Isobar channels and nucleon resonances in π + π − electroproduction on protons

Acomprehensive set of differential cross sections for the reaction γ _ν p → π ^? π ⁺ p at the square of the photon 4-momentum in the range 0.2 < Q ² < 0.6 GeV² and the invariant mass of final-state hadrons in the range 1.3 < W < 1.6 GeV was first obtained with the CLAS detector at the Thomas Jefferson Laboratory. An analysis of these data on the basis of the phenomenological model developed by physicists from the Institute of Nuclear Physics at Moscow State University (INP MSU) and Thomas Jefferson Laboratory (INP MSU-Hall B at Jefferson Lab Collaboration) made it possible to determine, for the first time, the contributions of all isobar channels to the differential cross sections in question. The possibility of extracting the Q ² dependences of the electromagnetic form factors for the P ₁₁(1440) and D ₁₃(1520) resonances in a kinematical region that is the most sensitive to the contribution of the meson-baryon cloud to the structure of nucleon resonances is demonstrated.     

About radiative kaon decay K + → π + π 0 γ

With usage of the Low theorem, the general expression for the amplitude of radiative kaon decay K ⁺ → π ⁺ π ⁰ γ is determined. The possible reason of suppression for the branching ratio of kaon decay K ⁺ → π ⁺ π ⁰ is considered. The text was submittedby the authors in English.     

π+p and K+p elastic scattering at 250 GeV/c

Results are presented on π⁺p and K⁺p elastic scattering at 250 GeV/c, the highest momentum so far reached for positive meson beams. The experiment (NA22) was performed with the european hybrid spectrometer. The π⁺p elastic cross section stays constant with energy while the K⁺p cross section increases.     

Elastic and inelastic positron-helium scattering

Elastic and inelastic positron--helium scatterings have been investigated with the coupled-channel optical method (CCO). Ionization continuum and positronium formation channels are included via a complex equivalent-local optical potential. Calculations are reported of cross sections of elastic scattering, total excitation and n=2, 3, and 4 excitations of ground-state helium for incident energies from 30~eV to 400~eV. The present calculation shows that the ionization and Ps-formation channels significantly affect the cross sections of elastic and inelastic positron--helium scatterings.     

A study ofK + p elastic scattering and reactionK + p→K + pπ+π− at 70 GeV/c

Results are presented onK ⁺ p elastic scattering and on the reactionK ⁺ p→K ⁺ pπ⁺π^? at 70 GeV/c. For the elastic channel, we measured the total ((2.29±0.04)mb) and differentialdσ/dt cross sections. The reactionK ⁺ p→K ⁺ pπ⁺π^? has a total cross section of (470±23) μb and is shown to be dominated by diffractive dissociation processes. The contributions of the quasi-two-body channels $$K^ + p \to K*^0 (890)\Delta ^{ + + } (1,236)$$ and $$K^ + p \to K*^0 (1,430)\Delta ^{ + + } (1,236)$$ and of the Double-Pomeron Exchange (DPE) processes are estimated.     

Measurements of π+p,K+p and pp elastic scattering)

The paper presents the results on differential cross sections for elastic scattering of 7⁺-, K⁺-mesons and protons on protons in the 4-momentum transfer squared range 0·08 ¦t¦ 1·0 (GeV/c)² and incident particle momentum of 29 and 43 GeV/c for pions and kaons and 29, 43, 50 and 65 GeV/c for protons. The measurements were taken with the spectrometer Sigma, installed in the positive beam of the IHEP accelerator.Presented by F. A. Yotch at the Symposium on Hadron-Hadron Scattering at High Energies, Liblice, Czechoslovakia, June 16–21, 1975.The authors would like to express their gratitude to A. A.Logunov, Yu. D.Prokoshkin, L. D.Soloviev and V. A.Yarba for their support of this experiment. We are indebted to CERN Administration for giving us a permission to use a part of equipment of the CIBS spectrometer and to W.Kienzle for useful discussions.     

Production of γγ+2 jets from double parton scattering in proton-proton collisions at the LHC

Cross sections for the production of pairs of photons plus two additional jets produced from double parton scattering in high-energy proton-proton collisions at the LHC are calculated for the first time.The estimates are based on the theoretical perturbative QCD predictions for the productions of γγ at next-to-next-to-leading-order,jet+jet and γ+jet at next-to-leading-order,for their corresponding single-scattering cross sections.The cross sections and expected event rates for γγ+2 jets from double parton scattering,after typical acceptance and selections,are given for proton-proton collisions with the collision energy s~(1/2)=13 TeV and integrated luminosity of 100 fb~(-1) planned for the following years,and also s~(1/2)=14 TeV with 3000 fb~(-1) of integrated luminosity as the LHC design.     

