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Process Dependent Sivers Function and Implication for Single Spin Asymmetry in Inclusive Hadron Production

Description: We study the single transverse spin asymmetries in the single inclusive particle production within the framework of the generalized parton model (GPM). By carefully analyzing the initial- and final-state interactions, we include the process-dependence of the Sivers functions into the GPM formalism. The modified GPM formalism has a close connection with the collinear twist-3 approach. Within the new formalism, we make predictions for inclusive {pi}{sup 0} and direct photon productions at RHIC energies. We find the predictions are opposite to those in the conventional GPM approach.
Date: January 1, 2011
Creator: Leonard Gamberg, Zhong-Bo Kang
Partner: UNT Libraries Government Documents Department

MOLECULAR RESONANCES AND THE PRODUCTION OF FAST auPARTICLES IN THE REACTION OF 160 WITH 12,13C NUCLEI

Description: A search was made for a resonant, final-state interaction between carbon ions produced in the reactions {sup 12}C + {sup 16}O {yields} a + {sup 12}C + {sup 12}C and {sup 13}C + {sup 16}O {yields} {alpha} + {sup 12}C + {sup 13}C at E{sub lab} = 140 MeV. However, the {alpha}-{sup 12}C coincidence spectra for both {sup 12}C and {sup 13}C targets were instead found to be dominated by the excitation and subsequent {alpha} decay of states in the projectile.
Date: June 1, 1980
Creator: Rae, W.D.; Stokstad, R.G.; Harvey, B.G.; Dacal, A.; LeGrain, R.; Mahoney, J. et al.
Partner: UNT Libraries Government Documents Department

Heavy Quarkonium Production in Single Transverse Polarized HighEnergy Scattering

Description: We formulate the single transverse spin asymmetry in heavyquarkoniumproduction in lepton-nucleon and nucleon-nucleon collisionsinthe non-relativistic limit. We findthat the asymmetry is very sensitiveto the production mechanism. The finalstate interactions with the heavyquark and antiquark cancel out among themselves whenthe pair are producedin a color-single configuration, or cancel out with the initialstateinteraction in pp scattering when they are in color-octet. As aconsequence, the asymmetry is nonzero in ep collisions only in thecolor-octet model, whereas in pp collisions only in the color-singletmodel.
Date: January 17, 2008
Creator: Yuan, Feng
Partner: UNT Libraries Government Documents Department

Inelastic final-state interaction

Description: The final-state interaction in multichannel decay processes is systematically studied with application to B decay in mind. Since the final-state interaction is intrinsically interwoven with the decay interaction in this case, no simple phase theorem like"Watson's theorem" holds for experimentally observed final states. We first examine in detail the two-channel problem as a toy-model to clarify the issues and to remedy common mistakes made in earlier literature. Realistic multichannel problems are too challenging for quantitative analysis. To cope with mathematical complexity, we introduce a method of approximation that is applicable to the case where one prominent inelastic channel dominates over all others. We illustrate this approximation method in the amplitude of the decay B to pi K fed by the intermediate states of a charmed meson pair. Even with our approximation we need more accurate information of strong interactions than we have now. Nonetheless we are able to obtain some insight in the issue and draw useful conclusions on general features on the strong phases.
Date: October 29, 2007
Creator: Suzuki, Mahiko & Suzuki, Mahiko
Partner: UNT Libraries Government Documents Department

Euclidean responses of 4He at high momentum transfer

Description: The Euclidean proton and nucleon responses of <sup>4</sup>He at <I>q</I>=10 fm<sup>-1</sup>, evaluated with the correlated Glauber approximation using a realistic nucleon-nucleon interaction and nonrelativistic kinematics, are compared to those obtained from the Green's function Monte Carlo approach. The results show that final state interactions play a crucial role even at this large value of q, and that their effect can be quantitatively accounted for with the correlated Glauber approximation.
Date: July 1, 1995
Creator: Carlson, Joseph; Benhar, Omar; Schiavilla, Rocco & Pandharipande, Vijay
Partner: UNT Libraries Government Documents Department

Final State Interactions and Relativistic Effects in the Quasielastic (E,E') Reaction

