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Neutral current pi0 production in MiniBooNE

Description: This paper describes the analysis used to determine the neutral current {pi}{sup 0} production in MiniBooNE in bins of momentum. Additionally, a measurement of the relative coherent production of {pi}{sup 0}s is discussed. The coherent production rate is found to be (19.5 {+-}1.1 (stat) {+-}2.5 (sys))% of the total exclusive neutral current {pi}{sup 0} production rate.
Date: September 1, 2007
Creator: Link, J.M. & Tech., /Virginia
Partner: UNT Libraries Government Documents Department

Observation of pi+pi-pi+pi- photoproduction in ultraperipheral heavy-ion collisions at sqrt sNN = 200 GeV at the STAR detector

Description: We present a measurement of {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} photonuclear production in ultra-peripheral Au-Au collisions at {radical}s{sub NN} = 200 GeV from the STAR experiment. The {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} final states are observed at low transverse momentum and are accompanied by mutual nuclear excitation of the beam particles. The strong enhancement of the production cross section at low transverse momentum is consistent with coherent photoproduction. The {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} invariant mass spectrum of the coherent events exhibits a broad peak around 1540 {+-} 40 MeV/c{sup 2} with a width of 570 {+-} 60 MeV/c{sup 2}, in agreement with the photoproduction data for the {rho}{sup 0}(1700). We do not observe a corresponding peak in the {pi}{sup +}{pi}{sup -} final state and measure an upper limit for the ratio of the branching fractions of the {rho}{sup 0}(1700) to {pi}{sup +}{pi}{sup -} and {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} of 2.5% at 90% confidence level. The ratio of {rho}{sup 0}(1700) and {rho}{sup 0}(770) coherent production cross sections is measured to be 13.4 {+-} 0.8{sub stat.} {+-} 4.4{sub syst.}%.
Date: July 5, 2010
Creator: Collaboration, STAR & Abelev, Betty
Partner: UNT Libraries Government Documents Department

Reply to Comment on"Coherent rho0 photoproduction in bulk matter at high energies"

Description: In their interesting comment on 'Coherent {rho}0 photoproduction in bulk matter at high energies', Rogers and Strikman point out that, at high energies, q{bar q} dipoles with small separations (d) become more important, and that most of the growth of the cross-section is 'driven by the increasingly large contributions from small size (high mass) configurations'; at photon energies of 10{sup 20} eV, over half of the total cross-section is due to dipoles smaller than 0.25 fm. They state that charm production will increase, and may be as much as 30% of the cross-section. The coherent photoproduction of heavier states requires higher energies than coherent {rho} photoproduction, because the formation length scales as 1/M{sup 2}. For the J/{psi}, the required photon energy is 14 times higher than for the {rho}. We agree that higher-mass states become important at higher energies. However, at this point, additional factors come into play; as we note after Eq. (7), our calculation is only properly normalized when the conversion probability is relatively small. At the energies where coherent production of high mass states is possible, the coherent {rho} production probability is large, and it is necessary to consider reverse reactions such as vector meson 'back-propagation' into real photons. The diagonal transitions found in generalized vector meson dominance, such as from a {rho} to a {phi} or J/{psi} may also become important, and a recursive technique appears needed to solve the problem. To the extent that the higher mass states limit the growth of the low-mass cross-section, coherent {rho} photoproduction will be smaller than we calculated. However, the high-mass fractions quoted by Rogers and Strikman are considerably smaller than the fractional difference between the two hadronic models we considered: the Glauber model and the ERR calculations. The presence of higher mass states in our Glauber calculation would ...
Date: January 27, 2010
Creator: Couderc, E. & Klein, S.
Partner: UNT Libraries Government Documents Department

Color coherence in W + jet events

Description: We report on preliminary studies of color coherence effects in p{anti p} collisions, based on data collected by the D0 detector during the 1994-1995 run of the Fermilab Tevatron collider, at a center of mass energy {radical}s = 1.8 TeV. Color interference effects are studied by examining particle distribution patterns in W + Jet events. The data are compared to Monte Carlo simulations with different color coherence implementations and to a recent analytic Modified-Leading-Log perturbative calculation based on the Local Parton-Hadron Duality hypothesis. Soft particle radiation is enhanced in the event plane relative to the transverse plane, in agreement with calculations in which the effects of color coherence are fully included.
Date: November 1, 1997
Creator: Abbott, B.
Partner: UNT Libraries Government Documents Department

