22 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Pions"  
Results: 1 - 22
open access

Constraints on rhobar, etabar from B to K*pi

Description: A linear CKM relation, {bar {eta}} = tan {Phi}{sub 3/2}({bar p} - 0.24 {+-} 0.03), involving a 1{sigma} range for {Phi}{sub 3/2}, 20{sup o} < {Phi}{sub 3/2} < 115{sup o}, is obtained from B{sup 0} {yields} K*{pi} amplitudes measured recently in Dalitz plot analyses of B{sup 0} {yields} K{sup +}{pi}{sup -}{pi}{sup 0} and B{sup 0}(t) {yields} K{sub S}{pi}{sup +}{pi}{sup -}. This relation is consistent within the large error on {Phi}{sub 3/2} with other CKM constraints which are unaffected b… more
Date: January 14, 2008
Creator: Gronau, Michael; Pirjol, Dan; Soni, Amarjit & Zupan, Jure
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Observation of B+ to b_1+K0 and Search for B-meson Decays to b_10K0 and b_1pi0

Description: We present the results of searches for decays of B mesons to final states with a b{sub 1} meson and a neutral pion or kaon. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 465 million B{bar B} pairs produced in e{sup +}e{sup -} annihilation. The results for the branching fractions are, in units of 10{sup -6}, {Beta}(B{sup +} {yields} b{sub 1}{sup +}K{sup 0}) = 9.6 {+-} 1.7 {+-} 0.9, {Beta}(B{sup 0} {yields} b{sub 1}{sup 0}K{sup 0}) = 5.1 {+-} 1.8… more
Date: May 14, 2008
Creator: Aubert, B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A Measurement of the Spatial Distribution of Diffuse TeV Gamma Ray Emission from the Galactic Plane with Milagro

Description: Diffuse {gamma}-ray emission produced by the interaction of cosmic-ray particles with matter and radiation in the Galaxy can be used to probe the distribution of cosmic rays and their sources in different regions of the Galaxy. With its large field of view and long observation time, the Milagro Gamma Ray Observatory is an ideal instrument for surveying large regions of the Northern Hemisphere sky and for detecting diffuse {gamma}-ray emission at very high energies. Here, the spatial distributio… more
Date: May 14, 2008
Creator: Abdo, A. A.; Allen, B.; Aune, T.; Berley, D.; Blaufuss, E.; Casanova, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Physical results from 2+1 flavor domain wall QCD

Description: We review recent results for the chiral behavior of meson masses and decay constants and the determination of the light quark masses by the RBC and UKQCD collaborations. We find that one-loop SU(2) chiral perturbation theory represents the behavior of our lattice data better than one-loop SU(3) chiral perturbation theory in both the pion and kaon sectors. The simulations have been performed using the Iwasaki gauge action at two different lattice spacings with the physical spatial volume held ap… more
Date: July 14, 2008
Creator: Scholz,E.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

VHE Gamma-Rays From Westerlund 2 And Implications for the Inferred Energetics

Description: The H.E.S.S. collaboration recently reported the discovery of VHE {gamma}-ray emission coincident with the young stellar cluster Westerlund 2. This system is known to host a population of hot, massive stars, and, most particularly, the WR binary WR 20a. Particle acceleration to TeV energies in Westerlund 2 can be accomplished in several alternative scenarios, therefore we only discuss energetic constraints based on the total available kinetic energy in the system, the actual mass loss rates of … more
Date: November 14, 2007
Creator: Reimer, O.; /Stanford U., HEPL /KIPAC, Menlo Park; Aharonian, F.; /Heidelberg, Max Planck Inst. /Dublin Inst.; Hinton, J.; U., /Leeds et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Examination of Flavor SU(3) in B, Bs to Kpi Decays

Description: We update a discussion of the relation between the weak phase and the rates and CP asymmetries of several K{pi} decays of B{sup +}, B{sup 0}, and B{sub s}. We emphasize the impact of measurements of B{sub s} {yields} K{pi}. Current data indicate large SU(3) breaking in the strong phases or failure of factorization (including its application to penguin amplitudes) in K{pi} modes of B{sup 0} and B{sub s}. SU(3) and factorization only remain approximately valid if the branching ratio for B{sub s} … more
Date: April 14, 2008
Creator: Chiang, Cheng-Wei; /Taiwan, Natl. Central U. /Taiwan, Inst. Phys.; Gronau, Michael; /SLAC; Rosner, Jonathan L. & /Chicago U., EFI /Chicago U.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Comments on the Interaction Between Theory and Experiment in High Energy Physics