Description: The longitudinal and transverse response functions for the inclusive quasielastic (e,e') reaction are analyzed in detail.A microscopic theoretical framework for the many-body reaction provides a clear conceptual (nonrelativistic) basis for treating final state interactions and goes far beyond simple plane wave or Hermitean potential models.The many-body physics of inelastic final state channels as described by optical and multiple scattering theories is properly included by incorporating a full complex optical potential.Explicit nonrelativistic and relativistic momentum-space calculations quantitatively demonstrate the importance of such a treatment of final state interactions for both the transverse and longitudinal response.Nonrelativistic calculations are performed using final state interactions based on phenomenology, local density models and microscopic multiple scattering theory.Relativistic calculations span a similar range of models and employ Dirac bound state wave f
Date: January 1, 1988
Creator: Picklesimer, Alan; Chinn, Clayton & Van Orden, Jay
Partner: UNT Libraries Government Documents Department

Polarization Transfer in the He-4(polarized-e, e-prime polarized-p)H-3 Reaction up to Q{sup 2}=2.6 (GeV/c){sup 2}

Description: We have measured the proton recoil polarization in the {sup 4}He(polarized-e, e-prime, p){sup 3}H reaction at Q{sup 2} = 0.5, 1.0, 1.6, and 2.6 (GeV/c){sup 2}. The measured ratio of polarization transfer coefficients differs from a fully relativistic calculation, favoring the inclusion of a predicted medium modification of the proton form factors based on a quark-meson coupling model. In contrast, the measured induced polarizations agree reasonably well with the fully relativistic calculation indicating that the treatment of final-state interactions is under control.
Date: November 1, 2002
Creator: Strauch, S.; Dieterich, S.; Aniol, K.A.; Annand, J.R.M.; Baker, O.K.; Bertozzi, W. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the top quark mass at D0

Description: The mass of the top quark is measured using a sample of 93 lepton + 4 or more jets events collected with the D0 detector at the FNAL Tevatron collider. The authors find the top quark mass is 169 {+-} 8(stat.) {+-} 8(syst.) GeV/c{sup 2}. The analysis assumes that top quarks are produced as t{anti t} pairs that decay to W bosons and b quarks. The final states result when one W decays to e{nu} or {mu}{nu} and the other W to q{anti q}. More than four jets may be present because of final and initial state radiation.
Date: December 31, 1996
Creator: Protopopescu, S.
Partner: UNT Libraries Government Documents Department

Lattice determinations of the strange quark mass

Description: The importance of the strange quark mass, as a fundamental parameter of the Standard Model (SM) and as an input to many interesting quantities, has been highlighted in many reviews, eg in Ref [1]. A first principles calculation of m{sub s} is possible in lattice QCD but to date there has been a rather large spread in values from lattice calculations. This review aims to clarify the situation by explaining the particular systematic errors and their effects and illustrating the emerging consensus. In addition, a discussion of the strange quark mass is timely given the recent results from KTeV [2] and NA48 [3] for {epsilon}{prime}/{epsilon} which firmly establish direct CP-violation in the SM and when combined with previous measurements give a world average {epsilon}{prime}/{epsilon} (21:2 {+-} 2:8) x 10{sup {minus}4}. This is in stark disagreement with the theoretical predictions which favor a low {epsilon}{prime}/{epsilon} [4]. Although in principle {epsilon}{prime}/{epsilon} does not depend directly on m{sub s} in practice it has been an input in current phenomenological analyses. This dependence arises because the matrix elements of the gluonic, &lt;Q{sub 6}&gt;{sub 0}, and electroweak, &lt;Q{sub 8}&gt;{sub 2}, penguin operators are of the form &lt;{pi}{pi}{vert_bar}Q{sub i}{vert_bar}K&gt; and final state interactions make them notoriously difficult to calculate directly. They have been, therefore, parameterized in terms of bag parameters, B{sub i}, the strange quark mass, m{sub s} and the top quark mass, m{sub t}, as discussed in detail in Ref. [4]. A recent review of lattice calculations of the matrix elements is in Ref. [5]. In this talk I will focus on some recent and careful lattice determinations of m{sub s}, illustrating the reasons for the large spread in earlier results.
Date: August 25, 1999
Creator: Ryan, Sinead
Partner: UNT Libraries Government Documents Department