Coherent production of {epsilon}{sup +} particles in crystal using proton beam from SSC

Description: The unique possibilities of the SSC can be ideally used for a new generation of coherent generation experiments with relativistic protons which require 20 Tev energy of the incident beam. The availability of 20 Tev proton beam at SSC allows new experiments on coherent production of {var_epsilon}{sup +} particle by relativistic proton in crystal. Experiment carried out at low energies can now be extended with protons in very narrow energy region (resonance energy, which easy can be calculated) using the new accelerator facilities at SSC. We propose to study coherent production via the Coulomb field of the cristal atoms to excite the transition p + {gamma}{implies} {var_epsilon} {sup +} (1189).
Date: May 1, 1995
Creator: Okorokov, V.V. & Dubin, A.Yu.
Partner: UNT Libraries Government Documents Department

Inelastic Cross Sections for Proton - Nucleus Collisions at 205-GeV/c in Nuclear Emulsion

Description: A stack of the nuclear emulsion was exposed to the 205 GeV/c proton beam at NAL. By along-the-track scanning of 1060 m, 2963 inelastic proton-nucleus collisions are obtained. The cross section for the inelastic interaction, its mass number dependence and the cross section for the coherent production are studied.
Date: January 1, 1975
Creator: Konishi, S.; Kusumoto, O.; Okabe, H.; Ozaki, S.; Teranaka, M.; U., /Osaka City et al.
Partner: UNT Libraries Government Documents Department

First Observation of Coherent pi0 Production in Neutrino Nucleus Interactions with E(nu) < 2-GeV

Description: The MiniBooNE experiment at Fermilab has amassed the largest sample to date of {pi}{sup 0}s produced in neutral current (NC) neutrino-nucleus interactions at low energy. This paper reports a measurement of the momentum distribution of {pi}{sup 0}s produced in mineral oil (CH{sub 2}) and the first observation of coherent {pi}{sup 0} production below 2 GeV. In the forward direction, the yield of events observed above the expectation for resonant production is attributed primarily to coherent production off carbon, but may also include a small contribution from diffractive production on hydrogen. Integrated over the MiniBooNE neutrino flux, the sum of the NC coherent and diffractive modes is found to be (19.5 {+-} 1.1 (stat) {+-} 2.5 (sys))% of all exclusive NC {pi}{sup 0} production at MiniBooNE. These measurements are of immediate utility because they quantify an important background to MiniBooNE's search for {nu}{sub {mu}} {yields} {nu}{sub e} oscillations.
Date: March 1, 2008
Creator: Aguilar-Arevalo, A.A.; U., /Columbia; Anderson, C.E.; U., /Yale; Bazarko, A.O.; U., /Princeton et al.
Partner: UNT Libraries Government Documents Department

Antineutrino Interactions in the 14' H(2)-Neon BC

Description: We propose a 50-100,000 photo exploratory exposure of the 14{prime} BC filled with {approx}30% Neon, 70% H{sub 2}, to a broad band {bar {nu}} beam produced by whatever intensity ({approx}&gt; 10{sup 12}) IP/pulse and energy ({approx}&gt; 200 GeV) external proton beam is initially available. The Ne-H{sub 2} mixture permits {approx}10 x higher event rate than pure H{sub 2}; also direct detection of {gamma}, K{sub 2}{sup o}, n; better {mu}{sup {+-}}, e{sup {+-}} identification and the possibility of coherent production reactions from the nucleus as a whole as well as incoherent reactions from both neutrons and protons. The event rate vs. E{sub {bar {nu}}} and q{sup 2} will be measured to {approx}130 GeV permitting (in comparison with HBC experiments) estimate of the A dependence of {sigma}{sub T}, and (given crude flux estimates) tests of scaling and locality in d{sup 2}{sigma}/dE{sub {bar {nu}}}dq{sup 2} and {sigma}{sub T} as well as comparison of {sigma}{sub T} on n and p and of these with corresponding {nu} cross sections. Cross sections, particle momenta, invariant mass and angular correlation spectra will be measured for dominant channels permitting crude tests of {Delta}I = 1, {Delta}I = 1/2, {Delta}S = {Delta}Q, {Delta}S {ne} 2 rules. New particles and phenomena will be searched for.
Date: May 8, 1972
Creator: Bingham, H.H.; Fretter, W.B.; Yost, G.; California, /University of; Bastien, P.; Kirkpatrick, L. et al.
Partner: UNT Libraries Government Documents Department

