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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 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Precision spectroscopy of kaonic {sup 3}He X-rays at J-PARC

We will measure the X-rays from kaonic {sup 3}He 3d {yields} 2p transition with a precision below 2 eV. It can provide crucial information on the kaon-nucleus strong interaction. The experiment (J-PARC E17) will be performed as Day-1, which is one of the first experiments in the J-PARC hadron facility in the year 2011. An overview and the present status of the J-PARC E17 experiment are described.

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

Studies of Partonic Transverse Momentum and Spin Structure of the Nucleon at HERMES

The investigation of the partonic degrees of freedom beyond collinear approximation (3D description) has been gained increasing interest in the last decade. At the HERMES experiment, azimuthal single-spin asymmetries of pions and charged kaons produced in semi-inclusive deep-inelastic scattering of electrons and positrons off a transversely (polarized) hydrogen and deuterium target have been measured. Such asymmetries provide new insights on crucial aspects of the parton dynamics. By measuring various hadron types in the initial and final states, flavor sensitivity is achieved. Evidence is reported of the poorly known transversity function and of naive-T-odd transverse-momentum-dependent parton distribution functions related to spin-orbit effects. Evidence of spin-orbit effects in quark fragmentation is also observed, which are opposite in sign for favored and disfavored processes.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

NJL-jet model calculation of quark fragmentation to hadrons

A description of fragmentation processes of quarks into hadrons is presented in the framework of the recently developed NJL-jet model, where the momentum and isospin sum rules are satisfied naturally. We present the results for pion, kaon and nucleon fragmentation functions, and compare the results with the empirical functions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

The NA62 RICH Detector

The goal of the CERN NA62 experiment is to measure the ultra-rare (Branching Ratio, BR {approx}10{sup -10}) charged kaon decay K{sup +}{yields}{pi}{sup +}vv-bar with an accuracy of 10%. The main background, the K{sup +}{yields}{mu}{sup +}v decay (BR {approx}63%), must be suppressed by a rejection factor of 4x10{sup -13}. This can be accomplished using a combination of several methods and detectors. The RICH detector will contribute to this task and will also provide the pion crossing time with a resolution of the order of 100 ps. The details of the RICH project as well as the results from two different test beams performed on a RICH prototype will be presented.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Twist-3 predictions for single spin asymmetry for light-hadron productions at RHIC

We present several predictions for the single spin asymmetry for the {pi}, K, and {eta}-meson productions at RHIC kinematics using the twist-3 quark-gluon correlation functions determined from our analysis of RHIC data. After discussing the P{sub T}-dependence of A{sub N}, we give predictions for A{sub N} for pions and kaons at {radical}(S) = 500 GeV and A{sub N} for the {eta}-meson at {radical}(S) = 200 GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Electromagnetic polarizabilities: Lattice QCD in background fields

Chiral perturbation theory makes definitive predictions for the extrinsic behavior of hadrons in external electric and magnetic fields. Near the chiral limit, the electric and magnetic polarizabilities of pions, kaons, and nucleons are determined in terms of a few well-known parameters. In this limit, hadrons become quantum mechanically diffuse as polarizabilities scale with the inverse square-root of the quark mass. In some cases, however, such predictions from chiral perturbation theory have not compared well with experimental data. Ultimately we must turn to first principles numerical simulations of QCD to determine properties of hadrons, and confront the predictions of chiral perturbation theory. To address the electromagnetic polarizabilities, we utilize the background field technique. Restricting our attention to calculations in background electric fields, we demonstrate new techniques to determine electric polarizabilities and baryon magnetic moments for both charged and neutral states. As we can study the quark mass dependence of observables with lattice QCD, the lattice will provide a crucial test of our understanding of low-energy QCD, which will be timely in light of ongoing experiments, such as at COMPASS and HI gamma S.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2012

The search for QCD in nuclei: A Jefferson lab perspective

We discuss the phenomenon of Color Transparency, and give an overview of the extensive experimental searches for signatures of QCD in nuclei at Jefferson Lab, Hall-C. The results from protons, pions and kaons are compared with each other and with results from hadron scattering.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2012