Proton Knock-Out in Hall A

Description: Proton knock-out is studied in a broad program in Hall A at Jefferson Lab. The first experiment performed in Hall A studied the {sup 16}O(e,e'p) reaction. Since then proton knock-out experiments have studied a variety of aspects of that reaction, from single-nucleon properties to its mechanism, such as final-state interactions and two-body currents, in nuclei from {sup 2}H to {sup 16}O. In this review the results of this program will be summarized and an outlook given of future accomplishments.
Date: June 1, 2002
Creator: Jager, Kees de
Partner: UNT Libraries Government Documents Department

Tensor Analyzing Powers for Quasi-Elastic Electron Scattering from Deuterium

Description: We report on a first measurement of tensor analyzing powers in quasi-elastic electron-deuteron scattering at an average three-momentum transfer of 1.7 fm{sup -1}. Data sensitive to the spin-dependent nucleon density in the deuteron were obtained for missing momenta up to 150 MeV/c with a tensor polarized {sup 2}H target internal to an electron storage ring. The data are well described by a calculation that includes the effects of final-state interaction, meson-exchange and isobar currents, and leading-order relativistic contributions.
Date: January 1, 1999
Creator: Zhou, Z.-L.; Bouwhuis, M.; Ferro-Luzzi, M.; Passchier, E.; Alarcon, R.; Anghinolfi, M. et al.
Partner: UNT Libraries Government Documents Department

Spacelike and timelike response of confined relativistic particles.

Description: Basic theoretical issues relating to the response of confined relativistic particles are considered including the scaling of t h e response in spacelike and timelike regions of momentum transfer and the role of final state interactions. A simple single particle potential model incorporating relativity and linear confinement is solved exactly and its response is calculated. The response is studied in common approximation schemes and it is found that final state interactions effects persist in the limit that the three-momentum transferred to the target is large. The fact that the particles are bound leads to a non-zero response in the timelike region of four-momentum transfer equal to about 10% of the total strength. The strength in the timelike region must be taken into account to fulfill the particle number sum rule.
Date: January 1, 2002
Creator: Paris, M. W. (Mark W.)
Partner: UNT Libraries Government Documents Department

New baryons in the {Delta}{eta} and {Delta}{omega} channels

Description: The decays of excited nonstrange baryons into the final states {Delta}{eta} and {Delta}{omega} are examined in a relativized quark pair creation model. The wavefunctions and parameters of the model are fixed by previous calculations of N{pi} and N{pi}{pi}, etc., decays through various quasi-two body channels including N{eta} and N{omega}. The results show that the combination of thresholds just below the region of interest and the isospin selectivity of these channels should allow the discovery of several new baryons in such experiments.
Date: July 1, 1998
Creator: Capstick, Simon & Roberts, W.
Partner: UNT Libraries Government Documents Department

Unfactorized versus factorized calculations for {sup 2}H(e,e{prime}p) reactions at GeV energies

Description: In the literature, one often finds calculations of (e,e{prime}p) reactions at GeV energies using the factorization approach. Factorization implies that the differential cross section can be written as the product of an off-shell electron-proton cross section and a distorted missing momentum distribution. While this factorization appears in the non-relativistic plane wave impulse approximation, it is broken in a more realistic approach. The main source of factorization breaking are final state interactions. In this paper, sources of factorization breaking are identified and their numerical relevance is examined in the reaction {sup 2}H(e,e{prime}p) for various kinematic settings in the GeV regime. The results imply that factorization should not be used for precision calculations, especially as unfactorized calculations are available.
Date: September 1, 2000
Creator: Jeschonnek, Sabinne
Partner: UNT Libraries Government Documents Department

Final state interaction in heavy hadron decay

Description: I present a critical account of the final-state interaction (FSI) in two-body B decays from viewpoint of the hadron picture. I emphasize that the phase and the magnitude of decay amplitude are related to each other by a dispersion relation. In a model phase of FSI motivated by experiment, I illustrate how much the magnitude of amplitude can deviate from its factorization value by the FSI.
Date: January 17, 2000
Creator: Suzuki, Mahiko
Partner: UNT Libraries Government Documents Department

Measurement of \nu_\mu and \bar\nu_\mu induced neutral current single $\pi^0$ production cross sections on mineral oil at E_\nu~O(1 GeV)

