Table of contents

In this article an attempt is made to review some of the original works leading to new developments of calorimeters which are so widely and successfully used in astro and particle physics experiments. This report is far from being complete and the author apologizes for omissions and misquotations.

Two low lying positive-parity bands in ¹³⁰Cs have been examined for chiral signatures. Small energy differences between the two bands, which have been previously observed, have been confirmed and the bands, as well as the number of transitions within and between the bands, extended. The intraband B(M1)/B(E2) ratios and B(M1)_intraband/B(M1)_interband ratios and the energy staggering parameter, S(I), have been deduced for these partner bands. The results are found to be consistent with a chiral interpretation for the two structures. Core–quasiparticle coupling model calculations have been performed to study ¹³⁰Cs assuming a triaxial core. The experimental level energies and electromagnetic properties of the bands, resulting from the configuration, are reasonably well reproduced by the model, providing further evidence in support of the chiral interpretation of the two structures.

A mass-separated ¹²C²²O molecular ion beam from the ISOLDE facility was used to study the decay of neutron-rich ²²O. The experimental results were compared with the results from an earlier experiment and predictions by shell-model calculations using various effective interactions. The mechanism leading to the vanishing decay strength to the first 1⁺ level of the ²²F nucleus, predicted with the USD effective interaction but not supported by the experimental data, is analysed.

We investigate the possibility of distinguishing between the standard model higgs boson and the lightest Higgs boson in split supersymmetry. We point out that the best way to distinguish between these two Higgs bosons is through the decay into two photons. It is shown that there are large differences of several per cent between the predictions for Γ(h → γγ) in the two models, making possible the discrimination in future photon–photon colliders. Once the charginos are discovered in the next generation of collider experiments, the well-defined predictions for the Higgs decay into two photons will become a cross check to identify the light Higgs boson in split supersymmetry.

We have investigated the possibility of ν_τ detection using a cosmic ray tau neutrino telescope (CRTNT) based on air shower fluorescence/Cerenkov light detector techniques. This approach requires an interaction of a ν_τ with material such as a mountain or the earth's crust. A τ lepton produced in the charged current interaction must escape from the earth and then decay and initiate a shower in the air. The probability for the conversion from ν_τ to air shower has been calculated for an energy range from 1 PeV to 10 EeV. An air shower simulation programme has been developed using the simulation package Corsika. The trigger efficiency has been estimated for a CRTNT detector similar to the HiRes/Dice detector in the shadow of Mt Wheeler in Nevada, USA. A rate of about eight triggered events per year is expected for the AGN neutrino source model with an optimized configuration and duty cycle of the detector.

The strangeness canonical ensemble for Maxwell–Boltzmann statistics is reconsidered for excited nuclear systems with non-vanishing net strangeness. A new recurrence relation method is applied to find the partition function. The method is first generalized to the case of quantum strangeness canonical ensemble. Uncertainties in the calculation of the K⁺/π⁺ excitation function are discussed. A new scenario based on the strangeness distillation effect is put forward for a possible explanation of anomalous strangeness production observed at the bombarding energy ∼30 GeV. The peaked maximum in the K⁺/π⁺ ratio is considered as a sign of the critical endpoint reached in evolution of the system rather than a latent heat jump emerging from the onset of the first-order deconfinement phase transition.

We consider the non-radiative two-body decay of a neutrino to a daughter neutrino with degraded energy and a very light particle (Majoron). Ultrahigh-energy neutrinos from an astrophysical source like a gamma ray burst undergoing this decay process are found to produce different number of events in the detector depending on whether they are Majorana or Dirac particles. The next generation large-scale experiments like Multi-OWL is expected to provide us an accurate determination of the flux of neutrinos from astrophysical sources and this may enable us to distinguish between the Dirac and Majorana nature of neutrino.

The coupling constant of ϕ → πγ decay is calculated using light-cone QCD sum rules. A comparison of our result with those existing in the literature is presented.

The lower excitation spectrum of the nucleon and Δ is calculated in a relativistic chiral quark model. Contributions of the second-order self-energy and exchange diagrams due to pion fields to the mass spectrum of the SU(2) baryons are estimated. A splitting between N(939) and positive parity nucleon resonance (Roper resonance) N*(1440) is reproduced with a reasonable accuracy. The obtained structure of one-meson exchange interaction confirms a prediction of the large N_c limit approach stating that the mass splitting between various baryon states receives contributions from operators which simultaneously couple spin, isospin and orbital momentum. It is shown that one-meson exchange interaction generates a splitting between negative parity N*(1/2⁻) and N*(3/2⁻) states, and also between Δ*(3/2⁻) and Δ*(1/2⁻) states in contrast to the non-relativistic Goldstone boson exchange based quark models.

