Narrow Results

An efficient neural network (NN) has been designed to simulate the hadron–hadron interaction at high energy. Two cases have been considered simultaneously, the proton–proton (p–p) and the pion–proton (π-p) interactions. The neural network has been trained to produce the charged multiplicity distribution for both cases based on samples from the overlapping functions. The trained NN shows a good performance in matching the trained distributions. The NN is then used to predict the distributions that are not present in the training set and matched them effectively. The robustness of the designed NN in the presence of uncertainties, in the overlapping functions has been demonstrated.

The behavior of the hadron scattering amplitude determined by the gravitation interaction of hadron at high energies with impact of the KK-modes in d-brane models of gravity is examined. The possible periodic structure of the scattering amplitude and its dependence from number of the additional dimensions are analyzed. The effects of the gravitational hadron form factors obtained from the hadron generalized parton distributions (GPDs) on the behavior of the interaction potential and the scattering amplitude are also analyzed. It is shown that in most part the periodic structure comes from the approximation of our calculations.

Taking into account the different forms of the Coulomb-hadron interference phase and the possible spin-flip contribution the new analysis of the experimental data of the proton–antiproton elastic scattering at 3.8<p_L<6.0 GeV/c and small momentum transfer is carried out. It is shown that the size of the spin-flip amplitude can be determined from the form of the differential cross-sections at small-t, and the deviation of ρ(s, t) obtained from the examined experimental data of the scattering from the analysis¹, based on the dispersion relations, is conserved in all examined assumptions. The analysis of the proton–proton elastic scattering at 9<p_L<70 GeV/c also shows the impact of the examined effects on the form of the differential cross-sections.

We study the interplay of hadronic and Coulomb interactions for pp scattering at LHC energies on the basis of the previous determination of the real part of the amplitude [V. V. Anisovich, V. A. Nikonov and J. Nyiri, Int. J. Mod. Phys. A30, 1550188 (2015)]. The interference of hadron and Coulomb interactions is discussed in terms of the K-matrix function technique. Supposing the black disk mode for the asymptotic interaction of hadrons, we calculate interference effects for the energies right up to $\sqrt{s}=10^6$ TeV. It turns out that the real part of the amplitude is concentrated in the impact parameter space at the border of the black disk that results in a growth of interplay effects with the energy increase.

The strangeness s=+1 pentaquark states and the six-quark quark clusters qqqqqq are investigated. By analyzing the inherent nodal structure of the systems, the low-lying states are picked out. By comparing the accessibility of the nodeless states and referring the presently obtained K-N interaction potential, we propose that the quantum numbers of the lowest-lying pentaquark state Θ⁺ may be (J^P, T)=(½⁺,0) and L=1. Meanwhile, the possible dibaryon states are briefly discussed.

The HARP experiment at CERN is performing extensive measurements of hadron production cross sections and secondary particle yields in the energy range 1.5-15 GeV over the full solid angle, using a large set of cryogenic and solid targets. The hadron production in this region is a relevant ingredient in several branches of neutrino physics, including the characterization of neutrino beams, precise prediction of atmospheric neutrino fluxes, and quantification of pion production and capture for neutrino factory design. An overall precision of a few percent is required from the experiment to reach the final aim. The experimental layout comprises two spectrometers to perform momentum measurement of the secondaries produced in the target. The track momentum reconstruction in the spectrometers is complemented by a set of particle identification detectors that allow, with some redundancy, the particle type discrimination. Approximately 30 TB of data corresponding to 420 millions of events have been collected. The measurements of hadron production cross sections in the forward region (up to about 250 mrad) are reported using the K2K replica targets and a proton beam of 12.9 GeV/c. This is an appealing physics case given the immediate interest for those experiments and for the neutrino community.

Results of many ψ(2S) hadronic decays and the results of ψ(2S) radiative/hadronic transitions from BES collaboration in the past year are presented. Measurement of and the preliminary result of searching for the decay ψ(3770) → ρπ are also reported.

The new observation of X(1835) is reported using 58 million J/ψ events collected at BES II detector. We also present the measurements of J/ψ and η_c decays, of them some are the first measurements and some improve the precision in previous measurements.

The J-PARC Hadron Facility is designed as a multipurpose experimental facility for a wide range of particle and nuclear physics programs, aiming to provide the world highest intensity secondary beams. The first primary beam has been successfully extracted and transported to the beam dump on January 2009. Currently three secondary beam lines come into operation, and the new beam line will be completed in the early summer of 2010. Various experimental programs are proposed at each beamline and some of them are preparing to start physics run. Most of the experimental researches concerns the studies of hypernuclei and searches for new hadronic states. As the first experiment at the J-PARC Hadron Facility, search for the Θ⁺ pentaquark via pion-induced hadronic reaction will be performed in the autumn of 2010. The current status and recent results of the commissioning for the beam line are reported.

