518 Matching Results

Search Results

Advanced search parameters have been applied.

Resonances in high-energy colliding lepton beams

Description: The search for the correct higher symmetry of decay vertices is discussed. It is noted that something higher than SU(3) is certainly valid and colliding lepton beams can help find what it is. SU(6(/sub W/ and its limitations, L = 1, 2 mesons, and the two-photon processes e/sup +/ + e/sup -/ yields e/sup +/ + e/sup -/ + hadrons, and e/sup -/ + e/sup -/ yields e/sup -/ + e/sup -/ + hadrons are considered. (JFP)
Date: March 13, 1973
Creator: Rosner, J.L.
Partner: UNT Libraries Government Documents Department

How to extract the P{sub 33}(1232) resonance contributions from the amplitudes M{sub 1{sup +}}{sup 3/2},E{sub 1{sup +}}{sup 3/2},S{sub 1{sup +}}{sup 3/2} of pion electroproduction on nucleons

Description: Within the dispersion relation approach, solutions of integral equations for the multipoles M{sub 1{sup +}}{sup 3/2},E{sub 1{sup +}}{sup 3/2},S{sub 1{sup +}}{sup 3/2} are found at 0 < Q{sup 2} < 3 GeV{sup 2}. These solutions should be used as input for the resonance and nonresonance contributions in the analyses of pion electroproduction data in the P{sub 33}(1232) resonance region. It is shown that the traditional identification of the amplitude M{sub 1{sup +}}{sup 3/2} (as well of the amplitudes E{sub 1{sup +}}{sup 3/2},S{sub 1{sup +}}{sup 3/2}) with the P{sub 33}(1232) resonance contribution is not right; there is a contribution in these amplitudes which has a nonresonance nature and is produced by rescattering effects in the diagrams corresponding to the nucleon and pion poles. This contribution is reproduced by the dispersion relations. Taking into account nonresonance contributions in the amplitudes M{sub 1{sup +}}{sup 3/2},E{sub 1{sup +}}{sup 3/2}, the helicity amplitudes A{sub p}{sup 1/2}, A{sub p}{sup 3/2} and the ratio E2/M1 for the {gamma}N {r_arrow} P{sub 33}(1232) transition are extracted from experiment at Q{sup 2}=0. They are in good agreement with quark model predictions.
Date: August 1997
Creator: Aznauryan, I. G.
Partner: UNT Libraries Government Documents Department

Including resonances in the multiperipheral model

Description: A simple generalization of the multiperipheral model (MPM) and the Mueller--Regge Model (MRM) is given which has improved phenomenological capabilities by explicitly incorporating resonance phenomena, and still is simple enough to be an important theoretical laboratory. The model is discussed both with and without charge. In addition, the one channel, two channel, three channel and N channel cases are explicitly treated. Particular attention is paid to the constraints of charge conservation and positivity in the MRM. The recently proven equivalence between the MRM and MPM is extended to this model, and is used extensively. (auth)
Date: October 1, 1973
Creator: Pinsky, S.S.; Snider, D.R. & Thomas, G.H.
Partner: UNT Libraries Government Documents Department

W`, Z`, leptoquarks and bump hunting at the Tevatron

Description: This paper summarizes recent results on non-SUSY searches at the Fermilab Tevatron p{bar p} collider. All the analysis are based on the complete data samples recorded by both the CDF and D0 collaborations during the 1992-1995 running period (Run 1), and correspond to {approx} 100 pb{sup -1}. Searches for new neutral heavy vector bosons, leptoquarks, dijet mass resonances, and associated production of new heavy scalars together with vector bosons show no evidence for new physics. Consequently, the results have been interpreted in terms of 95% confidence level limits on production cross sections and new particle masses.
Date: May 1, 1997
Creator: Valls, J.A. & Collaboration, The CDF and DO
Partner: UNT Libraries Government Documents Department

