LHC limits on the top-Higgs in models with strong top-quark dynamics
Not Available
Chivukula, R. Sekhar↗
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.
Active to Sterile Neutrino Mixing Limits from Neutral-Current Interactions in MINOS
Results are reported from a search for active to sterile neutrino oscillations in the MINOS long-baseline experiment, based on the observation of neutral-current neutrino interactions, from an exposure to the NuMI neutrino beam of 7.07x10{sup 20} protons on target. A total of 802 neutral-current event candidates is observed in the Far Detector, compared to an expected number of 754{+-}28(stat){+-}37(syst) for oscillations among three active flavors. The fraction f{sub s} of disappearing {nu}{sub {mu}} that may transition to {nu}{sub s} is found to be less than 22% at the 90% C.L.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
New Parity-Violating Muonic Forces and the Proton Charge Radius
The recent discrepancy between proton charge radius measurements extracted from electron-proton versus muon-proton systems is suggestive of a new force that differentiates between lepton species. We identify a class of models with gauged right-handed muon number, which contains new vector and scalar force carriers at the {approx}100 MeV scale or lighter, that is consistent with observations. Such forces would lead to an enhancement by several orders-of-magnitude of the parity-violating asymmetries in the scattering of low-energy muons on nuclei. The relatively large size of such asymmetries, O(10{sup -4}), opens up the possibility for new tests of parity violation in neutral currents with existing low-energy muon beams.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Bounds on an Anomalous Dijet Resonance in W+jets Production in pp Collisions at {radical}(s)=1.96 TeV
We present a study of the dijet invariant mass spectrum in events with two jets produced in association with a W boson in data corresponding to an integrated luminosity of 4.3 fb{sup -1} collected with the D0 detector at {radical}(s)=1.96 TeV. We find no evidence for anomalous resonant dijet production and derive upper limits on the production cross section of an anomalous dijet resonance recently reported by the CDF Collaboration, investigating the range of dijet invariant mass from 110 to 170 GeV/c{sup 2}. The probability of the D0 data being consistent with the presence of a dijet resonance with 4 pb production cross section at 145 GeV/c{sup 2} is 8x10{sup -6}.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Mass of the H Dibaryon
Recent lattice QCD calculations have reported evidence for the existence of a bound state with strangeness -2 and baryon number 2 at quark masses somewhat higher than the physical values. By developing a description of the dependence of this binding energy on the up, down and strange quark masses that allows a controlled chiral extrapolation, we explore the hypothesis that this state is to be identified with the H dibaryon. Taking as input the recent results of the HAL and NPLQCD Collaborations, we show that the H dibaryon is likely to be unbound by 13{+-}14 MeV at the physical point.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Comment on ''High-Precision Determination of the Electric and Magnetic Form Factors of the Proton''
A Comment on the Letter by J. C. Bernauer et al., Phys. Rev. Lett. 105, 242001 (2010). The authors of the Letter offer a Reply.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Search for CP Violation in {tau}{sup {+-}}{yields}K{sub S}{sup 0}{pi}{sup {+-}}{nu}{sub {tau}} Decays at Belle
We report on a search for CP violation in {tau}{sup {+-}}{yields}K{sub S}{sup 0}{pi}{sup {+-}}{nu}{sub {tau}} decays using a data sample of 699 fb{sup -1} collected by the Belle experiment at the KEKB electron-positron asymmetric-energy collider. The CP asymmetry is measured in four bins of the invariant mass of the K{sub S}{sup 0}{pi}{sup {+-}} system and found to be compatible with zero with a precision of O(10{sup -3}) in each mass bin. Limits for the CP violation parameter Im({eta}{sub S}) are given at the 90% confidence level. These limits are |Im({eta}{sub S})|<0.026 or better, depending on the parametrization used to describe the hadronic form factors, and improve upon previous limits by 1 order of magnitude.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Probing the High Momentum Component of the Deuteron at High Q{sup 2}
The {sup 2}H(e,e{sup '}p)n cross section at a momentum transfer of 3.5 (GeV/c){sup 2} was measured over a kinematical range that made it possible to study this reaction for a set of fixed missing momenta as a function of the neutron recoil angle {theta}{sub nq} and to extract missing momentum distributions for fixed values of {theta}{sub nq} up to 0.55 GeV/c. In the region of 35 deg. {<=}{theta}{sub nq}{<=}45 deg. recent calculations, which predict that final-state interactions are small, agree reasonably well with the experimental data. Therefore, these experimental reduced cross sections provide direct access to the high momentum component of the deuteron momentum distribution in exclusive deuteron electrodisintegration.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Search for Invisible Axion Dark Matter in the 3.3 – 4.2 μ eV Mass Range
Not Available
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
'Photonic jets' from dielectric microaxicons
We consider a specific spatially localised light structure, namely, a 'photonic jet' formed in the near field upon scattering of an optical wave in a dielectric micron particle. Dimensional parameters and intensity of a photonic jet from microaxicons of different spatial orientation are studied theoretically. It is found for the first time that an axicon-generated photonic jet has in this case a substantially larger length compared with the case of a jet formed on a spherical particle. (scattering of light)