Strangeness electroproduction on the nucleon at CLAS

High-precision measurements of strange particle production from both proton and neutron targets are a core part of the physics program with the CLAS spectrometer in Hall B at Jefferson Laboratory. Measurements have been carried out at beam energies up to 6 GeV in experiments with polarized beams and polarized targets. This talk will focus on the electroproduction measurements that have been completed, which include cross sections and hyperon polarization observables for K{sup +}Y (Y = {Lambda}{Sigma}{sup 0}) final states over a broad kinematic range in momentum transfer Q{sup 2} and invariant energy W, while spanning nearly the full kaon center-of-mass angular range. These data in the strangeness sector are necessary to better understand the different production mechanisms for {Lambda} and {Sigma} hyperons and to disentangle the different resonant and non-resonant amplitudes in the intermediate state. The usefulness of the CLAS electroproduction data as part of a coupled-channel model fit will be discussed as well as an outlook of this program for the future.

43 PARTICLE ACCELERATORS↗
DOE OSTI2013

Searching for an invisible dark photon with DarkLight

The DarkLight experiment at Jefferson Lab is designed to search for a new U(1) vector boson A' in the mass range 10-100 MeV through its decay A′→e{sup +}e{sup −}. We will show that DarkLight is also sensitive to an A' decaying to invisible final states, but because of QED backgrounds, such a search is only feasible with photon detection. Surprisingly, pileup can be mitigated with a cut on the sign of the missing invariant mass-squared. We give the DarkLight reach for the invisible search assuming a nominal two-month running time, and compare to constraints from anomalous magnetic moments and rare kaon decays.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

A sterile neutrino at MiniBooNE and IceCube

We discuss the possibility that a sterile neutrino of mass around 50 MeV slightly mixed with the muon flavor may be the origin of the MiniBooNE anomaly. We show that its production in the atmosphere in a fraction of kaon decays would imply an excess of contained showers at IceCube from down-going and near-horizontal directions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

Neutrinos from charm production in the atmosphere

Atmospheric neutrinos are produced in interactions of cosmic rays with Earth's atmosphere. At very high energy, the contribution from semi-leptonic decays of charmed hadrons, known as the prompt neutrino flux, dominates over the conventional flux from pion and kaon decays. This is due to the very short lifetime of the charmed hadrons, which therefore do not lose energy before they decay. The calculation of this process is difficult because the Bjorken-x at which the parton distribution functions are evaluated is very small. This is a region where QCD is not well understood, and large logarithms must be resummed. Available parton distribution functions are not known at such small x and extrapolations must be made. Theoretically, the fast rise of the structure functions for small x ultimately leads to parton saturation. This contribution describes the 'ERS' [1] calculation of the prompt neutrino flux, which includes parton saturation effects in the QCD production cross section of charm quarks. The ERS flux calculation is used by e.g. the IceCube collaboration as a standard benchmark background. We are now updating this calculation to take into account the recent LHC data on the charm cross section, as well as recent theoretical developments in QCD. Some of the issues involved in this calculation are described.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Medium effects in proton-induced strangeness production

We discuss recent advances of the HADES collaboration in the sector of in-medium strangeness physics, in particular the measurement of neutral kaons produced in proton-niobium reactions at 3.5 GeV.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

Indirect search for dark matter in the Sun

If dark matter is be captured in the Sun and self-annihilate, evidence of this process might be observable on the Earth in form of a neutrinos, which are copiously produced in the annihilation process. We discuss a novel signature of dark matter annihilations in the Sun that originates from monoenergetic neutrinos produced in pion and kaon decays. Based on this signature we find competitive sensitivities for the detection of dark matter at present and next-generation neutrino detectors.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Diffuse emission of high-energy neutrinos from gamma-ray burst fireballs

