Search NASA⌕ Search

SEARCH · Search NASA

Results for “elementary particles”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

The radioactive source calibration system of the PROSPECT reactor antineutrino detector

The Precision Reactor Oscillation and Spectrum (PROSPECT) Experiment is a reactor neutrino experiment created to search for sterile neutrinos with a mass on the order of 1 eV/c 2 and to measure the spectrum of electron antineutrinos from a highly-enriched 235 U nuclear reactor. The PROSPECT detector consists of an 11 by 14 array of optical segments in 6 Li-loaded liquid scintillator at the High Flux Isotope Reactor in Oak Ridge National Laboratory. Antineutrino events are identified via inverse beta decay and read out by photomultiplier tubes located at the ends of each segment. The detector response is characterized using a radioactive source calibration system. Here, we describe the design, operation, and performance of the PROSPECT source calibration system.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Light Cone Dynamics and EMC Effects in the Extraction of F{sub 2n} at Large Bjorken x

We discuss theoretical issues related to the extraction of deep inelastic (DIS) structure function of neutron from inclusive DIS scattering off the deuteron at large Bjorken x. Theoretical justification is given to the consideration of only pn component of the deuteron wave function and consistency with both the baryonic number and light-cone momentum conservation sum rules. Next we discuss the EMC type effects and argue that in all cases relevant to the nuclear DIS reactions at large x the main issue is the medium modification of the properties of bound nucleon rather than the non-nucleonic components like pions. We give brief description of the color screening model of EMC and within this model we estimate uncertainties in the extraction of the neutron DIS structure function at large x. We emphasize also that these uncertainties are rather ''model independent'' since any theoretical framework accounting for the medium modification is proportional to the magnitude of the virtuality of bound nucleon which increases with an increase of x.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Recent progress on nuclear parton distribution functions

We report current status of global analyses on nuclear parton distribution functions (NPDFs). The optimum NPDFs are determined by analyzing high-energy nuclear reaction data. Due to limited experimental measurements, antiquark modifications have large uncertainties at x > 0.2 and gluon modifications cannot be determined. A nuclear modification difference between u and d quark distributions could be an origin of the long-standing NuTeV sin{sup 2}{theta}{sub w} anomaly. There is also an issue of nuclear modification differences between the structure functions of charged-lepton and neutrino reactions. Next, nuclear clustering effects are discussed in structure functions F{sub 2}{sup A} as a possible explanation for an anomalous result in the {sup 9}Be nucleus at the Thomas Jefferson National Accelerator Facility (JLab). Last, tensor-polarized quark and antiquark distribution functions are extracted from HERMES data on the polarized structure function b{sub 1} of the deuteron, and they could be used for testing theoretical models and for proposing future experiments, for example, the one at JLab. Such measurements could open a new field of spin physics in spin-one hadrons.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Some attempts to explain the MINOS anomaly

Some attempts which were made to explain the MINOS anomaly are critically discussed. They include the non-standard neutral current-neutrino interaction and the (3+1)-scheme with a sterile neutrino.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Prospects and Challenges for a Large Water Cherenkov Detector for LBNE

The Long Baseline Neutrino Experiment (LBNE) is a proposed experiment that would send a beam of muon neutrinos from Fermilab to the DUSEL (Deep Underground Science and Engineering Laboratory) facility in South Dakota, a 1300 km baseline. One possible configuration for the far detector is one or more large water Cherenkov modules with a fiducial mass of at least 100 kilotons each. The prospects and challenges of such a detector, including the current design, will be presented.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Non-Standard v-Interactions at a Neutrino Factory: Correlation and CP violation effects

The so-called Non-Standard v-Interactions in propagation is a widely studied topic in the Neutrino Factory literature. However, special attention has not been paid to the possible correlation effects among the whole set of parameters arising in this context (standard and non-standard ones). Here we will focus on these correlation effects analysing the performance of three different Neutrino Factory setups. In addition, we explore the new avenues of CP violation coming from this sort of Non-Standard v-Interactions with the same perspective, in other words, studying the relation among the several CP-phases involved.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Low Energy Neutrino and Dark Matter Physics with sub-keV Germanium Detectors

A TEXONO collaboration research program on low energy neutrino and dark matter physics is going on at the Kuo-Sheng Neutrino Laboratory (KSNL). Collaboration main goals are to measure the neutrino-nucleus coherent scattering cross section, neutrino magnetic moments, and the searches of WIMP dark matter. To achieve these goals various prototype detectors and their sub-keV background are under study. A threshold of 220 eV was achieved with prototype detectors at the KSNL. New limits were set for WIMPs with mass between 3-6 GeV. Data are being taken with a 500 g Point Contact Germanium detector, where a threshold of {approx}350 eV was demonstrated. A 20 g ULEGe detector is taking data at CJPL in Sichuan, China.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Transverse-momentum-dependent parton distributions (TMDs)