Searches for large extra dimensions and technicolor at the Tevatron

Description: The authors presents the status of searches for large extra spacetime dimensions and technicolor at the Fermilab Tevatron. The author emphasizes recent D0 limits on graviton-mediated exchange processes, and CDF searches for new b{anti b} resonances and third-generation leptoquarks.
Date: August 1, 2000
Creator: Gerdes, David
Partner: UNT Libraries Government Documents Department

The P{sub 33}(1232) resonance contribution into the amplitudes M{sub 1+}{sup 3/2}, E{sub 1+}{sup 3/2}, S{sub 1+}{sup 3/2} from an analysis of the p(e,e{prime}p){pi}{sup 0} data at Q{sup 2} = 2.8, 3.2, and 4 (GeV/c){sup 2} within dispersion relation approach

Description: Within the fixed-t dispersion relation approach the authors have analyzed the TJNAF and DESY data on the exclusive p(e,e{prime}p){pi}{sup 0} reaction in order to find the P{sub 33}(1232) resonance contribution into the multipole amplitudes M{sup 1+}{sup 3/2}, E{sub 1+}{sup 3/2}, S{sub 1+}{sup 3/2}. As an input for the resonance and nonresonance contributions into these amplitudes the earlier obtained solutions of the integral equations which follow from dispersion relations are used. The obtained values of the ratio E2/M1 for the {gamma}{sup *}N {r_arrow} P{sub 33}(1232) transition are: 0.039{+-} 0.029, 0.121{+-} 0.032, 0.04 {+-} 0.031 for Q{sup 2}= 2.8, 3.2, and 4 (GeV/c){sup 2}, respectively. The comparison with the data at low Q{sup 2} shows that there is no evidence for the presence of the visible pQCD contribution into the transition {gamma}N {r_arrow} P{sub 33}(1232) at Q{sup 2}=3--4 GeV{sup 2}. The ratio S{sub 1+}{sup 3/2} / M{sub 1+}{sup 3/2} for the resonance parts of multipoles is: {minus}0.049 {+-} 0.029, {minus}0.099 {+-} 0.041, {minus}0.085 {+-} 0.021 for Q{sup 2}= 2.8, 3.2, and 4 (GeV/c){sup 2}, respectively. The results for the transverse form factor G{sub T}(Q{sup 2}) of the {gamma}{sup *}N {r_arrow} P{sub 33}(1232) transition are lower than the values obtained from the inclusive data. With increasing Q{sup 2}, Q{sup 4}G{sub T}(Q{sup 2}) decreases, so there is no evidence for the presence of the pQCD contribution here too.
Date: August 1, 1998
Creator: I.G.Aznauryan & Stepanyan, S.G.
Partner: UNT Libraries Government Documents Department

Resonance decay effects on anisotropy parameters

Description: We present the elliptic flow v{sub 2} of pions produced from resonance decays. The transverse momentum p{sub T} spectra of the parent particles are taken from thermal model fits and their v{sub 2} are fit under the assumption that they follow a number-of-constituent-quark (NCQ) scaling law expected from quark-coalescence models. The v{sub 2} of pions from resonance particle decays is found to be similar to the measured pion v{sub 2}. We also propose the measurement of electron v{sub 2} as a means to extract open-charm v{sub 2} and investigate whether a thermalized system of quasi-free quarks and gluons (a quark-gluon plasma) is created in collisions of Au nuclei at RHIC.
Date: March 11, 2004
Creator: Dong, Xin; Esumi, S.; Sorensen, P.; Xu, Nu & Xu, Z.
Partner: UNT Libraries Government Documents Department