Four Momentum Transfer Discrepancy in the Charged Current pi+ Production in the MiniBooNE: Data versus Theory

Description: The MiniBooNE experiment has collected what is currently the world's largest sample of {nu}{sub {mu}} charged current single charged pion (CCl{pi}{sup +}) interactions, roughly 46,000 events. The purity of the CCl{pi}{sup +} sample is 87% making this the purest event sample observed in the MiniBooNE detector. The average energy of neutrinos producing CC{pi}{sup +} interactions in MiniBooNE is about 1 GeV, therefore the study of these events can provide insight into both resonant and coherent pion production processes. In this talk, we will discuss the long-standing discrepancy in four-momentum transfer observed between CC{pi}{sup +} data and existing predictions. Several attempts to address this problem will be presented. Specifically, the Rein-Sehgal model has been extended to include muon mass terms for both resonant and coherent production. Using calculations from, an updated form for the vector form factor has also been adopted. The results of this improved description of CC{pi}{sup +} production will be compared to the high statistics MiniBooNE CC{pi}{sup +} data and several existing parametrizations of the axial vector form factor.
Date: September 1, 2009
Creator: Nowak, Jaroslaw A. & U., /Louisiana State
Partner: UNT Libraries Government Documents Department

New Results on Exclusive Production From Nuclei

Description: Three new experiments concerning coherent production from nuclei are discussed. Evidence is presented from the Carnegie Mellon-Illinois-Northwestern-Rochester collaboration regarding coherent production of A{sub 2} mesons in collisions of 23 GeV/c {pi}{sup -} with nuclear targets (C, Al, Cu, Ag). The coherent A{sub 2} cross section which vanishes in the forward direction is typically {approx} 2% that of the A{sub 1}. A neutron dissociation experiment conducted at BNL (Rochester-BNL collaboration) has studied the process n {yields} p{pi}{sup -} occurring coherently on nuclei. Using the optical model of Kolbig-Margolis a 30-40 mb cross section was extracted for the scattering of low-mass p{pi}{sup -} systems on nucleons for momenta of {approx} 13 GeV/c. A similar experiment conducted at FERMILAB (FNAL, University of Massachusetts, Northwestern, Rochester Collaboration) has indicated that at high energies ({approx} 200 GeV/c) Coulomb excitation of the neutron accounts for the major part of the reaction n + Pb {yields} (p{pi}{sup -}) + Pb. While p{pi}{sup -} production on C is dominated through Pomeranchukon exchange.
Date: January 1, 1974
Creator: Ferbel, T. & U., /Rochester
Partner: UNT Libraries Government Documents Department

A proposal to study inelastic diffractive processes by observing coherent production of multipion final states from He nuclei

Description: We propose to study the diffraction dissociation of pions into multi-pion final states, by obtaining the missing mass spectra from the reaction: {pi}{sup -} + He {yields} n{pi}{sup -} + (n - 1){pi}{sup +} + He. The missing mass is calculated from a measurement of the he recoil which is observed in a streamer chamber. In this first exploratory experiment we propose to count the outgoing fast particles, and to measure in a very crude fashion their momenta.
Date: July 1, 1970
Creator: Bastien, P.L.; Cook, V.; Kenyon, R.; Kirkpatrick, L.D.; Lubatti, H.J.; Wolfe, D. et al.
Partner: UNT Libraries Government Documents Department