D* meson production cross sections in e − p and e + p scattering processes at the HERA collider

The cause of the D* meson production cross sections in e ^? p and e ⁺ p deep inelastic scattering processes in the ZEUS experiment at the HERA collider that are anomalously different is determined.     

High Energy Elastic p and p p Differential Cross Sections

<正>(Updated September 2013.COMPAS group.IHEP,Protvino)Using new results from FNAL-COLLIDER-D0 experiment in pp elastic collisions at s~(1/2)=1.96 TeV[1],CERN-LHC-TOTEM experiment in p p elastic collisions at s~(1/2)=7,8 TeV[2-3]and PAO experiment in proton-air collisions at 57 TeV[4]the amplitudes of the elastic p p and p p collisions are investigated in a most broad region in s~(1/2)and t via three observables da/dt(s,t).σ~(tot)(s),and p(s).The summary of the database for dσ/dt(s,t)is presented in Figure 50.10.where projection of the dσ/dt(s~(1/2),t)to the(da/dt,—t)plane orthogonal to the s~(1/2)axis is displayed.     

Elastic differential cross sections of electron scattering by CF_4 at intermediate energies

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Elastic and inelastic scattering of π mesons on 7Li nuclei

Within the diffraction theory of multiple scattering, the differential cross sections for elastic and inelastic pion scattering on a ⁷Li nucleus are calculated for the case where the final nucleus is either in the ground or in the first excited state. The nuclear wave function is set to that in the αt cluster model. The sensitivity of the calculated observables to variations in the type of the wave functions for the alpha-particle and the triton cluster and for their relative motion is investigated. Various multiplicities of scattering and rescattering on the clusters constituting the ⁷Li nucleus are taken into account, and their contributions to the cross section are revealed. The results of the calculations are compared with experimental data at E _π=143, 164, and 194 MeV.     

Deuteron fragmentationd+p→p+p+n at 9 GeV/c

Gamma-ray energy correlations have been measured for several reactions leading to light-mass Hf isotopes with 160 ?A?166. The correlation spectra show ridge-valley structures up to high rotational frequencies from which a drop in J _c ⁽²⁾ is deduced at high frequencies. This drop suggests that a large portion of the angular momentum is generated by aligning particles. It may also be explained by the theoretically predicted triaxial states with large deformation.     

Same-sign W pair production as a probe of double-parton scattering at the LHC

We study the production of same-sign W boson pairs at the LHC in double parton interactions. Compared with simple factorised double parton distributions (dPDFs), we show that the recently developed dPDFs, GS09, lead to non-trivial kinematic correlations between the W bosons. A numerical study of the prospects for observing this process using same-sign dilepton signatures, including W ^± W ^± jj, diboson and heavy flavour backgrounds, at 14 TeV centre-of-mass energy is then performed. It is shown that a small excess of same-sign dilepton events from double parton scattering over a background dominated by single scattering W ^± Z(γ ^*) production could be observed at the LHC.     

Simulation and analysis of 13N+p elastic resonance scattering

The ^13 N＋p elastic resonance scattering has been studied at the secondary radioactive beam facility of CIAE in inverse kinematics via a thick-target method. The excitation function for the ^13N（p,p） scattering was obtained in the energy interval of Ecru ≈0.5-3.2 MeV with a ^13 N secondary beam of （47.8±1.5） MeV. Careful analysis of the secondary beam components and extensive Monte-Carlo simulations enable the resolution of the experimental proton spectra. The resonance parameters for five low-lying levels in ^14 O were deduced by Rmatrix fitting calculations with MULTI7 and SAMMY-M6-BETA. The present results show general agreement with those from a recent similar work, and thus confirm the observation of a new 0^- level at 5.7 MeV in 140 with an improved width of 400（45） keV.     

Elastic scattering of e∓ by Na atoms

ABSTRACT

The differential, integrated elastic, momentum transfer, viscosity and total cross-sections along with Sherman function for the elastic scattering of electrons and positrons by sodium atoms have been calculated within the framework of complex projectile–atom optical potential model at the impact energies 0.1 ≤ E_i ≤ 10⁴ eV for both the projectiles. The relativistic Dirac partial wave techniques, with accurate analytical charge densities, are used to obtain the scattering amplitudes. The present results produce satisfactory agreement with the experimental measurements and other theoretical calculations available in the literature.     

Associated production of Higgs boson and t at LHC

One of the future goals of the LHC is to precisely measure the properties of the Higgs boson.The associated production of a Higgs boson and top quark pair is a promising process to investigate the related Yukawa interaction and the properties of the Higgs.Compared with the pure scalar sector in the Standard Model,the Higgs sector contains both scalars and pseudoscalars in many new physics models,which makes the ttH interaction more complex and provides a variety of phenomena.To investigate the ttH interaction and the properties of the Higgs,we study the top quark spin correlation observables at the LHC.