Study Of Hadronic Interactions Research Articles

Particle production and entropy measurement in ALICE

One of the main goals in the study of hadronic interactions at LHC energies is the attempt to characterize the mechanisms involved in particle production in different regimes. The charged-particle multiplicity is one of the most interesting observables in these kind of studies. Measurements of chargedparticle pseudorapidity densities in pp collisions at √s = 13.6 TeV are presented, for the first time. Furthermore, we present a method for better understanding the collision dynamics. On the one hand, the pseudorapidity dependence of charged-particle production provides information on the partonic structure of the colliding hadrons and is sensitive to non-linear QCD evolution in the initial state. On the other hand to understand the thermal-like behavior and particle yields in pp collisions, a possible approach is to address the principles of quantum states and their entanglement in the produced system. The entanglement in the initial state has a measurable effect on the evolution of the system and is the driving mechanism behind the thermal-like behavior and particle yields observed. We describe a method to understand the level of entanglement in the initial and final states of the collision using a calculation of entropy, the final-state entropy being calculated from multiplicity distributions.

Vector meson-nucleon scattering length $$|\alpha _{VN}|$$ and trace anomalous energy contribution to the nucleon mass $$T_{A}$$

Low-energy scattering processes of vector meson and nucleon are an important window for studying non-perturbative QCD. The interaction of vector meson with nucleon, vector meson-nucleon scattering length $|\alpha_{VN}|$, is an important component of the study of hadronic interactions. Nowadays many scattering length values $|\alpha_{VN}|$ have been reported using the recent photoproduction experiment data or quasi data. In addition, the study of trace anomalous energy contribution to the proton mass is also a hot topic in non-perturbative QCD and hadron physics. However, it is difficult to measure proton trace anomalous energy experimentally, and the study of the trace anomaly of proton is still inconclusive. In this study, we established the relationship between the scattering length of the vector meson-proton $|\alpha_{Vp}|$ and the trace anomaly contribution of the proton mass $T_{A}$. With the scattering length values extracted by using the Vector Meson Dominance model, we obtained the trace anomaly contribution of the proton mass $T_{A}$ = (22.8$\%$ $\pm$ 1.2$\%$), which is of similar order of magnitude as the 23$\%$ given by Lattice QCD calculation. We conjecture that the trace anomaly contribution of nucleon is independent of the type of vector meson probe. We hope that high precision measurements of vector meson-nucleon scattering length could give us a better chance to explore the origin of the nucleon mass.

Monte Carlo simulation of the cosmic muon charge ratio

The muonic component of air showers is sensitive to the mass and energy of the primary cosmic ray and is the most abundant component of charged particles arriving at the surface, and able to penetrate deep underground. The muon charge ratio, defined as the number of positive over negatively charged muons, is a very interesting quantity for the study of hadronic interactions at high energies and the nature of cosmic ray primaries. Furthermore, Earth's atmosphere is the development medium of cosmic air showers before they arrive at the ground. Therefore, variations in the density of the atmosphere between seasons must be studied. It is also very important to account for the zenith angular dependence of atmospheric muons, in particular for showers penetrating the atmosphere at high zenith angles. We present a study of the muon charge ratio using Monte Carlo simulations of two cosmic primaries, proton, and iron, of 100 TeV and 1 PeV energies, and with a zenith angle of 0° to 60°. The dependence on the direction of extensive air showers EAS and their radial distance appears to be very pronounced. In addition, the muon density is discussed assuming the Central European Atmosphere in June and December.

“HADRON-55” complex setup for study of hadron interactions within the central part of cosmic ray extensive air showers (EAS) cores

“HADRON-55” with scintillation detectors and ionization calorimeters is used for studies in high-energy gamma-astronomy and cosmic ray physics. The “HADRON-55” consists of two parts - the upper gamma block and the lower hadron block. The gamma block absorbs and detects the electron-photon components of cosmic rays, while hadrons are not absorbed when they pass through the gamma block and begins to form particles in the hadron block. Project's main idea is to select events where there is the interaction in gamma block and no interaction in hadron block. Analysis of experiments results on “HADRON-55” accounts for ∼ 6% of such events. The peripheral part of “HADRON-55” consists of 8 scintillation detectors placed in 2 circles with radii of 40 and 100 m. Over 4 years, more than 120,000 events with high energy of 1015 eV were detected.

Amplitude analysis of the KSKS system produced in radiative J/ψ decays

An amplitude analysis of the $K_{S}K_{S}$ system produced in radiative $J/\psi$ decays is performed using the $(1310.6\pm7.0)\times10^{6}$ $J/\psi$ decays collected by the BESIII detector. Two approaches are presented. A mass-dependent analysis is performed by parameterizing the $K_{S}K_{S}$ invariant mass spectrum as a sum of Breit-Wigner line shapes. Additionally, a mass-independent analysis is performed to extract a piecewise function that describes the dynamics of the $K_{S}K_{S}$ system while making minimal assumptions about the properties and number of poles in the amplitude. The dominant amplitudes in the mass-dependent analysis include the $f_{0}(1710)$, $f_{0}(2200)$, and $f_{2}^\prime(1525)$. The mass-independent results, which are made available as input for further studies, are consistent with those of the mass-dependent analysis and are useful for a systematic study of hadronic interactions. The branching fraction of radiative $J/\psi$ decays to $K_{S}K_{S}$ is measured to be $(8.1 \pm 0.4) \times 10^{-4}$, where the uncertainty is systematic and the statistical uncertainty is negligible.