Coherent Production of Charged Particles on Nuclei by 400-GeV/c Protons

Description: Topological cross sections {delta}{sub coh}{sup (n)} (n = 1,3,5 and 7) of coherent diffractive dissociation of 400 Gev/c protons on nuclei of photoemulsion elements have been measured. Topological cross sections increase in the energy range from 20 to 400 Gev/c. This growth is the most noticeable for multiprong topologies. The total cross section of diffractive coherent production also increases from 8 to 25 mb/nucleus in this energy range. The increasing of the average multiplicity of charged particles in reaction of coherent proton dissociates is consistent with the logarithmic law &lt;n&gt;{sub coh} = (90.25 {+-} 0.05) inp. + (1.3 {+-} 0.25).
Date: January 1, 1977
Creator: Boos, E.G.; Borisenko, A.I.; Kazanskaya, A.N.; Morozova, P.V.; Pavlova, N.P.; Kholmetskaya, A.V. et al.
Partner: UNT Libraries Government Documents Department

Coherent Production of Particles by Protons at 200-GeV/c on Emulsion Nuclei

Description: The coherent diffraction production process is characterized by a very narrow angular distribution of secondary particles that is caused by a small 4-momentum transferred to the nuclei. Besides, they have neither excitation of nuclei, nor disintegration. The quantum numbers of the coherently produced system are the same as those of the incident particle. For proton coherent interactions the number of charged particles must be odd. In this work are presented the data about a cross section for production of three, five and seven charged particles at 200 Gev/c, the energy dependence of these cross sections as angular characteristics of the secondary particles in coherent reactions.
Date: January 1, 1974
Creator: Antonova, M.G.; Boos, E.G.; Goryachikh, A.A.; Chasnikov, I.Ya.; Loktionov, A.A.; Obodova, R. et al.
Partner: UNT Libraries Government Documents Department

Results from a search for a neutral Scalar produced in association with a W boson in p pbar collisions at squareroot s = 1.8 TeV

Description: This paper presents a search for production of a hypothetical heavy particle {ital X} in association with a {ital W} boson. For the search presented here, the kinematics and acceptance are modelled under the assumption that the {ital X} particle has the spin and decay properties of the standard model Higgs boson with the modification that only {ital X} {r_arrow} {ital b}{ital {anti b}} decays are allowed. The {ital W} is required to decay via either the electron or muon mode. The complete D{null} 1992-1995 data set is used. This sample has an integrated luminosity of 100 pb{sup -1} and was taken at a center of mass energy of 1.8 TeV. Limits are placed on the number of associated production events and the production cross section.
Date: August 1, 1996
Creator: Abachi, S.
Partner: UNT Libraries Government Documents Department

Heavy quarkonium production and propagation in nuclei

Description: In the search for the quark-gluon plasma, it has been suggested that the production of charmonium will be suppressed in a quark-gluon plasma because of the screening of the interaction between c and {anti c}. To extract information on the suppression due to the quark-gluon plasma, it is necessary to study the suppression of J/{psi} production by sources different from the quark-gluon plasma. It is therefore useful to examine the mechanism of heavy quarkonium production and its propagation in nuclei. The authors describe a precursor in heavy quarkonium production in terms of a coherent admixture of states of different color, spin, and angular momentum quantum numbers, and obtain the production amplitudes for different quarkonium bound states by projecting out this precursor state onto these bound states. The precursor is absorbed in its passage through a nucleus in a pA reaction, and the total cross section between this precursor with a nucleon can be calculated with the two-gluon model of the Pomeron. Such a description of coherent precursors and their subsequent interactions with nucleons can explain many salient features of J/{psi} and {psi}{prime} production in pA collisions.
Date: December 31, 1997
Creator: Wong, C.Y.
Partner: UNT Libraries Government Documents Department

Thirteen years of pair production

Description: This talk surveys a thirteen-year collaboration with Chris Bottcher on various aspects of strong field electrodynamics. Most of the work centers on the atomic physics associated with the peripheral collisions of ultrarelativistic heavy atoms. The earliest, beginning in about 1979, dealt with the spontaneous emission of positrons from nuclear quasimolecules and touched briefly on the formation of axions as a possible explanation of the anomalous peaks in the spectrum. This work stimulated the extensive studies of particle production from coherent fields that laid the foundations for investigations of nuclear form factors, structure functions, and production mechanisms for the Higgs and other exotic particles. Chris conjectured that the strong fields that are present in these collisions would give rise to nonperturbative effects. Thus, during this time, Chris also worked to develop basis-spline collocation methods for solving dynamical relativistic fermions in super strong fields. This was perhaps one of the best of times for Chris; on these problems alone, he co-authored fifty articles with more than twenty different collaborators.
Date: December 31, 1994
Creator: Strayer, M.R.
Partner: UNT Libraries Government Documents Department