Proposal for the systematic naming of mesons and baryons

Description: Twenty years ago, the Particle Data Group adopted a systematic naming convention for baryons: the symbols N, ..delta.., ..lambda.., ..sigma.., ..xi.., and ..cap omega.. were to identify the isospin and strangeness, The mesons, by contrast, have become an alphabet soup of uninformative names - theta, iota, xi, zeta, g/sub T/, g/sub s/, H, E, delta, h, g, r, kappa, etc. -, and in some cases identical names are used for mesons with different quantum numbers (A, B, and D). Furthermore, experimentalists are now discovering baryons that contain heavy quarks. It is therefore timely to consider systematic naming conventions both for mesons and for baryons with heavy quarks. The Particle Data Group is circulating this proposal in the hope of generating feedback, and we attach a sheet for responses. It should be emphasized that the Particle Tables would show both the old and new names for some time.
Date: October 1, 1984
Creator: Porter, F.C.; Hernandez, J.J.; Montanet, L.; Roos, M.; Toernqvist, N.A.; Barnett, R.M. et al.
Partner: UNT Libraries Government Documents Department

Two-photon physics. Physics Publication No. 83-175

Description: A brief overview of {gamma}{gamma} physics is presented. Two-body final states are considered and a preliminary result on non-resonant {gamma}{gamma}{r_arrow}h{sup {minus}}h{sup +} (h = {pi}, K, p) is given. The most recent results on the {eta}{prime}, f{sup o}, A{sub 2}, and f{prime} resonances are tabulated and the status of {gamma}{gamma}{r_arrow}{rho}{sub o}{rho}{sup o} is discussed. The measurements of F{sub 2} and high p{sub {perpendicular}} jets are summarized.
Date: October 1, 1982
Creator: Polvado, R. O.
Partner: UNT Libraries Government Documents Department

K-matrix fits to $pi$N $Yields$ N$pi$ and N$pi$$pi$ in the resonance region $Root$s = 1.3 to 2.0 GeV

Description: Thesis. Starting with partial wave amplitudes for pi N yields N pi and pi N yields several isobar model states of N pi pi , one can apply the constraint of unitarity (using the K-matrix). This permits the removal of the overall phase ambiguity of the isobar amplitudes at each energy. The K-matrix fits generated a smooth prescription for the T-matrix amplitudes, enabling one to search the complex energy plane for poles. The uniqueness of these poles was demonstrated by doing Breit-Wigner refits to the fitted T-matrix amplitudes. The success of the results and the obvious interpretation justified a simple determination of coupling signs for which there can be checks with theory. This thesis corresponds closely to a forthcoming paper submitted to Physical Review except that here the K-matrix is based on a 1972 solution A'' isobar-model fits to N pi pi data, and in the final paper solution B'' is used. (auth)
Date: October 1, 1973
Creator: Longacre, R.S.
Partner: UNT Libraries Government Documents Department

Consequences of unitarity and analyticity for weak interactions

Description: One considers the implications of the fact that weak two body scattering amplitudes, when calculated to all orders in any renormalizable model, should exhibit unitary, analytic, ''Mandelstam'' behavior. One discusses from this point of view, the existence of neutral currents, the suppression of $nu$/sub $mu$/e elastic scattering, and the possibility of lepton hadron resonances. A brief review is given of the predictions for lepton--lepton scattering of two models in which Mandelstam behavior is explicitly realized. (auth)
Date: January 1975
Creator: Dicus, D. A. & Teplitz, V. L.
Partner: UNT Libraries Government Documents Department

Bound state of heavy quarks and antiquarks. [Review]

Description: Properties of the charmonium and upsilon families of heavy mesons are reviewed within the framework of quarkonium quantum mechanics. The implications of current data are analyzed and projections are made for heavier quarkonium families. 72 references.
Date: September 1, 1979
Creator: Quigg, C.
Partner: UNT Libraries Government Documents Department

Current status on narrow N anti N states

Description: An attempt is made to summarize the experimental status of narrow B anti B states as of mid-1979. In particular, concentration is placed on the current experimental situations and prospects regarding three serious contenders for the so-called baryonium states. Theoretical concepts of baryoniums, narrow N anti N states known as S(1935), anti pp(2020), and anti pp(2204), and some forthcoming results, and problems of the above three resonances are discussed. 31 references. (JFP)
Date: September 1, 1979
Creator: Chung, S.U.
Partner: UNT Libraries Government Documents Department