Hadrons in the CALICE silicon-tungsten electromagnetic calorimeter

A detailed study of hadronic interactions is presented using data recorded with the highly granular CALICE silicon-tungsten electromagnetic calorimeter. The predictions of several Monte Carlo Geant4 models are compared with experimental data, taken at FNAL in 2008. The contribution recaps results published in 2015 and a set of new results available since the beginning of 2016. The published results present a detailed analysis of hadronic showers in terms of radial and longitudinal hit and energy distributions. For the most recent analysis a simple track-finding algorithm was developed to study tracks left by secondary particles, emerging from hadronic interactions in the highly granular electromagnetic calorimeter prototype. Present Monte Carlo simulations provide a good description of the experimental data in terms of new observables, available through the detailed analysis of secondary particles; the Monte Carlo predictions are within 20% of the data, and for many observables much closer.

Testing hadronic interaction models using a highly granular silicon–tungsten calorimeter

A detailed study of hadronic interactions is presented using data recorded with the highly granular CALICE silicon–tungsten electromagnetic calorimeter. Approximately 350,000 selected π− events at energies between 2 and 10GeV have been studied. The predictions of several physics models available within the GEANT4 simulation tool kit are compared to this data. A reasonable overall description of the data is observed; the Monte Carlo predictions are within 20% of the data, and for many observables much closer. The largest quantitative discrepancies are found in the longitudinal and transverse distributions of reconstructed energy.

Study of hadron interactions in a lead-emulsion target

Topological and kinematical characteristics of hadron interactions have been studied using a lead-emulsion target exposed to 2, 4 and 10 GeV/c hadron beams. A total length of 60 m $\pi^-$ tracks was followed using a high speed automated emulsion scanning system. A total of 318 hadron interaction vertices and their secondary charged particle tracks were reconstructed. Measurement results of interaction lengths, charged particle multiplicity, emission angles and momenta of secondary charged particles are compared with a Monte Carlo simulation and appear to be consistent. Nuclear fragments emitted from interaction vertices were also detected by a newly developed emulsion scanning system with wide-angle acceptance. Their emission angle distributions are in good agreement with the simulated distributions. Probabilities of an event being associated with at least one fragment track are found to be greater than 50% for beam momentum $P > 4$ GeV/c and are well reproduced by the simulation. These experimental results validate estimation of the background due to hadron interactions in the sample of $\tau$ decay candidates in the OPERA $\nu_{\mu} \to \nu_{\tau}$ oscillation experiment.

Design of the pluto event generator

We present the design of the simulation package Pluto, aimed at the study of hadronic interactions at SIS and FAIR energies. Its main mission is to offer a modular framework with an object-oriented structure, thereby making additions such as new particles, decays of resonances, new models up to modules for entire changes easily applicable. Overall consistency is ensured by a plugin- and distribution manager. Particular features are the support of a modular structure for physics process descriptions, and the possibility to access the particle stream for on-line modifications. Additional configuration and self-made classes can be attached by the user without re-compiling the package, which makes Pluto extremely configurable.

The AMADEUS experiment at DAΦNE and the analysis of KLOE data in the search for kaonic nuclear clusters

The AMADEUS experiment will perform for the first time full-acceptance studies of hadronic interactions of K − in light nuclei, with a complete experimental program for the case of the deeply bound kaonic nuclear states. The possible formation of a kaonic cluster could provide information concerning the modification of the kaon mass and of the \(\overline{K}N \) interaction in the nuclear medium. In order to confirm or deny the existence of such exotic objects, the detection of all particles in the formation and decay processes will be performed, taking, moreover, advantage of the high luminosity reached by the recently upgraded DAΦNE accelerator. A preliminar study of this kind of hadronic interaction is being done by the AMADEUS collaboration by analyzing the KLOE data.

PHOKHARA, the radiative return and the [formula omitted] puzzle

The radiative return has proven to be a competitive method for the precise measurement of the hadronic cross section, detailed studies of hadronic interactions, and even discoveries of new resonances. The most recent and future developments of the Monte Carlo event generator PHOKHARA are highlighted, and the impact of the radiative return measurements on the ( g − 2 ) μ puzzle is discussed.

Nuclear Physics with Lattice QCD

We discuss recent progress and future prospects of the application of lattice QCD to the study of hadronic interactions. In particular, we review the issues arising in a first principles calculation of the nuclear force.

