π+N→N^*Production in the Quark Model

Abstract

The cross section for the rc+ N-->N* production is calculated m the quark model using the static approximation for quarks. It is assumed that the incident pion is absorbed by a quark in the nucleon, resulting in the excitation of the nucleon. The main results are that the extension of the nucleon wave function is about 2.0"-'3.5 Ge v-1 and that the coupling constant of the pion with the quark is f 2 qqn/4rc"""0.3. The ratio of the cross section of the process passing through the resonance N* to the total cross section is also roughly given. The selection rule for the orbital angular momentum of the incident pion is obtained and agrees well with the experiment. by guest on March 25, 2015 http://ptp.oxfordjournals.org/ Downloaded from 7C + N->N* Production in the Quark Model (/) (N*) ~</h (r1, r2, r3) Xs,us, c/h (r 1 , r 2 , r 3 ) is the space part of N* wave function with total orbital angular momentum L, and r1, r2, rs is the position vector of the three quarks in the nucleon and resonances. Xs,us is the spin-unitary spin part of N* wave function.As the nucleon resonances tabulated in Table I are assumed to belong to the by guest on March 25, 2015 http://ptp.oxfordjournals.org/ Downloaded from

Three-quark force in p–p elastic scattering

“…One of the successful models in the study of proton-proton scattering as composite systems is the multiple scattering theory of Glauber [28]. Using Glauber theory [29][30][31] the authors show that the multiple scattering mechanism with the quark degree of freedom describes the diffraction pattern of particle-particle elastic scattering and quarks having spatial dimensions which are small compared to the corresponding hadrons and a good agreement with the experimental data of high energy was obtained. With simple Gaussian form of proton wave function, by introducing the time-ordering effect in quark-quark multi-scattering the good agreement with the proton-proton data was obtained at CERN-ISR energies [35].…”

New physics from TOTEM’s recent measurements of elastic and total cross sections

“…Fits to pp and pp total cross section data[1,25,26,27,29] using the model Eqs (5)(6)(7)(8)(9)(10)(11)(12)(13)…”

High-Energy Elastic Proton-Proton Scattering

“…In this connection, we note that the dropping of various terms in Ref. 1) has been justified by appealing to Abarbanel's5) qualitative argument that in double scattering they represent processes which would take too much time to occur, and hence should be suppressed at high energies. We find that this is indeed true for the double-scattering term rF>, but it is not true for the triplescattering terms for the values of sand t used in this paper.…”

“…Wakaizumi's pop elastic scattering amplitude (1) contains an empirical term To fitted to the very steep forward peak before the break in dC5/dt at Itl""'0.2 GeV 2 . (Note that a factor (4lr )-1 was accidentally left out of the expression for To in Ref. 1).)…”