Central production of lepton–antilepton pairs (e⁺e^- and μ⁺μ^-) and heavy quark composite states (charmonia and bottomonia) in diffractive proton collisions (proton momenta transferred |q_⊥| ~ m/ln s) are studied at ultrahigh energies (ln s ≫ 1), where σ_tot(pp^±) ~ ln^N s with 1 ≲ N ≲ 2. The pp^±-rescattering corrections, which are not small, are calculated in terms of the K-matrix approach modified for ultrahigh energies. Two versions of hadron interactions are considered in detail: the growth (i) σ_tot(pp^±) ~ ln² s, σ_inel(pp^±) ~ ln² s within the black disk mode and (ii) σ_tot(pp^±) ~ ln² s, σ_inel(pp^±) ~ ln s within the resonant disk mode. The energy behavior of the diffractive production processes differs strongly for these modes, thus giving a possibility to distinguish between the versions of the ultrahigh energy interactions.

On the basis of requirements of unitarity and analyticity we analyze the real and imaginary parts of the scattering amplitude at recent ultrahigh energies, $\text{1–100}\mathrm{\text{TeV}}$. The predictions for the region $\sqrt{s}>100\mathrm{\text{TeV}}$ and $q^2<0.4{\mathrm{\text{GeV}}}^2$ are given supposing the black disk asymptotic regime. It turns out that the real part of the amplitude is concentrated in the impact parameter space at the border of the black disk.

Comparative analysis of the interplay of hadron and Coulomb interactions in $p{p}^{\pm }$ scattering amplitudes is performed in a broad energy interval, $\sqrt{s}=1\text{–}10^6\mathrm{\text{TeV}}$, for two extreme cases: for the asymptotic interactions of hadrons in black disk and resonant disk modes. The interactions are discussed in terms of the $K$-matrix function technique. In the asymptotic regime, the real part of the hadronic amplitude is concentrated in both cases on the boundary of the disks in the impact parameter space but the LHC energy region is not asymptotic for the resonant disk mode that lead to a specific interplay of hadronic and Coulombic amplitudes. For the $pp$ scattering at $\sqrt{s}\sim 10\mathrm{\text{TeV}}$ an interplay of the hadron and Coulomb interactions in the resonant disk modes is realized in a shoulder in $d{\sigma }_{\mathrm{\text{el}}}/d{q}^2$ at $q^2\sim 0.0025\text{–}0.0075{\mathrm{\text{GeV}}}^2$. The absence of such a shoulder in the data at 8 TeV can be considered as an argument against the resonant disk mode.

We investigate the influence of retardation effects on covariant 3-dimensional wave functions for bound hadrons. Within a quark-(scalar) diquark representation of a baryon, the four-dimensional Bethe–Salpeter equation is solved for a 1-rank separable kernel which simulates Coulombic attraction and confinement. We project the manifestly covariant bound state wave function into three dimensions upon integrating out the non-static energy dependence and compare it with solutions of three-dimensional quasi-potential equations obtained from different kinematical projections on the relative energy variable. We find that for long-range interactions, as characteristic in QCD, retardation effects in bound states are of crucial importance.

J-PARC Hadron Experimental Facility is designed to carry out a variety of particle and nuclear physics experiments with intense secondary particles generated by 750 kW proton beams. The first construction stage including the experimental hall, the primary beam line, and one secondary beam line (K1.8BR) has been completed at the end of December 2008. In order to handle the high intensity primary beam safely, we have developed many special devices working under severe radiation environment. The present article reports the current status of the Hadron Experimental Facility in detail.

J-PARC Hadron Experimental Facility is designed to carry out a variety of particle and nuclear physics experiments with intense secondary particles generated by 750 kW proton beams. The first construction stage including the experimental hall, the primary beam line, and one secondary beam line (K1.8BR) has been completed at the end of December 2008. In order to handle the high intensity primary beam safely, we have developed many special devices working under severe radiation environment. The present article reports the current status of the Hadron Experimental Facility in detail.

The late Professor Kazuo Kondo (Department of Mathematics, Tokyo University, Japan) left a hitherto unknown a priori particle theory which provides predictions of massive particles which may be detected by the Large Hadron Collider (LHC) and related apparatus. This article briefly introduces Kondo's work and documents the derivation and masses of his expected hyper-mesons, hyper-hadrons, heavy leptons and massive neutrinos. Several particles in these classes may have already been detected.