Design of hadronic calorimeter for DarkSHINE experiment

The sensitivity of the dark photon search through invisible decay final states in low-background experiments relies sig-nificantly on the neutron and muon veto efficiencies,which depend on the amount of material used and the design of the detector geometry.This paper presents the optimized design of the hadronic calorimeter(HCAL)used in the DarkSHINE experiment,which is studied using a GEANT4-based simulation framework.The geometry is optimized by comparing a traditional design with uniform absorbers to one that uses different thicknesses at different locations on the detector,which enhances the efficiency of vetoing low-energy neutrons at the sub-GeV level.The overall size and total amount of material used in the HCAL are optimized to be lower,owing to the load and budget requirements,whereas the overall performance is studied to satisfy the physical objectives.

Relativistic Heavy Ion Collider and the Large Hadron Collider for Heavy Ion Fusion

Heavy Ion Fusion makes use of the Relativistic Heavy Ion Collider at Brookhaven National Lab and the Large Hadron Collider in Geneva, Switzerland for Inertial Confinement Fusion. Two Storage Rings, which may or may not initially be needed, added to each of the Colliders increases the intensity of the Heavy Ion Beams making it comparable to the Total Energy delivered to the DT target by the National Ignition Facility at the Lawrence Livermore Lab. The basic Physics involved gives Heavy Ion Fusion an advantage over Laser Fusion because heavy ions have greater penetration power than photons. The Relativistic Heavy Ion Collider can be used as a Prototype Heavy Ion Fusion Reactor for the Large Hadron Collider.

Status and Prospects of Exotic Hadrons at BelleⅡ

In the past 20 years,many new hadrons that are difficult to explain within the conventional quark model have been discovered in the quarkonium region;these are called exotic hadrons.The Belle I experiment,as the nextgeneration B factory,provides a good platform for exploring them.The charmonium-like states can be produced at Belle I in several ways,such as B meson decays,initial-state radiation processes,two-photon collisions and double charmonium production.Bottomonium-like states can be produced directly in e^(+)e^(-) colliding energies at Belle I with low continuum backgrounds.Belle I plans to perform a high-statistics energy scan from the BB threshold up to the highest possible energy of 11.24 GeV to search for new Y_(b)states with J^(PC)=1^(--),X_(b)[the bottom counterpart of χ_(c1)(3872),also known as X(3872)]and partners of Z_(b)states.We give a mini-review on the status and prospects of exotic hadrons at BelleⅡ.

Ionization Chamber Dosimetry for Conventional and Laser-Driven Clinical Hadron Beams

The practice of using the direct ionization radiation (electrons, protons, antiprotons, pions, ions, etc) or of the indirect ionization radiation (photons, neutrons, etc) in economy and social life has led to the introduction of the absorbed dose magnitude (ICRU 1953) defined as the energy absorbed per mass unit of the irradiated substance. This is a fundamental magnitude valid for any type of ionizing radiation, any irradiated material and any radiation energy. In case of clinical hadron beams generated by conventional accelerators or those controlled by lasers, IAEA TRS 398 recommends the absorbed dose to water. This may be determined employing the calorimeter method with water or graphite, chemical method, fluence based measurements as Faraday cups or activation measurements, and the ionization chamber method. In this paper the selected method was the thimble air filled ionization chamber method for determination of absorbed dose to water.

Hadron Multiplicity in Pb+Pb Collisions at√s=2.76 TeV from Color Glass Condensate

The pseudo-rapidity distribution of charged hadron multiplicity in Pb+Pb collisions at√s=2.76 TeV is studied by using Color Glass Condensate dynamics in the fixed coupling case.We fit the HERA experimental data with heavy parton mass effect to obtain saturation exponentλ=0.22.It is found that the charged hadron multiplicity can only describe after including heavy parton mass effect due to a large amount of heavy partons produced at large hadron collider(LHC)energy.The pomeron loop effect contribution to hadron production is also investigated.It shows that charged hadron multiplicity is underestimated by including the pomeron loop effect,which indicates that the pomeron loop effect may not exist at LHC energy.

