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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 721 records · Page 40
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

New solutions to the Dirac equation for particles in a magnetic field and a medium

We briefly review the application of the method of exact solutions of quantum equations for the description of charged particle motion in external fields. We develop a quantization technique by using the lowering and raising operators to describe the states of fermions moving in a magnetic field and a dense medium. For the first time we have posed and solved the problem of a charged fermion moving in a medium and an external magnetic field by taking into account the anomalous magnetic moment of the particle: we have obtained exact solutions for the wave functions and energy spectrum of the corresponding modified Dirac equation. We discuss a quasi-classic interpretation of the solutions obtained and, in particular, find a correction for the synchrotron radiation intensity dependent on medium density.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Proposal to Search for Magnetically Charged Particles with Magnetic Charge 1e

A model for composite elementary Standard Model (SM) particles based upon magnetically bound vorton pairs, we briefly introduce here, predicts the existence of a complete family of magnetically charged particles, as well as their neutral isotopic partners (all counterparts to the SM elementary particles), in which the lowest mass (charged) particle would be an electrically neutral stable lepton, but which carries a magnetic charge equivalent to 1e. This new particle, which we call a magneticon (a counterpart to the electron) would be pair produced at all e + e - colliders at an E cm above twice its mass. In addition, PP and PPbar colliders should also be able to produce these new particles through the Drell-Yan process. To our knowledge, no monopole search experiment has been sensitive to such a low-charged magnetic monopole above a particle mass of about 5 GeV/c 2 . Hence, we propose that a search for such a stable particle of magnetic charge 1e should be undertaken. We have taken the ATLAS detector at the LHC as an example in which this search might be done. To this end, we modeled the magnetic fields and muon trigger chambers of this detector. We show results from a simple Monte Carlo simulation program to indicate how these particles might look in the detector and describe how one might search for these new particles in the ATLAS data stream.

ATLAS↗
DOE OSTI2017

Classical integrable many-body systems disconnected with semi-simple Lie algebras

The review of the results in the theory of integrable many-body systems disconnected with semisimple Lie algebras is done. The one-dimensional systems of light Calogero-Sutherland-Moser particles interacting with one particle of infinite mass located at the origin are described in detail. In some cases the exact solutions of the equations of motion are obtained. The general theory of integration of the equations of motion needs the methods of algebraic geometry. The Lax pairs with spectral parameter are constructed for this purpose. The theory still contains many unsolved problems.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Dirac particle in Riemann-Cartan spacetimes

Dynamics of a Dirac particle in general Riemann-Cartan spacetimes is considered. The Hermitian Dirac Hamiltonian is derived and is transformed to the Foldy-Wouthuysen representation for an arbitrary spacetime geometry. The contribution of the torsion field to the Foldy-Wouthuysen Hamiltonian is found. The new bounds on Cartan’s spacetime torsion are obtained.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Identity method for particle number fluctuations and correlations

An incomplete particle identification distorts the observed event-by-event fluctuations of the hadron chemical composition in nucleus-nucleus collisions. A new experimental technique called the identity method was recently proposed. It eliminated the misidentification problem for one specific combination of the second moments in a system of two hadron species. In the present paper, this method is extended to calculate all the second moments in a system with an arbitrary number of hadron species. Special linear combinations of the second moments are introduced. These combinations are presented in terms of single-particle variables and can be found experimentally from the event-by-event averaging. The mathematical problem is then reduced to solving a system of linear equations. The effect of incomplete particle identification is fully eliminated from the final results.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Investigation of Single and Pair Production of J/ψ Particles in the D0 Experiment at the Tevatron Accelerator

In this paper, the results of investigation of single and pair production of J/ψ mesons in the D0 experiment at the Tevatron accelerator are considered. The contributions of single and double parton interactions to the total cross section of the pair production of J/ψ mesons are estimated for the first time. With the help of these measurements, the effective cross section of double parton interactions σ{sub eff} was calculated.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Implications of CoGeNT's new results for dark matter

The CoGeNT Collaboration has recently presented the results of their first 15 months of data, including the measurement of the spectrum of nuclear recoil candidate events, and the time variation of those events. These results appear consistent with the signal anticipated from a relatively light dark matter particle scattering elastically with nuclei. In this paper, we independently analyze the data set collected by CoGeNT and explore the implications of these results for dark matter. We find that the observed spectrum and rate is consistent with originating from dark matter particles with a mass in the range of 4.5-12 GeV and an elastic scattering cross section with nucleons of approximately {approx}10{sup -40} cm{sup 2}. We confirm the conclusion of the CoGeNT Collaboration that the data also includes a somewhat statistically significant (2.7{sigma}) indication of annual modulation, with a phase, period, and amplitude consistent with that predicted for dark matter. CoGeNT's phase is also consistent with the annual modulation reported by the DAMA/LIBRA Collaboration. We also discuss the null results reported by CDMS and XENON100, and comment on the prospects for other experiments to detect a dark matter particle with the properties implied by CoGeNT.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

Dirac particle spin in strong gravitational fields

Dynamics of the Dirac particle spin in general strong gravitational fields is discussed. The Hermitian Dirac Hamiltonian is derived and transformed to the Foldy-Wouthuysen (FW) representation for an arbitrary metric. The quantum mechanical equations of spin motion are found. These equations agree with corresponding classical ones. The new restriction on the anomalous gravitomagnetic moment (AGM) by the reinterpretation of Lorentz invariance tests is obtained.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Toward holographic reconstruction of bulk geometry from lattice simulations

