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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 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Neutrino properties in E{sub 6} Multiplication-Sign SU(2){sub F} SUSY GUT with spontaneous CP violation

We examined the neutrino sector in E{sub 6} Multiplication-Sign SU(2){sub F} SUSY GUT with spontaneous CP violation. At a first glance, the discrete symmetry, which is introduced in order to solve the SUSY CP problem, constrains the allowed operators too strongly for the neutrino sector to be consistent with the experimental data, i.e., the {mu} neutrino becomes massless as commented in the previous work. We showed that this issue can be solved if some operators are taken into account. The predictions on the neutrino masses and mixings are the same as the E{sub 6} models, which are consistent with various experiments on the neutrino oscillations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Discovering the Majorana neutrino: The next generation of experiments

The discovery of a Majorana neutrino would be revolutionary with far-reaching consequences in both particle physics and cosmology. The only feasible experiments to determine the Majorana nature of the neutrino are searches for neutrinoless double-beta decay. The next generation of double-beta decay experiments are being prepared. The general goal is to search for neutrinoless double-beta decay throughout the parameter space corresponding to the inverted hierarchy for neutrino mass. There are a several strong proposals for how to achieve this goal. The status of these efforts is reviewed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Hadronization processes in neutrino interactions

Next generation neutrino oscillation experiments utilize details of hadronic final states to improve the precision of neutrino interaction measurements. The hadronic system was often neglected or poorly modelled in the past, but they have significant effects on high precision neutrino oscillation and cross-section measurements. Among the physics of hadronic systems in neutrino interactions, the hadronization model controls multiplicities and kinematics of final state hadrons from the primary interaction vertex. For relatively high invariant mass events, many neutrino experiments rely on the PYTHIA program. Here, we show a possible improvement of this process in neutrino event generators, by utilizing expertise from the HERMES experiment. Finally, we estimate the impact on the systematics of hadronization models for neutrino mass hierarchy analysis using atmospheric neutrinos such as the PINGU experiment.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Radial Regge trajectories for higher {psi}(nS) and {psi}(nD) states

The masses of {Psi}((n + 1){sup 3}S{sub 1}) and {Psi}(n{sup 3}D{sub 1}) are calculated using the relativistic string Hamiltonian with 'linear + gluon-exchange' potential. They occur in the range 4.5-5.8 GeV, in particular, M(3D) = 4.54 GeV, M(5S) = 4.79 GeV, M(4D) = 4.85 GeV are calculated with accuracy {approx}50 MeV. The linear Regge trajectories: M{sup 2}(nS) = M{sup 2}({psi}(4.42)) + 2.91 GeV{sup 2} (n - 4) (n {>=} 4) and M{sup 2}(nD) = M{sup 2}({Psi}(4.54)) + 2.88 GeV{sup 2} (n - 3) (n {>=} 3) are obtained only for higher charmonium states. They have a slope two times larger than that of light mesons and give a good description of calculated masses. These masses are compared with enhancements in some recent e{sup +}e{sup -} experiments.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

ZFOURGE/CANDELS: ON THE EVOLUTION OF M* GALAXY PROGENITORS FROM z = 3 TO 0.5

Galaxies with stellar masses near M* contain the majority of stellar mass in the universe, and are therefore of special interest in the study of galaxy evolution. The Milky Way (MW) and Andromeda (M31) have present-day stellar masses near M*, at 5 × 10{sup 10} M {sub ☉} (defined here to be MW-mass) and 10{sup 11} M {sub ☉} (defined to be M31-mass). We study the typical progenitors of these galaxies using the FOURSTAR Galaxy Evolution Survey (ZFOURGE). ZFOURGE is a deep medium-band near-IR imaging survey, which is sensitive to the progenitors of these galaxies out to z ∼ 3. We use abundance-matching techniques to identify the main progenitors of these galaxies at higher redshifts. We measure the evolution in the stellar mass, rest-frame colors, morphologies, far-IR luminosities, and star formation rates, combining our deep multiwavelength imaging with near-IR Hubble Space Telescope imaging from Cosmic Near-IR Deep Extragalactic Legacy Survey (CANDELS), and Spitzer and Herschel far-IR imaging from Great Observatories Origins Deep Survey-Herschel and CANDELS-Herschel. The typical MW-mass and M31-mass progenitors passed through the same evolution stages, evolving from blue, star-forming disk galaxies at the earliest stages to redder dust-obscured IR-luminous galaxies in intermediate stages and to red, more quiescent galaxies at their latest stages. The progenitors of the MW-mass galaxies reached each evolutionary stage at later times (lower redshifts) and with stellar masses that are a factor of two to three lower than the progenitors of the M31-mass galaxies. The process driving this evolution, including the suppression of star formation in present-day M* galaxies, requires an evolving stellar-mass/halo-mass ratio and/or evolving halo-mass threshold for quiescent galaxies. The effective size and SFRs imply that the baryonic cold-gas fractions drop as galaxies evolve from high redshift to z ∼ 0 and are strongly anticorrelated with an increase in the Sérsic index. Therefore, the growth of galaxy bulges in M* galaxies corresponds to a rapid decline in the galaxy gas fractions and/or a decrease in the star formation efficiency.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2011