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Transient radiation from a ring resonant medium excited by an ultrashort superluminal pulse
We report some specific features of transient radiation from a periodic spatially modulated one-dimensional medium with a resonant response upon excitation by an ultrashort pulse. The case of ring geometry (with particle density distributed along the ring according to the harmonic law) is considered. It is shown that the spectrum of scattered radiation contains (under both linear and nonlinear interaction), along with the frequency of intrinsic resonance of the medium, a new frequency, which depends on the pulse velocity and the spatial modulation period. The case of superluminal motion of excitation, when the Cherenkov effect manifests itself, is also analysed. (laser applications and other topics in quantum electronics)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Hadronic particles made of multi-{rho}(770) mesons
We summarize the work [1] where we studied the few body system made of several {rho}(770) mesons. Based on the very strong interaction of two {rho}(770) vector mesons in spin 2 and isospin 0, we show that the resonances {rho}3(1690)(3{sup --}), f4(2050)(4{sup ++}), {rho}5(2350)(5{sup --}) and f6(2510)(6{sup ++}) can be interpreted as few body systems made of an increasing number of {rho}(770) particles. The fixed center approximation of the Faddeev equations is used in order to write the multi-body interaction in terms of the elementary two-body scattering amplitudes. Very good agreement with the experimental masses is found. An extension of the model to include also the interaction with K*(895) is discussed.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Final Report 10. Conference on the Intersections of Particle and Nuclear Physics
The 10th Conference on the Intersections of Particle and Nuclear Physics was held in LaJolla, California on May 26 to May 31, 2009. The Conference Proceedings are published by the American Institute of Physics in Volume 1182 of the AIP Conference Proceedings (ISBN: 978-0-7354-0723-7). The Proceedings include papers from each of the Conference Presenters and a detailed schedule of talks at the Conference. The Table of Contents of the Conference Proceedings is available at http://scitation.aip.org/content/aip/proceeding/aipcp/1182. Support by the U.S. Department of Energy and by DOE Laboratories was essential to the success of the Conference.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
On Lagrangian formulations for arbitrary bosonic HS fields on Minkowski backgrounds
We review the details of unconstrained Lagrangian formulations for Bose particles propagated on an arbitrary dimensional flat space-time and described by the unitary irreducible integer higher-spin representations of the Poincare group subject to Young tableaux Y(s{sub 1},..., s{sub k} ) with k rows. The procedure is based on the construction of scalar auxiliary oscillator realizations for the symplectic sp(2k) algebra which encodes the second-class operator constraints subsystem in the HS symmetry algebra. Application of an universal BRST approach reproduces gauge-invariant Lagrangians with reducible gauge symmetries describing the free dynamics of both massless and massive bosonic fields of any spin with appropriate number of auxiliary fields.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Study of interaction of laser radiation with scattering liquid media under conditions of a varying size distribution function of suspended particles
We report a study of laser radiation transfer processes in scattering media with a time-varying particle size distribution function. We consider the cases of a one-component solution, when the crystal growth occurs during freezing, and a solution with the addition of particles with a time-constant size. The results of the experimental validation of the developed mathematical model are presented. The possibility of using the obtained results to experimentally determine the concentration of metal particles in scattering liquids is considered. (light scattering)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
HZETRN: neutron and proton production in quasi-elastic scattering of GCR heavy-ions
The development of transport models for radiation shielding design and evaluation has provided a series of deterministic computer codes that describe galactic cosmic radiation (GCR), solar particle events, and experimental beams at particle accelerators. These codes continue to be modified to accommodate new theory and improvements to the particle interaction database (Cucinotta et al., 1994, NASA Technical Paper 3472, US Government Printing Office, Washington DC). The solution employed by the heavy-ion transport code HZETRN was derived with the assumption that nuclear fragments are emitted with the same velocity as the incident ion through velocity conserving nuclear interactions. This paper presents a version of the HZETRN transport code that provides a more realistic distribution of the energy of protons and neutrons emitted from GCR interactions in shields. This study shows that the expected GCR dose equivalent is lower than previously calculated for water shields that are less than 110 g cm-2 thick. Calculations of neutron energy spectra in low Earth orbit indicate substantial contributions from relativistic neutrons. c2001 Elsevier Science Ltd. All rights reseved.
NASA Center LaRC↗