Recent QCD results from the Tevatron

Description: Recent QCD results from the CDF and D0 detectors at the Tevatron proton-antiproton collider are presented. An outlook for future QCD tests at the Tevatron collider is also breifly discussed. 27 refs., 11 figs.
Date: February 1, 1997
Creator: Pickarz, Henryk
Partner: UNT Libraries Government Documents Department

e/sup +/-e/sup -/ hadronic multiplicity distributions

Description: The 29 GeV multiplicity data have been analyzed for e/sup +/ -e/sup -/ ..-->.. hadrons using the partially coherent laser distribution (PCLD). The latter interpolates between the negative binomial and Poisson distributions as the ratio S/N of coherent/incoherent multiplcity varies from zero to infinity. The negative binomial gives an excellent fit for rather large values of the cell parameter k. Equally good fits (for full and partial rapidity range, and for the forward/backward 2 jet correlation) are obtained for the mostly coherent (almost Poissonian) PCLD with small values of k (equal to the number of jets). The reasons for the existence of this tradeoff are explained in detail. The existence of the resulting ambiguity is traced to the insensitivity of the probability distribution to phase information in the hadronic density matrix. The study of higher order correlations (intensity interferometry) among like sign-particles is recommended to resolve this question.
Date: January 1, 1986
Creator: Carruthers, P. & Shih, C.C.
Partner: UNT Libraries Government Documents Department

Coherent pion dissociation into three pions on heavy nuclei

Description: A partial wave decomposition was made of the final state 3 pi system produced in the reaction pi /sup -/+ A yields ( pi /sup -/ pi /sup -/ pi /sup + /) + A at 23 GeV/c and for the elements C, Ai, Cu, and Ag. For low 3 pi masses, the 1/sup +/ state is dominant and its t' distribution shows the expected combination of coherent and incoherent components. The t' distribution of the 2/ sup +/ A/sub 2/ state also requires both coherent and incoherent components. (auth)
Date: March 1, 1974
Creator: Kruse, U.E. & Roberts, T.J.
Partner: UNT Libraries Government Documents Department

Ultrarelativistic atomic collisions

Description: Calculations of the coherent production of free pairs and of pair production with electron capture from ultrarelativistic ion-ion collisions are discussed. Theory and experiment are contrasted, with some conjectures on the possibility of new phenomena. 29 refs., 5 figs., 1 tab.
Date: January 1, 1991
Creator: Bottcher, C. & Strayer, M.R.
Partner: UNT Libraries Government Documents Department

Perspective on relativistic nuclear collisions

Description: The importance of experiments detecting more than one particle is pointed out. The production of nuclei far from stability in peripheral collisions and the expectations for the explosive disassembly of dense nuclear matter (nuclear fireball) and some evidence for it are related. Pion interferometry concerns the measurement of correlations in the momentum and energy of two identical pions; the subject is discussed in relation to incoherent production, coherent production, partially coherent production, final-state interactions, impact parameter average, and outlook. Much of the paper deals with an assessment of the possibility of determining the form of the hadronic spectrum in the high-mass region through nuclear collisions at ultrarelativistic energies. The subject is developed under the following topics: perspective, the initial fireball, isoergic equilibrium expansion of the fireball, quasi-dynamical expansion, quark matter, and the mass degree of freedom. The quasi-dynamical model obtained indicates that certain parameters, such as the ..pi../N and K/N ratios at high kinetic energy, will survive the collision; therefore, a determination of the asymptotic form of the hadron spectrum probably can be made by studying nuclear collisions at very high energies (10 GeV/nucleon in the center of mass). 16 figures. (RWR)
Date: May 1, 1979
Creator: Glendenning, N.K.
Partner: UNT Libraries Government Documents Department