A Mechanism for Hadron Molecule Production in <i>pp</i>(<i>p</i>) Collisions

The problem of understanding loosely bound hadron molecules prompt production at hadron colliders is still open: how is it possible that meson molecules with binding energy compatible with zero could be formed within the bulk of the hadrons ejected in very high energy collisions? Monte Carlo simulations have been performed in the literature, leading to production cross sections, two orders of magnitude which were smaller than the experimental value. One possible mechanism to reduce this gap could be final state interactions of heavy mesons, but a precise evaluation of such effect is challenged by the presence of pions between the molecular constituents. In this paper, we present a new mechanism by using precisely such comoving pions. Heavy meson pairs can indeed slow down because of elastic scattering with surrounding pions. The number of low-relative-momentum meson pairs increases, thereby enhancing prompt production cross section. In this preliminar simulation, we show that an enhancement of 100 is indeed possible.

Effects of bulk viscosity on hadron spectra and the Hanbury-Brown Twiss radius by causal viscous hydrodynamics

The particle spectra and Hanbury-Brown Twiss （HBT） radius of Au＋Au collisions at RHIC energy are investigated by a hydrodynamical expanding source with both shear and bulk viscosities （ζ）. With a large width of the ratio of ζ to entropy density s, both the particle transverse momentum spectra and the ratio Rout/Raide Of HBT radii in the direction of the total transverse momentum of detected two particles （Rout） and perpendicular to both this direction and the beam direction （Rside） become a little steeper.

Quark Transport Properties in the Region of Coexistence of Both Hadronic and QGP Phases

The physical picture of coexistence of both hadronic and QGP phases is given by Friedberg and T.D. Lee's nontopology soliton model. The transport properties of quark in color space and spin space in a system of two-phase coexistence are investigated from both quantum and classical theories.

The Elliptic Flow of Multi-Strange Hadrons in [S_(NN)]^(1/2)= 200 GeV Au + Au Collisions at STAR

Azimuthal anisotropy, especially for the multi-strange hadrons, is expected to be sensitive to the dynamical evolution in the early stage of high energy nuclear collisions. In this paper we present the latest results of multi-strange hadron elliptic flow in Au ＋ Au collisions at √SNN=200GeV from the STAR experiment at RHIC. The number-of-quark scaling is evidenced with φ（ss） and Ω（sss） with highly statistical data, which shows strange quark collectivity at RHIC. The u2 of φ meson is found to be consistent with that of proton within statistical error bars at pw 〈 1 GeV/c.

Dependence of Long Range Correlation on Width of Rapidity Gap in High Energy Hadron-Hadron Collisions

The dependence of long range correlation in high energy hadron-hadron collisions on the width of rapidity gap is studied,It is shown that the result from a model with only one particle source does not fit the experimental data.In order to get the experimental dependence of long range correlation on the width of rapidity gap at least three particle sources are needed.

IMPROVED CALCULATION OF HADRONIC VACUUM POLARIZATION CORRECTIONS TO PHOTON PROPAGATOR

The hadronic vacuum polarization correction to the photon propagator is found by using the Dubnicka-Meshcheryakov parametrization of the pion form factor and new experimental data on the e^(+)e^(-)→hadrons anniKilation cross section.

Hadronic Transport Effects on Elliptic Flow

Elliptic flow v2 is considered as a probe to study partonic collectivity,and the measurement v2/εcan be used to describe the hydro behavior of the colliding system.We study the the effect of the hadronic process on the momentum anisotropy parameter v2 in a multiphase transport model.It is found that hadronic rescattering will depress the v2 signal built up at the partonic phase.A similar mass hierarchy is observed in the model as in the experiment at RHIC.We find that different particle species will approach the same ideal hydro limit if the hadronic process is excluded.