Description: MiniBooNE reports the first absolute cross sections for neutral current single {pi}{sup 0} production on CH{sub 2} induced by neutrino and antineutrino interactions measured from the largest sets of NC {pi}{sup 0} events collected to date. The principal result consists of differential cross sections measured as functions of {pi}{sup 0} momentum and {pi}{sup 0} angle averaged over the neutrino flux at MiniBooNE. We find total cross sections of (4.76 {+-} 0.05{sub stat} {+-} 0.40{sub sys}) x 10{sup -40} cm{sup 2}/nucleon at a mean energy of &lt;E{sub {nu}}&gt; = 808 MeV and (1.48 {+-} 0.05{sub stat} {+-} 0.14{sub sys}) x 10{sup -40} cm{sup 2}/nucleon at a mean energy of &lt;E{sub {nu}}&gt; = 664 MeV for {nu}{sub {mu}} and {bar {nu}}{sub {mu}} induced production, respectively. In addition, we have included measurements of the neutrino and antineutrino total cross sections for incoherent exclusive NC 1{pi}{sup 0} production corrected for the effects of final state interactions to compare to prior results.
Date: November 1, 2009
Creator: Aguilar-Arevalo, A.A.; /Mexico U., ICN; Anderson, C.E.; U., /Yale; Bazarko, A.O.; U., /Princeton et al.
Partner: UNT Libraries Government Documents Department

Branching Fraction Measurement of B0 to D(*)-pi+and B- to D(*)0pi+ and Isospin Analyses of B to D(*)pi Decays

Description: Using 65 million {Upsilon}(4S) {yields} B{bar B} events collected with the BABAR detector at the PEP-II e{sup +}e{sup -} storage ring at the Stanford Linear Accelerator Center, they measure the color-favored branching fractions {Beta}({bar B}{sup 0} {yields} D{sup +}{pi}{sup -}) = (2.63 {+-} 0.05 {+-} 0.22) x 10{sup -3}, {Beta}({bar B}{sup 0} {yields} D*{sup +}{pi}{sup -}) = (2.79 {+-} 0.08 {+-} 0.18) x 10{sup -3}, {Beta}(B{sup -} {yields} D{sup 0}{pi}{sup -}) = (4.90 {+-} 0.07 {+-} 0.23) x 10{sup -3} and {Beta}(B{sup -} {yields} D*{sup 0} {pi}{sup -}) = (5.52 {+-} 0.17 {+-} 0.43) x 10{sup -3}, where the first error is statistical and the second is systematic. With these results and the current world average for the branching fraction for the color-suppressed decay {bar B}{sup 0} {yields} D{sup (*)0}{pi}{sup 0}, the cosines of the strong phase difference {delta} between the I = 1/2 and I = 3/2 isospin amplitudes are determined to be cos{sigma} = 0.860{sub -0.006-0.028}{sup +0.007+0.029} for the {bar B} {yields} D{pi} process and cos{sigma} = 0.917{sub -0.016-0.051}{sup +0.018+0.059} for the {bar B} {yields} D*{pi} process. The results for cos{delta} suggest that final-state interactions are presented in the D{pi} system.
Date: October 17, 2006
Creator: Aubert, B.
Partner: UNT Libraries Government Documents Department

Many-Body Correlation Effects on the Longitudinal Response in the Quasielastic (e, e') Reaction

Description: A study is made of the influence of many-body corrections on the longitudinal response function for the inclusive quasielastic (e, e') reaction. This response function is well known to be suppressed, by about a factor of two, when compared with theoretical predictions based on the concept of single nucleon ejection. This is a characteristic of the data that persists through a wide range of different nuclei and suggests a violation of the Coulomb sum rule. It is here shown how an estimation of the effect of many-body correlations, including a consistent treatment of inelastic final state interactions, can be computed through a relationship to the nuclear optical model. The approximations are such that the Coulomb sum rule in guaranteed to remain satisfied providing the optical potential is hermitian analytic. Calculations of the longitudinal response are carried out within the Fermi Gas Model using phenomenological parameterizations of the nuclear optical potential. The reductions
Date: January 1, 1990
Creator: Van Orden, Jay & Boucher, Patrick
Partner: UNT Libraries Government Documents Department