For collisions between deformed and oriented nuclei, the fragmentation theory is extended for the generalized nuclear proximity potential, with deformations included up to the hexadecupole deformations. For co-planar nuclei, the orientations are shown to get optimized (uniquely fixed) by the signs of their quadrupole deformations alone, not affected by the signs of their hexadecupole deformations. The optimum orientations are obtained for both the 'hot compact', and 'cold elongated' configurations of any two colliding nuclei. The hexadecupole deformations are shown to help fusion (hot or cold), depending on the choice of the reaction partners. Calculations are made for the ²⁰⁸Pb- and ⁴⁸Ca-induced reactions and the neighbouring deformed nuclei. The calculated fragmentation potentials for optimally oriented nuclei, compared with both nuclei taken spherical, show that the excitation energy of the potential energy minima is significantly lowered for cold (elongated) fusion of deformed nuclei, but it remains nearly the same for at least the asymmetric hot (compact) fusion reactions. A number of new minima (target–projectile combinations) arise due to the cold and nearly symmetric hot fusion of deformed, optimally oriented nuclei.

We show that for Drell–Yan events by unpolarized hadronic projectiles and nuclear targets, azimuthal asymmetries can arise from the nuclear distortion of the hadronic projectile wavefunction, typically a spin–orbit effect occurring on the nuclear surface. The asymmetry depends on quantities that enter also the spin asymmetry in the corresponding Drell–Yan event on polarized free nucleonic targets. Hence, this study can be of help in exploring the spin structure of the nucleon, in particular the transverse spin distribution of partons inside the proton. All arguments can be extended also to antinucleon projectiles and, consequently, apply to possible future measurements involving nuclear targets at the foreseen HESR ring at GSI.

Covariant density functional theory (CDFT) is used to investigate superdeformation in Pb isotopes on the neutron rich side of the periodic table. Energy surfaces and deformation parameters in this region are calculated by solving the constrained relativistic Hartree Bogoliubov (RHB) equations. We use the parameter set DD-ME2, which has an explicit density dependence as well in the isoscalar as in the isovector channel together with the finite range pairing force D1S of Gogny. With increasing neutron number, we find a characteristic pattern for superdeformed minima in these nuclei.

The results of calculations of level densities ρ, in the vicinity of the neutron binding energy S_n, are presented. These results were obtained using the Böhning combinatorial method for the calculation of particle-hole state densities dependent on the number of decompositions of the nucleus excitation energy to energies of independent fermions. The calculation was based on the semi-classical model description in the computation of particle-hole state densities and then of the level densities ρ, and takes into account the existence of energy gaps Δ, located near the Fermi level, in a single particle level scheme. This procedure considerably improved and extended the Böhning calculation method. The results, which were obtained in this way for ρ, for 220 nuclei, reproduce the regularities observed in the experimental values of ρ, which are dependent on the neutron number N, and they agree with the experimental data within two orders of magnitude. In addition, the neutron resonance densities ρ were calculated on the basis of the particle-hole state densities obtained using the analytical formula from Böhning's paper. To make the calculations possible, the values of 'complexity' k, as given in the semi-classical model, and the spin factors R(J), according to the paper by Ryckbosch, were used.

We consider the most general neutrino mass matrix which leads to θ₁₃ = 0, and present the formulae needed for obtaining the neutrino masses and mixing parameters in that case. We apply this formalism to a model based on the lepton number and on the seesaw mechanism. This model needs only one Higgs doublet and has only two right-handed neutrino singlets. Soft breaking is accomplished by the Majorana mass terms of the right-handed neutrinos; if the -conserving and -breaking mass terms are of the same order of magnitude, then it is possible to obtain a consistent model with a solar mixing angle significantly smaller than 45°. We show that the predictions of this model, m₃ = 0 and θ₁₃ = 0, are invariant under the renormalization-group running of the neutrino mass matrix.