Single t-Quark Productions via Flavor-Changing Processes in Topcolor-Assisted Technicolor Model at Hadron Colliders

In the framework of topcolor-assisted technicolor （TC2） model, there exist tree-level flavor-changing （FC） couplings, which can result in the loop-level FC coupling tcg. Such tcg coupling can contribute significant clues at the forthcoming Large Hadron Collider （LHC） experiments. In this paper, based on the TC2 model, we study some single t-quark production processes involving tcg coupling at the Tevatron and LHC： pp（pp） → tq （q = u, d, s）, tg. We calculate the cross sections of these processes. The results show that the cross sections at the Tevatron are too small to observe the signal, but at the LHC it can reach a few pb. With the high luminosity, the LHC has considerable capability to find the single t-quark signal produced via some FC processes involving coupling tcg. On the other hand, these processes can also provide some valuable information of the coupling tcg with detailed study of the processes and furthermore provide the reliable evidence to test the TC2 model

Calculation of a Three-Jet Cross Section via the e^(+)e^(−)→Hadronic Rindler Horizon→qqg Process

The cross section for three-jet events via the e^(+)e^(−)→hadronic Rindler horizon→qqg process is compared to experimental data from the OPAL collaboration.It is found that the model is consistent with the QCD experiments.

NEW METHOD IN CALORIMETRY FOR SUPERHIGH ENERGY HADRONS

A new method in calorimetry for superhigh energy hadrons is proposed.The main feature of the method is the effective detection of soft neutrons,abundantly present in the superhigh energy hadron showers,by using neutron detectors insensitive to minimum ionizing particles.Such a calorimeter allows us to selectively detect the hadrons in the environment of high backgrounds of electrons,photons and muons.

THE ROLE OF PARTON HARD SCATTERING IN HADRONIC INTERACTIONS

A soft-hard two-component approach to the description of high energy hadronic interactions is proposed.It shows the important role of parton hard scattering in explanation of the chief characteristics of high energy hadronic interactions.

Charged Top-Pion Production at Hadron Colliders

We studied the charged top-pion in the topcolor assisted technicolor model(TC2).If the charged top-pionsare heavy,m_(πt)>m_t+m_b,they will decay mainly via the channel π_t^+→tb^-.We also calculated the production of chargedtop-pion at the Tevatron and LHC.The cross section can reach to 100 fb at the Tevatron and dozens of pb at the LHCdepending on the mass of the top-pion.

Influence of Hyperon-Hyperon Interaction on Properties of Hadronic Star

The influences of hyperon-hyperon interaction on the overall properties of hadronic star are investigated in the framework of relativistic mean field （RMF） theory. For certain hyperon coupling, the weaker hyperon-hyperon interaction can lead to the heavier hadronic star, which accords with the observation of heavy neutron star in X-ray binaries. We find that the threshold densities of the hyperons with larger masses are brought to a lower values with the increase of the hyperon-hyperon interaction. The possibility of the existence of hyperon star is checked with the consideration of hyperon-hyperon interaction.

Rapidity and Pseudorapidity Distributions of theVarious Hadron-Species Produced in High EnergyNuclear Collisions: A Systematic Approach

With the help of a phenomenological approach outlined in the text in some detail, we have dealt here with the description of the plots on rapidity and pseudorapidity spectra of some hadron-secondaries produced in various nucleus-nucleus interactions at high energies. The agreement between the measured data and the attempted fits are, on the whole, modestly satisfactory excepting a very narrow central region in the vicinity of y = η = 0. At last, hints to how the steps suggested in the main body of the text to proceed with the description of the measured data given in the plots could lead finally to a somewhat systematic methodology have also been made.

A New Strategy for Solving Two Cosmological Constant Problems in Hadron Physics

A new approach to solving two of the cosmological constant problems (CCPs) is proposed by introducing the Abbott-Deser (AD) method for defining Killing charges in asymptotic de Sitter space as the only consistent means for defining the ground-state vacuum for the CCP. That granted, Einstein gravity will also need to be modified at short-distance nuclear scales, using instead a nonminimally coupled scalar-tensor theory of gravitation that provides for the existence of QCD’s two-phase vacuum having two different zero-point energy states as a function of temperature. Einstein gravity alone cannot accomplish this. The scalar field will be taken from bag theory in hadron physics, and the origin of the bag constant B is accounted for by gravity’s CC as B—noting that the Higgs mechanism does not account for either the curved-space origin of λ or the mass of composite hadrons. A small Hubble-scale graviton mass mg^10-33eV naturally appears external to the hadron bag, induced by λ≠0. This mass is unobservable and gravitationally gauge-dependent. It is shown to be related to the cosmological event horizon in asymptotic de Sitter space.