Description: This paper discusses work being conducted in High Energy Physics and Nuclear Physics where theory and experiment go hand in hand. Pion capture, proton-antiproton interactions, kaon-pion interactions and hypernuclei decay are discussed as examples. (LSP)
Date: September 14, 1990
Creator: Derrick, M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Estimates of rates and errors for measurements of direct-. gamma. and direct-. gamma. + jet production by polarized protons at RHIC

Description: Studies of inclusive direct-{gamma} production by pp interactions at RHIC energies were performed. Rates and the associated uncertainties on spin-spin observables for this process were computed for the planned PHENIX and STAR detectors at energies between {radical}s = 50 and 500 GeV. Also, rates were computed for direct-{gamma} + jet production for the STAR detector. The goal was to study the gluon spin distribution functions with such measurements. Recommendations concerning the electromagneti… more
Date: August 14, 1992
Creator: Beddo, M. E.; Spinka, H. & Underwood, D. G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

How Many Muons Do We Need to Store in a Ring For Neutrino Cross-Section Measurements?

Description: Analytical estimate of the number of muons that must decay in the straight section of a storage ring to produce a neutrino & anti-neutrino beam of sufficient intensity to facilitate cross-section measurements with a statistical precision of 1%. As we move into the era of precision long-baseline {nu}{sub {mu}} {yields} {nu}{sub e} and {bar {nu}}{sub {mu}} {yields} {bar {nu}}{sub e} measurements there is a growing need to precisely determine the {nu}{sub e} and {bar {nu}}{sub e} cross-sections in… more
Date: July 14, 2011
Creator: Geer, Steve
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Monte Carlo Simulation of Proton-induced Cosimc Ray Cascades in the Atmosphere

Description: We have developed a Monte Carlo model of the Earth's atmosphere and implemented it in three different codes (GEANT4, MCNPX, and FLUKA). Primary protons in the energy range of 1 GeV-100 TeV are injected at the top of the atmosphere. The codes follow the tracks of all relevant secondary particles (neutrons, muons, gammas, electrons, and pions) and tally their fluxes at selectable altitudes. Comparisons with cosmic ray data at sea level show good agreement.
Date: March 14, 2007
Creator: Hagmann, C A; Lange, D J & Wright, D M
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Estimates of rates and errors for measurements of direct-{gamma} and direct-{gamma} + jet production by polarized protons at RHIC

Description: Studies of inclusive direct-{gamma} production by pp interactions at RHIC energies were performed. Rates and the associated uncertainties on spin-spin observables for this process were computed for the planned PHENIX and STAR detectors at energies between {radical}s = 50 and 500 GeV. Also, rates were computed for direct-{gamma} + jet production for the STAR detector. The goal was to study the gluon spin distribution functions with such measurements. Recommendations concerning the electromagneti… more
Date: August 14, 1992
Creator: Beddo, M. E.; Spinka, H. & Underwood, D. G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Measurement of Neutron Energy Spectra behind Shielding of a 120 GeV/c Hadron Facility

Description: Neutron energy spectra were measured behind the lateral shield of the CERF (CERN-EU High Energy Reference Field) facility at CERN with a 120 GeV/c positive hadron beam (mainly a mixture of protons and pions) on a cylindrical copper target (7-cm diameter by 50-cm long). NE213 organic liquid scintillator (12.7-cm diameter by 12.7-cm long) was located at various longitudinal positions behind shields of 80- and 160-cm thick concrete and 40-cm thick iron. Neutron energy spectra in the energy range b… more
Date: December 14, 2005
Creator: Nakao, N.; Rokni, S. H.; Vincke, H.; Khater, Hesham; Prinz, A. A.; Taniguchi, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Observation of CP Violation in B0 to K+pi- and B0 to pi+pi-