We consider a Majorana neutrino mass matrix with , in the basis where the charged-lepton mass matrix is diagonal. We show that this pattern for the lepton mass matrices can be enforced by extending the standard model with three scalar SU(2) triplets and by using a horizontal symmetry group . The type-II seesaw mechanism leads to very small vacuum expectation values for the triplets, thus explaining the smallness of the neutrino masses; at the same time that mechanism renders the physical scalars originating in the triplets very heavy. We show that the conditions allow both for a normal neutrino mass spectrum and for an inverted one. In the first case, the neutrino masses must be larger than 0.1 eV and the atmospheric mixing angle θ₂₃ must be practically equal to 45°. In the second case, the product sin θ₁₃|tan 2θ₂₃| must be of order one or larger, thus correlating the large or maximal atmospheric neutrino mixing with the smallness of the mixing angle θ₁₃.

In this paper, we study the magnetic moment of the pentaquark state Θ⁺(1540) with the QCD sum rules approach in the external electromagnetic field. The numerical results indicate that the magnetic moment of the pentaquark state Θ⁺(1540) is about .

We describe the hadronization of quark matter assuming that quarks creating hadrons coalesce from a continuous mass distribution. The pion and antiproton spectrum and the momentum dependence of the antiproton-to-pion ratio are calculated. This model reproduces fairly well the experimental data at RHIC energies.

We calculate the Debye and Meissner masses of a gauge boson in a material consisting of two species of massless fermions that form a condensate of Cooper pairs. We perform the calculation as a function of temperature, for the cases of neutral Cooper pairs and charged Cooper pairs, and for a range of parameters including gapped quasiparticles, and ungapped quasiparticles with both quadratic and linear dispersion relations at low energy. Our results are relevant to the behaviour of photons and gluons in the gapless colour–flavour-locked phase of quark matter. We find that the photon's Meissner mass vanishes, and the Debye mass shows a non-monotonic temperature dependence, and at temperatures of order the pairing gap it drops to a minimum value of order times the quark chemical potential. We confirm previous claims that at zero temperature an imaginary Meissner mass can arise from a charged gapless condensate, and we find that at finite temperature this can also occur for a gapped condensate.

The ultra-relativistic quantum molecular dynamics (UrQMD) model is developed for neutron spallation production from ≈1 GeV proton-induced reactions. Improvements in the dynamical content of the standard UrQMD model include: (i) an initial ground state which reproduces the experimental root mean square radii; (ii) a momentum-dependent Pauli potential and (iii) medium-modified angular distributions for quasi-inelastic NN scattering and the reverse NΔ → NN reaction. It is shown that, in conjunction with the generalized evaporation model, the improved UrQMD model is able to reproduce the whole energy-angle neutron double differential cross sections in the interactions of proton on Al, Fe and Zr at 1.2 GeV.

The unexpectedly large transverse polarization measured in the decay B → ϕK* poses the question whether it is accounted for as a strong interaction effect or possibly points to a hidden nonstandard weak interaction. We extend here the perturbative argument to the helicity structure of the two-body baryonic decay and discuss qualitatively on how the baryonic B decay modes might help us in understanding the issue raised by B → ϕK*. We find among others that the helicity +1/2 amplitude dominates the leading order in the decay and that unlike the B → VV decay the dominant amplitude is sensitive to the right-handed b → s current, if any, in the penguin interaction.

In the model of low-energy interactions near threshold (Ivanov A N et al 2004 Eur. Phys. J. A 21 11 (Preprint nucl-th/0310081), Ivanov A N et al 2005 Eur. Phys. J. A 23 79 (Preprint nucl-th/0406053)), we calculate isospin-breaking corrections to the energy level displacement of the ground state of kaonic hydrogen, investigated by Meißner, Raha and Rusetsky (2004 Eur. Phys. J. C 35 349 (Preprint hep-ph/0402261)) within the non-relativistic effective Lagrangian approach based on ChPT by Gasser and Leutwyler. Our results agree well with those by Meißner et al. In addition we calculate the dispersive corrections, caused by the transition with the pair on-mass shell. We show also how hypothesis on the dominant role of the -cusp for the S-wave amplitude of low-energy K⁻p scattering near threshold, used by Meißner et al, can be realized in our approach. The result agrees fully with that of Meißner et al.