Neutral Current Elastic Interactions in MiniBooNE

Neutral Current Elastic (NCE) interactions in MiniBooNE are discussed. In the neutrino mode MiniBooNE reported: the flux averaged NCE differential cross section as a function of four-momentum transferred squared, an axial mass (M{sub A}) measurement, and a measurement of the strange quark spin content of the nucleon, {Delta}s. In the antineutrino mode we present the background-subtracted data which is compared with the Monte Carlo predictions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

The proton structure in the region of high x{sub B}

The hadron structure has been intensively studied over the last 20 years, but mostly in regions of medium and low Bjorken x. On the other hand, there are large experimental projects (Jlab 12 GeV and CERN COMPASS-II) that will produce a lot of data on lepton-nucleon deep inelastic scattering in kinematics regions not study yet, like the region where the parton carries a large momentum fraction of the parent nucleon. It is well known from literature that the high x{sub B} region is quite problematic, because, among other things, one needs to deal with the nucleon resonance region. To avoid this region, one should have an invariant mass for the system greater than 2 GeV. One can do this by lowering the values for x{sub B} (irrelevant for our current research), or by decreasing the value of Q{sup 2}. In the later case, there are not many experimental data and the projects mentioned will try to fill this gap. When one is in the low Q{sup 2} region, an extra problem appears: corrections in the form of M{sup 2}/Q{sup 2}, usually disregarded in the OPE expansion, have now to be taken care of. These corrections are referred to as Target Mass Corrections (TMC). Our work aims to find clean ways to separate these TMC from the experimental data and thus related them to the usual structure functions, measured in other experiments, with are free of effects coming from the finite value of the nucleon mass.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Fermionic dark matter in a simple t-channel model

We consider a fermionic dark matter (DM) particle in renormalizable Standard Model (SM) gauge interactions in a simple t-channel model. The DM particle interactions with SM fermions is through the exchange of scalar and vector mediators which carry colour or lepton number. In the case of coloured mediators considered in this study, we find that if the DM is thermally produced and accounts for the observed relic density almost the entire parameter space is ruled out by the direct detection observations. The bounds from the monojet plus missing energy searches at the Large Hadron Collider are less stringent in this case. In contrast for the case of Majorana DM, we obtain strong bounds from the monojet searches which rule out DM particles of mass less than about a few hundred GeV for both the scalar and vector mediators.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Deconfinement phase transition in a finite volume in the presence of massive particles

We study the QCD deconfinement phase transition from a hadronic gas to a Quark-Gluon Plasma, in the presence of massive particles. Especially, the influence of some parameters as the finite volume, finite mass, flavors number N{sub f} on the transition point and on the order of the transition is investigated.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Open parabosonic string theory between two parallel Dp-branes

We investigate an open parabosonic string theory between two parallel Dp-branes. The spectrum is constructed and the partition function is derived. A common chord between the development of this latter and the degeneracy of the states for each mass level is obtained. The theory is consistent and with no tachyon. The Virasoro algebra is derived and compared to the one of the ordinary case.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

PINGU sensitivity to neutrino mass hierarchy

Determination of the neutrino mass hierarchy (NMH) is among the most fundamental questions in particle physics. Recent measurements of 1) a large mixing angle between the first and the third neutrino mass eigenstates and 2) the first observation of atmospheric neutrino oscillations at tens of GeV with neutrino telescopes, open the intriguing new possibility to exploit matter effects in neutrino oscillation to determine the neutrino mass hierarchy. A further extension of IceCube/DeepCore called PINGU (Precision IceCube Next Generation Upgrade) has been recently envisioned with the ultimate goal to measure neutrino mass hierarchy. PINGU would consist of additional IceCube-like strings of detectors deployed in the deepest and cleanest ice in the center of IceCube. More densely deployed instrumentation would provide a threshold substantially below 10 GeV and enhance the sensitivity to the mass hierarchy signal in atmospheric neutrinos. Here we discuss an estimate of the PINGU sensitivity to the mass hierarchy determined using an approximation with an Asimov dataset and an oscillation parameter fit.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Future atmospheric neutrino measurements with PINGU