Description: The authors report observations of CP violation in the decays B{sup 0} {yields} K{sup +}{pi}{sup -} and B{sup 0} {yields} {pi}{sup +}{pi}{sup -} in a sample of 383 million {Upsilon}(4S) {yields} B{bar B} events. They find 4372 {+-} 82 B{sup 0} {yields} K{sup +}{pi}{sup -} decays and measure the direct Cp-violating charge asymmetry {Alpha}{sub K{pi}} = -0.107 {+-} 0.018(stat){sub -0.004}{sup +0.007}(syst), which excludes the CP-conserving hypothesis with a significance of 5.5 standard deviations… more
Date: March 14, 2007
Creator: Aubert, B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Comment on Form Factor Shape and Extraction of $|V_{ub}|$ from $B\to\pi l \nu$

Description: We point out that current experimental data for partial B {yields} {pi}l{nu} branching fractions reduce the theoretical input required for a precise extraction of |V{sub ub}| to the form-factor normalization at a single value of the pion energy. Different parameterizations of the form factor shape leading to this conclusion are compared and the role of dispersive bounds on heavy-to-light form factors is clarified.
Date: September 14, 2005
Creator: Becher, Thomas & Hill, Richard J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Observation of new resonances decaying to $D\pi$ and $D^*\pi$ in inclusive $e^ e^-$ collisions near $\sqrt{s}

Description: The authors present a study of the D{sup +}{pi}{sup -}, D{sup 0}{pi}{sup +}, and D*{sup +}{pi}{sup -} systems in inclusive e{sup +}e{sup -} {yields} c{bar c} interactions in a search for new excited D meson states. they use a dataset, consisting of {approx} 454 fb{sup -1}, collected at center-of-mass energies near 10.58 GeV by the BABAR detector at the SLAC PEP-II asymmetric-energy collider. They observe, for the first time, candidates for the radial excitations of the D{sup 0}, D*{sup 0}, and … more
Date: September 14, 2010
Creator: del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Particle production for a muon storage ring: I. Targetry and pi/mu yield

Description: Efficient production and collection of a large number of muons is needed to make a neutrino factory based on a muon storage ring viable. Results of extensive MARS simulations are reported for 2 to 30 GeV protons on various targets in a 20 T hybrid solenoid, followed by a matching section and decay channel. Part 1 describes pion and muon yields, targetry issues, and beam energy and power considerations. Part 2 describes radiation loads on targets, the capturing system and shielding.
Date: September 14, 2000
Creator: Mokhov, Nikolai V.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP ON SPIN PHYSICS AT RHIC IN YEAR-1 AND BEYOND.

Description: The much anticipated RHIC spin physics program will commence this fall when the first physics run with colliding beams of polarized protons is expected. More specifically, the planned year-1 RHIC-Spin measurements are (1) the double-spin asymmetry A{sub LL}{sup {pi}} in production of pions by collisions of longitudinally polarized protons (in order to obtain first information on the proton's spin-dependent gluon density, {Delta}g); (2) the transverse single-spin asymmetry A{sub N}{sup {pi}} for… more
Date: May 14, 2001
Creator: Bland, L.; Boer, D.; Saito, N. & Vogelsang, W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The Muon Collider- Status and physics prospects

Description: The current status of the muon collider is presented, with a brief historical review. The proton source and the pion production and decay channel needed for a first muon collider (FMC) are described. A brief review of ionization cooling theory is followed by the current status of cooling ideas. The acceleration scheme and the collider ring are presented, followed by the backgrounds expected in a muon collider detector and the physics potential of such a detector. The physics potential of a muon… more
Date: December 14, 1999
Creator: Raja, Rajendran
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

QCD Factorization for B {r_arrow} {pi}{pi} Decays: Strong Phases and CP Violation in the Heavy Quark Limit

Description: We show that, in the heavy quark limit, the hadronic matrix elements that enter B meson decays into two light mesons can be computed from first principles, including ''non-factorizable'' strong interaction corrections, and expressed in terms of form factors and meson light-cone distribution amplitudes. The conventional factorization result follows in the limit when both power corrections in 1/m{sub b} and radiative corrections in {alpha}{sub s} are neglected. We compute the order-{alpha}{sub s}… more
Date: May 14, 1999
Creator: Neubert, Matthias
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
Back to Top of Screen