Interactions of hadrons and nuclei at superhigh energies and small-x physics

A connection between high-energy interactions of hadrons and nuclei and small x deep inelastic scattering (DIS) is discussed. It is pointed out that an information on properties of the Pomeron, which was obtained from studies of hadronic interactions is very important for understanding the main features of experimental data on small x DIS. The Quark Gluon Strings Model (QGSM) and the Dual Parton Model (DPM) of high-energy hadronic interactions are reviewed and an important role of multi-Pomeron exchanges is emphasized. It is shown that the models, which well describe hadronic interactions are also in a good agreement with recent results on small-x DIS from HERA.

Cosmic ray composition and interactions: measurements at the knee

Some characteristics of Extensive Air Showers in the energy region of the knee of the cosmic ray spectrum (Eo = 1015 – 1016 eV) are discussed, to discriminate its possible “hadronic” from “astrophysical” origin. Within the accuracy of such data, no clear “anomaly” suggesting a non expected behaviour of hadronic collisions at such energies is observed. Some approaches to the study of hadronic interactions, as observable through EAS experiments, are discussed. Such data can be significant to test the high energy interaction models used for composition analysis.

Study of the quark gluon string model predictions

We have studied some properties of the secondary particles in p-p interactions which are obtained on the basis of the quark gluon string model. This model is tuned with FNAL and ISR data at 20 GeV. The rise of the predicted inelastic cross section agrees with accelerator data up to 1.9 Tev (SCM). The asymptotic behaviour of secondary particle spectra with scaling in the fragmentation region leads to a rather slow rise of multiplicity. An improved parametrization will help the study of hadron interactions at the highest energies and explain some exotic events which are observed in cosmic ray experiments.

Production of String-Loops and Rising of Central Plateau in SPS Collider Region

From the viewpoint that hadronic reactions arise from creation of excited strings, the rising of the central plateau, which has been recently observed in the SPS Collider region, is interpret· ed to be due to the production of string· loops on the excited strings. It is predicted that the central plateau grows up steadily in conjunction with the initial increase of the averaged baryon multiplicity but approaches an asymptotic height at energies much higher than the SPS Collider range. Since the successful operation of the CERN SPS Collider, the experimental studies of hadronic interactions have been undertaken at the energy .fS = 540 GeV (PL 155 TeV Ie). The new data on!5p collisions have exhibited the salient rising of the central plateau in rapidity.!) How can we explain the observed rising in terms of the existing models? From the viewpoint of the topological 1/ Nc expansion,2) the multi-hadron production is considered to take place through two steps.3)- 7) The first step is the creation of some excited strings and the second step consists of independent breakups of the strings. We have two excited strings in the first step for the Pomeron part, which dominates at TeV region.*) Namely, above the ISR energy the central plateau may be ascribed to the fragments of two excited strings which are long enough in rapidity to saturate the central plateau in height for !5P collisions. 3 ) The observed rising accordingly seems to be suggesting a new mechanism for multi-hadron production being disclosed at TeV region. It is therefore very instructive to investigate the possibility that excited strings imply some folded structure. In this paper we propose as such, the mechanism of the string-loop production on excited strings which is brought about at some thresh­ old value and becomes predominant at TeV region, as illustrated in Fig. 1,**) and show that this mechanism gives a consistent description of the experimental features.

On the Detection of Heavy Primaries above 1014 EV

Knowledge of the chemical composition is fundamental to understanding the origin, acceleration and propagation of cosmic rays. At energies much above 1014 eV, however, the detection of single primary cosmic rays is at present impossible because of their low flux, and the only source of information is from the cascades initiated by energetic primary particles in the atmosphere–the extensive air showers (EAS). A similar situation exists for the study of hadronic interactions above 1015 eV. A recent EAS experiment (Goodman et al., 1979) suggests the possibility that the spectrum becomes increasingly rich in heavy nuclei as the total energy per nucleus approaches 1015 eV. Above that energy the overall spectrum steepens and the question of composition is almost completely open.

Study of hadron interactions in cosmic rays

Study of hadron interactions in cosmic rays

Izuchenie vzaimodeistvii adronov v kosmicheskikh luchakh

Izuchenie vzaimodeistvii adronov v kosmicheskikh luchakh

Generalized quark-line rule inSU 4 symmetry scheme

Recently, APEL et at. (1) have reported the observation of the cross-section for ~-p-+~on at 40 GeV/o incident pion momentum. CESTE~ e t a l . (2) have measured ~ ~ + D T * B o cross-section near the threshold 10.5GeV/c through carbon target. Pluto collaboration (s) has informed the observation of J/~ radiative decay into fo(I270)y. This is considered as an additional example of the two-body photonie decays of vector-tensor case, supplementing the known two-gamma cascade ~(3684)-~ -~ xT(a550)y-~ J / ~ V ('). 0KUBO (~) has discussed repeatedly the quark-line (known as 0kubo-Z~ceig-Iizuka) rule (QLR) (6) in a great detail by generalizing the original idea. The recent experimental works stated at the first paragraph and relevant problems will give a further insight to disclose the content of the QLR. The present author thinks that the study of hadron interactions under the assumption of strict QLR will give an important guido for constructing the future theory of hadron dynamics (D. The purpose of this paper is to generalize the quark-line in the form of 0kubo to SU, symmetry scheme and to analyse the consequences from that point of view.