The 'sling effect' appears when a fragment of a projectile nucleus emitted after its peripheral collision with a target nucleus is caused to rotate with high spin. The spinning fragment has a deformed shape and looks like an oblate ellipsoid. Due to the virtual non-compressibility of nuclear matter, and the polarization of the spin in the plane transverse to the input momentum of the projectile nucleus, such an ellipsoid has a reduced mean interaction cross-section compared with a non-spinning fragment which has a spherical shape. Purely geometrical arguments dictate that such an ellipsoidal nucleus should have additional fluctuations of cross-section even at a fixed impact parameter dependent on the orientation angle between the axis of the ellipsoid and the vector connecting the centres of the projectile and target nucleus. The number of 'wounded nucleons' in the projectile nucleus participating in the interaction correlates strongly with the interaction cross-section. All these effects lead to a non-exponential attenuation of fragments and an increased probability for a fragment to penetrate down to a larger depth in the absorber, than normal. If the sling effect appears in the interaction of a primary cosmic ray nucleus with nuclei in the atmosphere, the induced atmospheric cascade will have a slower attenuation, and thereby can help us to reduce some important inconsistencies in the interpretation of the existing experimental data on extensive air showers observed in the lower half of the atmosphere. The paper gives numerical estimates of the sling effect.

Properties of a hypothetical scalar baryonium with the quark content are discussed. The MIT bag model predicts its mass to be unexpectedly low, approximately 1210 MeV. Possible hadronic decay modes of this state are analysed. Ultrarelativistic heavy-ion collisions provide favourable conditions for the formation of such particles from the baryon-free quark–gluon plasma. We estimate multiplicities of such exotic baryonia on the basis of a simple thermal model.

Fluctuations in nuclear collisions can be measured as a function of momentum-space binning scale over a scale interval bounded by detector two-track resolution and acceptance. Fluctuation scale dependence is related to two-particle correlations by a Fredholm integral equation. That equation can be inverted by standard numerical methods to yield an autocorrelation distribution on difference variables as a projection of the full two-particle distribution which retains most of the correlation information in a more compact form. Autocorrelation distributions are typically more easily interpreted in terms of physical mechanisms than fluctuation measurements.

A new approach is proposed for a unified description of strongly coupled deep inelastic (DI) scattering, fusion, fission and quasi-fission (QF) processes of heavy-ion collisions. The standard (most important) degrees of freedom of the nuclear system, unified driving potential, and a unified set of dynamic equations of motion are used in this approach. This makes it possible to perform a full (continuous) time analysis of the evolution of heavy nuclear systems, starting from the approaching stage, moving up to the formation of the compound nucleus and eventually emerging into two final fission fragments. The calculated mass, charge, energy and angular distributions of the reaction products agree well with the corresponding experimental data. It gives us hope to obtain rather accurate predictions for the probabilities of superheavy element formation in near-barrier fusion reactions.

The low-lying spectrum of the quark model is shown to be robust under the effects of 'unquenching'. In contrast, the use of screened potentials is shown to be of limited use in models of hadrons. Applications to unquenching the lattice Wilson loop potential and to glueball mixing in the adiabatic hybrid spectrum are also presented.

The soft-pion theorem for pion production in deeply virtual Compton scattering, derived by Guichon, Mossé and Vanderhaegen, is shown to be consistent with chiral perturbation theory. Chiral symmetry requires that the nonsinglet operators corresponding to spin-independent and spin-dependent parton distributions have the same anomalous dimensions in the cases where those operators are related by chiral transformations. In chiral perturbation theory, their scale dependences can thus be absorbed in the coefficients of the corresponding effective operators, without affecting their chiral structures.

A calculation of the excitation energy of the 0⁺ states and of the 2⁺ states is performed using Monte Carlo methods for the nucleus ¹⁵⁴Dy. The Hamiltonian is assumed to be a monopole+quadrupole pairing+quadrupole with the parameters fixed by the spectroscopic Monte Carlo method so as to reproduce the experimental excitation energies of the yrast states up to J = 8 within the 50–82 and 82–126 proton and neutron major shells. The resulting Hamiltonian has been diagonalized in the J = 0 and J = 2 subspaces using the quantum Monte Carlo method. The size of the basis is fixed by comparing the yrast energies obtained with the basis-independent spectroscopic Monte Carlo method, and those obtained with the quantum Monte Carlo method. The excitation energy of the 0⁺₂ is much higher than the experimental value. The structure of the 0⁺_2,3 and of the 2⁺_2,3 eigenstates is discussed in terms of fluctuating intrinsic states and resolved in terms of the deformation variables.

On page 2338 of this paper, equation (5.8) should be corrected as

φ₂(λ) = (1 - λ){[(2λ - 3) / λ⁴] ln|1- λ²| - 3(1 - λ) / λ²} - 2

This appears in the PDF file in an alternative fractional format.