Gamma-ray bursts (GRBs) have been suggested as possible sources of the high-energy neutrino flux recently detected by the IceCube telescope. We revisit the fireball emission model and elaborate an analytical prescription to estimate the high-energy neutrino prompt emission from pion and kaon decays, assuming that the leading mechanism for the neutrino production is lepto-hadronic. To this purpose, we include hadronic, radiative and adiabatic cooling effects and discuss their relevance for long- (including high- and low-luminosity) and short-duration GRBs. The expected diffuse neutrino background is derived, by requiring that the GRB high-energy neutrino counterparts follow up-to-date gamma-ray luminosity functions and redshift evolutions of the long and short GRBs. Although dedicated stacking searches have been unsuccessful up to now, we find that GRBs could contribute up to a few % to the observed IceCube high-energy neutrino flux for sub-PeV energies, assuming that the latter has a diffuse origin. Gamma-ray bursts, especially low-luminosity ones, could however be the main sources of the IceCube high-energy neutrino flux in the PeV range. While high-luminosity and low-luminosity GRBs have comparable intensities, the contribution from the short-duration component is significantly smaller. Our findings confirm the most-recent IceCube results on the GRB searches and suggest that larger exposure is mandatory to detect high-energy neutrinos from high-luminosity GRBs in the near future.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2011

Spectroscopic investigation of Lambda hypernuclei in the wide mass region using the (e, e-prime K+) reaction

The third generation spectroscopic study of {Lambda} hypernuclei using (e,e'K{sup +}) reaction (JLab E05-115) was performed at JLab Hall-C in 2009. The experiment introduced the newly developed high-resolution electron spectrometer (HES) with the existing high-resolution kaon spectrometer (HKS). Experimental configuration, conditions, spectrometer designs and current status of analysis are presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2026

Axionlike particles and sterile neutrinos solve the 𝐵 → 𝐾⁢$𝜈⁢\bar{𝜈}$ and 𝐵 → 𝜋⁢𝐾 puzzles

The recent measurement of the branching ratio of 𝐵 + → 𝐾 + +inv (where “inv” denotes invisible states) by the Belle II Collaboration is enhanced relative to the standard model expectation by 2.7⁢𝜎. An older puzzle persists in measurements of the branching ratios and 𝐶⁢𝑃 asymmetries of 𝐵 → 𝜋⁢𝐾 decays. We address these two anomalies in flavor-changing neutral current 𝐵 decays, with a short-lived axionlike particle (ALP) with mass close to that of the 𝜋 0 . In the model with the minimum number of new couplings, the ALP has couplings to the photon, top quark and a heavy sterile neutrino. The ALP contributes to the 𝐵 → 𝜋 0 ⁢𝐾 decays by mixing with the 𝜋 0 . It contributes to 𝐵 + → 𝐾 + + inv by its off-shell coupling to sterile neutrino pairs. The model can explain the excess in the total rate, but not the observed distribution of signal events. We make predictions for all 𝐵 → 𝐾 (*) + inv modes and for the rare kaon decays, 𝐾 + → 𝜋 + + inv and 𝐾 𝐿 → 𝜋 0 + inv. We find an appreciable contribution to the magnetic moment of the muon, and negligible contributions to the magnetic moment of the electron and 𝑏 → 𝑠⁢𝑒 + ⁢𝑒 − .

axion-like particles↗
DOE OSTI2011

Measurement of Partial Branching Fractions of Inclusive Charmless B Meson Decays to K , K0, and pi

The authors present measurements of partial branching fractions of B {yields} K{sup +}X, B {yields} K{sup 0} X, and B {yields} {pi}{sup +}X, where X denotes any accessible final state above the endpoint for B decays to charmed mesons, specifically for momenta of the candidate hadron greater than 2.34 (2.36) GeV for kaons (pions) in the B rest frame. These measurements are sensitive to potential new-phisics particles which could enter the b {yields} s(d) loop transitions. The analysis is performed on a data sample consisting of 383 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II e{sup +}e{sup -} asymmetric energy collider. The results are in agreement with standard model predictions and exclude large enhancements of the inclusive branching fraction due to sources of new physics.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