Transverse-momentum-dependent parton distributions (TMDs) provide three-dimensional images of the partonic structure of the nucleon in momentum space. We made impressive progress in understanding TMDs, both from the theoretical and experimental point of view. This brief overview on TMDs is divided in two parts: in the first, an essential list of achievements is presented. In the second, a selection of open questions is discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Regge-plus-resonance predictions for neutral-kaon photoproduction from the deuteron

We present a Regge-inspired effective-Lagrangian framework for neutral-kaon photo-production from the deuteron. Quasi-free kaon production is investigated using the Regge-plus-resonance elementary operator within the relativistic plane-wave impulse approximation. The Regge-plus-resonance model was developed to describe photoinduced and electroinduced charged-kaon production off protons. We show how this elementary operator can be transformed to account for the production of neutral kaons from both protons and neutrons. Our results compare favourably to the sole {sup 2}H({gamma},K{sup 0})YN dataset published to date.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Heavy quark spin symmetry and heavy hadronic molecules

In the heavy quark limit there is heavy quark spin symmetry. As a consequence, heavy hadrons or heavy quarkonia form spin multiplets. We argue that due to the symmetry, also heavy flavor hadronic molecules form spin multiplets, and the hyperfine splittings are the same as those between the heavy hadrons which are components of the molecules. Hence it provides a method to identify the nature of heavy hadronic molecules. As an example, we give predictions of the properties of an {eta}{sub c}{sup '}f{sub 0}(980) bound state assuming the Y(4660) to be an S-wave {psi}{sup '}f{sub 0}(980) shallow bound state. We also show that the enhancement observed in the {Lambda}{sub c}{sup +}{Lambda}{sub c}{sup -} invariant mass distribution might be the Y(4660).

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Photoproduction of Mesons off Light Nuclei

During the last few years, a series of experiments has been done at the ELSA accelerator in Bonn with the Crystal Barrel/TAPS setup and at the MAMI accelerator in Mainz with the Crystal Ball/TAPS setup. Photoproduction of light mesons off the deuteron and {sup 3}He-nuclei has been studied in detail. We will report some of the most interesting results.A completely unexpected finding, is the pronounced structure in the excitation function of the {gamma}n {yields} n{eta} reaction around 1 GeV, which has no counterpart for the proton. Recent measurements at GRAAL, Sendai, ELSA [1] and MAMI estimate it's width below 50 MeV, which would be extremely narrow for a nucleon resonance at this excitation energy. In the experiment with the {sup 3}He target, special attention was given to the threshold behavior of the {gamma}He{sup 3} reactions in view of possible indications for the formation of (quasi-)bound {eta}-nucleus states, so-called {eta}-mesic nuclei. A very strong threshold enhancement of coherent {eta}-photoproduction off {sup 3}He was found. In a new experiment, this reaction was measured with much better statistical accuracy compared to an earlier experiment at MAMI-B using the TAPS detector [2].

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Status Report of J-PARC E19

The aim of the J-PARC E19 experiment is to search for the pentaquark {Theta}{sup +} in the {pi}{sup -}+p{yields}K{sup -}+X reaction. The expected sensitivity reaches 75 {mu}b/sr in the laboratory frame. This is the first experimental program to be performed at the J-PARC Hadron Facility. The spectrometer has been completed and successfully operated. The physics run has started on October 2010. As a first step, we accumulated the statistics which is enough to confirm the existence of the {Theta}{sup +} assuming the cross section of 1.9 {mu}b/sr reported in the past KEK experiment. We plan to study the energy dependence of the cross section for beamtime from Spring 2011.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

N-{Delta} weak transition

A short review of the Rein-Sehgal and isobar models is presented. The attention is focused on the nucleon-{Delta}(1232) weak transition form-factors. The results of the recent re-analyses of the ANL and BNL bubble chamber neutrino-deuteron scattering data are discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Entanglement of Quasielastic Scattering and Pion Production

The extraction of neutrino oscillation parameters requires the determination of the neutrino energy from observations of the hadronic final state. Here we discuss the difficulties connected with this energy reconstruction for the ongoing experiments MiniBooNE and T2K. We point out that a lower limit to the uncertainty in the reconstructed energy from Fermi motion alone amounts to about 15%. The entanglement of very different elementary processes, in this case quasielastic scattering and pion production, in the actual observables leads to considerably larger errors. We discuss the sensitivity of the energy reconstruction to detection techniques and experimental acceptances. We also calculate the misidentification cross section for electron appearance in the T2K experiment due to neutral pion production.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Highlights from NuInt11

We have seen significant advancement in our understanding of few-GeV neutrino-nucleus interactions since the time of the first NuInt workshop in 2001. Now ten years later, we reflect on our progress. Highlights from the NuInt11 workshop are presented along with some suggestions for future directions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

High precision spectrometers for very forward protons in CMS

We plan to add proton tracking and timing detectors at $z$ = 240-250 m on both sides of CMS to study central exclusive production, with one or both protons measured, and single diffraction. They provide measurements of $p+p \rightarrow p + X + p$, where $X = Z, H, W^+W^-$ and multiparticle states (with or without jets), as well as single high mass diffraction in low pile-up runs.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