2^2-m_1^2|=(0.22\pm 0.02)(eV/c^2)^2$ and a flavor rotation angle $ϕ=0.34\pm 0.10$, both within a 95% confidence interval.

hep-ph↗
arXiv1998

The Dynamical and Static Casimir Effects and the Thermodynamic Instability

The dynamical Casimir effect for the ideal case of two perfectly conducting non-charged parallel plates, is discussed using the zero-point energy summation method to the first order in perturbation theory. We show that it is possible to create photon radiation when the two plates are modulated rapidly in time. Moreover we point out that the static Casimir energy between two conducting non-charged parallel plates violates the thermodynamic stability condition normally associated with the second law of thermodynamics.

hep-ph↗
arXiv1998

The Casimir Effect and Thermodynamic Instability

One loop field theory calculations of free energies quite often yield violations of the stability conditions associated with the thermodynamic second law. Perhaps the best known example involves the equation of state of black holes. Here, it is pointed out that the Casimir force between two parallel conducting plates also violates a thermodynamic stability condition normally associated with the second law of thermodynamics.

quant-ph↗
arXiv1998

Acuasal Behavior in Quantum Electrodynamics

Acausal features of quantum electrodynamic processes are discussed. While these processes are not present for the classical electrodynamic theory, in the quantum electrodynamic theory, acausal processes are well known to exist. For example, any Feynman diagram with a ``loop'' in space-time describes a ``particle'' which may move forward in time or backward in time or in space-like directions. The engineering problems involved in experimentally testing such causality violations on a macroscopic scale are explored.

quant-ph↗
arXiv1997

Neutrinoless Double Beta Decay with Composite Neutrinos

We study in detail the contribution of heavy composite Majorana neutrinos to neutrino-less double beta decay. Our analysis confirms the result of a previous estimate by two of the authors. Excited neutrinos couple to the electroweak gauge bosons through a magnetic type effective Lagrangian. The relevant nuclear matrix element is related to matrix elements available in the literature and current bounds on the half-life of neutrino-less double beta decay are converted into bounds on the compositeness scale and/or the heavy neutrino mass. Our bounds are of the same order of magnitude as those available from accelerator experiments.

hep-ph↗
arXiv1997

Thermodynamic Equations of State for Dirac and Majorana Fermions

The thermodynamic equations of state for Majorana and Dirac fermions are quite different even in the limit of zero mass. The corresponding equations are derived from general principles, and then applied to neutrinos. The nature of the approach to equilibrium is explored, along with the subtleties of low or zero mass neutrinos interacting via purely left-handed currents. Possible applications to cosmology, supernovae, and supersymmetry are discussed.

hep-ph↗
arXiv1997

Phase Coherence in Quantum Brownian Motion

The quantum theory of Brownian motion is discussed in the Schwinger version wherein the notion of a coordinate moving forward in time $x(t)$ is replaced by two coordinates, $x_+(t)$ moving forward in time and $x_-(t)$ moving backward in time. The role of the doubling of the degrees of freedom is illustrated for the case of electron beam two slit diffraction experiments. Interference is computed with and without dissipation (described by a thermal bath). The notion of a dissipative interference phase, closely analogous to the Aharonov-Bohm magnetic field induced phase, is explored.

quant-ph↗
arXiv1997

Of Course Muons Can Oscillate

Recent theoretical claims not withstanding, muons can and do oscillate. Muons produced in association with neutrinos (if masses and mixing angles are nonzero) exhibit a joint oscillating spatial distribution. The possible use of muon oscillations as a probe of neutrino mass and mixing parameters is discussed using very simple physical arguments. Space-time oscillations in the secondary decay vertices of muons (produced by pion decay) persist after summing over all undetected neutrinos.

hep-ph↗