A black hole described in SU(N ) gauge theory consists of N D-branes. By separating one of the D-branes from others and studying the interaction between them, the black hole geometry can be probed. In order to obtain quantitative results, we employ the lattice Monte Carlo simulation. As a proof of the concept, we perform an explicit calculation in the matrix model dual to the black zero-brane in type IIA string theory. We demonstrate this method actually works in the high temperature region, where the stringy correction is large. We argue possible dual gravity interpretations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

A precise electron EDM constraint on CP-odd heavy-quark Yukawas

CP-odd Higgs couplings to bottom and charm quarks arise in many extensions of the standard model and are of potential interest for electroweak baryogenesis. These couplings induce a contribution to the electron EDM. The experimental limit on the latter then leads to a strong bound on the CP-odd Higgs couplings. We point out that this bound receives large QCD corrections, even though it arises from a leptonic observable. We calculate the contribution of CP-odd Higgs couplings to the bottom and charm quarks in renormalisation-group improved perturbation theory at next-to-leading order in the strong interaction, thereby reducing the uncertainty to a few percent.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

NNPDF2.1: Including heavy quark mass effects in NNPDF fits

In this contribution we present the NNPDF2.1 parton distribution functions (PDF) set. The NNPDF2.1 set is a set extracted from a global fit to Deep-Inelastic Scattering (DIS), fixed target Drell-Yan (DY), Electroweak vector boson and inclusive jet cross-sections at colliders data. It is performed using the NNPDF methodology which relies on Monte Carlo techniques for determination of uncertainties and Neural Networks as unbiased interpolants.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Twist 4 Matrix Elements

This work summarizes previous attempts to extract the nucleon expectation value of twist-4 operators from CERN and SLAC data. Speculations about how the new data from Jlab upgrade can reduce the large uncertainties are discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Recent results from atmospheric neutrino analysis at Super-Kamiokande

The atmospheric-neutrino sample at Super-Kamiokande is sensitive to all neutrino oscillation parameters. Our recent analyses focus on the sub-dominant effects which includes unknown parameters. The upper limit to {theta}{sub 13} is set to be sin{sup 2}{theta}{sub 13}<0.066 (< 0.122) at 90% confidence level in case of the normal (inverted) mass hierarchy. We confirm our sample has the sensitivity to the CP phase, {delta}{sub CP}. The mass hierarchy test also is performed. CPT violation in the neutrino oscillation is tested with the atmospheric-neutrino sample. However, our result suggests the CPT conservation.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Neutrino-nucleus scattering in the QE and {Delta}(1232) peak regions

Reliable estimates of neutrino-nucleus reactions in the resonance region play an important role in the on-going and planned neutrino oscillation experiments. We report on our recent analysis on the neutrino-nucleus reaction in the delta excitation region with the use of neutrino pion production amplitudes calculated in a dynamical model of electroweak pion production reactions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Complete Photo-production Experiments

The extraction of resonance parameters from meson photo-reaction data is a challenging effort, that would greatly benefit from the availability of several polarization observables, measured for each reaction channel on both proton and neutron targets. In the aim of obtaining such complete experiments, polarized photon beams and targets have been developed at facilities, worldwide. We report on the latest results from the LEGS and GRAAL collaborations, providing single and double polarization measurements on pseudo-scalar meson photo-production from the nucleon.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Gauge invariance and canonical quantization in the nucleon internal structure

It is unavoidable to deal with the quark and gluon momentum and angular momentum contributions to the nucleon momentum and spin in the study of nucleon internal structure. However, we never have the quark and gluon momentum, orbital angular momentum and gluon spin operators which satisfy both the gauge invariance and the canonical momentum and angular momentum commutation relations. A new set of quark and gluon momentum, orbital angular momentum and spin operators, which satisfy both the gauge invariance and canonical momentum and angular momentum commutation relations, are proposed. The key point to achieve such a proper decomposition is to separate the gauge potential into the pure gauge and the gauge covariant parts. The same conflicts also exist in QED and quantum mechanics and have been solved in the same manner. The impacts of this new decomposition to the nucleon internal structure study are discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Tetraquark states from lattice QCD

Recently there have been considerable interests in studying hadronic states beyond the usual two and three quark configurations. With the renewed experimental interests in {sigma}(600) and the inability of quark model to incorporate too many light scalar mesons, it is quite appropriate to study hadronic states with four quark configurations. Moreover, some of the newly observed charmed hadrons may well be described by four quark configurations. Lattice QCD is perhaps the most desirable tool to adjudicate the theoretical controversy of the scalar mesons and to interpret the structures of the newly observed charmed states. Here we briefly reviewed the lattice studies of four-quark hadrons.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

The nucleon-nucleon system in chiral effective theory

I discuss the conditions under which the application of chiral perturbation theory to the NN potential gives reliable results for NN scattering phase shifts. {sub {chi}P}T also yields a convergent expansion for the deuteron charge operator. For cutoffs <1 GeV, this produces precise predictions for deuterium's quadrupole and charge form factors in the range Q{sup 2}<0.25 GeV{sup 2}.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