Neutrino oscillations, first measured in 1998 via atmospheric neutrinos, have provided the only current direct evidence for physics beyond the Standard Model of Elementary Particles. The full neutrino mixing, described by six parameters, has been measured in the last decade with the exception of the charge-parity phase and the ordering of the mass eigenstates (the neutrino mass hierarchy – NMH). A relatively large mixing-angle between the first and third mass eigenstates has opened the possibility of measuring the mass hierarchy via atmospheric neutrinos using very large volume detectors. A leading proposal to perform this measurement is the future low-energy extension to the IceCube–DeepCore detector, called PINGU (the Precision IceCube Next Generation Upgrade). By increasing the photocathode density in the DeepCore region, it is possible to lower the energy threshold in the fiducial volume to the region that is affected by the MSW [1, 2], and thus permits extraction of the hierarchy. Here we discuss the design of the PINGU detector, its sensitivity to the mass hierarchy (approximately 3σ in 3.5 years) and measurements of ν{sub μ} disappearance and ν{sub τ} appearance.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Sterile neutrinos for warm dark matter and the reactor anomaly in flavor symmetry models

We construct a flavor symmetry model based on the tetrahedral group A{sub 4} in which the right-handed neutrinos from the seesaw mechanism can be both keV warm dark matter particles and eV-scale sterile neutrinos. This is achieved by giving the right-handed neutrinos appropriate charges under the same Froggatt-Nielsen symmetry responsible for the hierarchy of the charged lepton masses. We discuss the effect of next-to-leading order corrections to deviate the zeroth order tri-bimaximal mixing. Those corrections have two sources: (i) higher order seesaw terms, which are important when the seesaw particles are eV-scale, and (ii) higher-dimensional effective operators suppressed by additional powers of the cut-off scale of the theory. Whereas the mixing angles of the active neutrinos typically receive corrections of the same order, the mixing of the sterile neutrinos with the active ones is rather stable as it is connected with a hierarchy of mass scales. We also modify an effective A{sub 4} model to incorporate keV-scale sterile neutrinos.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2012

Enhanced gamma ray signals in cosmic proton-wimp collisions due to hadronization

In this paper, we investigate the gamma ray signal produced from dark matter collisions with high energy cosmic protons. Notably, we extend past results by including important hadronization effects. Showering and hadronization produces a high multiplicity of photons from the decays of hadrons, whose rate is not suppressed by the fine structure constant. Notably, proton remnants that do not participate in hard scattering, can produce a large rate of photons in the forward direction. These effects significantly enhance the photon rate and alter the energy and angular distributions compared to previous results which used only parton level calculations. Due to this modification, the gamma ray signal from the nearby active galactic nuclei Centaurus A is potentially testable in future Fermi-LAT and HESS measurements, for a dark matter mass and coupling consistent with current XENON100 bounds.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Higgs bosons in standard model extensions

Several possibilities for extending the scalar sector of the Standard Model are considered. The conditions of calculation of Higgs bosons masses in the Next-to-Minimal Supersymmetric Standard Model are discussed. The probable limits on mass parameters of Higgs bosons are analyzed. The role of minimum conditions as a physical criterion in a model with an extended scalar sector is defined.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Calculation of the {pi}{sup +}{Sigma}{sup +} and {pi}{sup +}{Xi}{sup 0} Scattering Lengths in Lattice QCD

The {pi}{sup +}{Sigma}{sup +} and {pi}{sup +}{Xi}{sup 0} scattering lengths were calculated in mixed-action Lattice QCD with domain-wall valence quarks on the asqtad-improved coarse MILC configurations at four light-quark masses, and at two light-quark masses on the fine MILC configurations. Heavy Baryon Chiral Perturbation Theory with two and three flavors of light quarks was used to perform the chiral extrapolations. To NNLO in the three-flavor chiral expansion, the kaon-baryon processes that were investigated show no signs of convergence. Using the two-flavor chiral expansion for extrapolation, the pion-hyperon scattering lengths are found to be a{sub {pi}}{sup +}{sub {Sigma}}{sup +} = -0.197{+-}0.017 fm, and a{sub {pi}}{sup +}{sub {Xi}}{sup 0} = -0.098{+-}0.017 fm, where the comprehensive error includes statistical and systematic uncertainties.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Juelich-Georgia meson-baryon model

Meson-baryon scattering and photon-nucleon reactions are described in a coupled-channel approach for energies below 2 GeV. Poles and residues of the reaction amplitudes are obtained by analytical continuation. The dependence of the resonance poles on the pion mass is investigated.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Future reactor experiments

The non-zero neutrino mixing angle θ{sub 13} has been discovered and precisely measured by the current generation short-baseline reactor neutrino experiments. It opens the gate of measuring the leptonic CP-violating phase and enables the neutrino mass ordering. The JUNO and RENO-50 proposals aim at resolving the neutrino mass ordering using reactors. The experiment design, physics sensitivity, technical challenges as well as the progresses of those two proposed experiments are reviewed in this paper.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