Kaon decay studies at CERN SPS in the last decades

This review summarizes the kaon experimental results obtained in the last 15 years on the basis of data collected on the SPS in CERN with a participance of JINR physicists. These results contribute essentially into the Standard Model checks and search for its extension, fundamental symmetry violations and low energy strong interactions theory development. A progress in the experimental technique and prospects for the future results are also discussed.     

Status and plans of the ion program of NA61 at the CERN SPS

The NA61/SHINE at the CERN SPS is a new experiment to study hadron production in p+p, p+A, h+A and A+A interactions. The main goal of the NA61 ion program is to explore the phase diagram (T ? ?? _B ) of strongly interacting matter. In particular, we plan to study the properties of the onset of deconfinement and to search for the signatures of the critical point. A two-dimensional scan of the phase diagram will be performed by varying the energy (13A?C158A GeV) and system size (p+p, Be+Be, Ar+Ca, Xe+La) of collisions. This paper summarizes the status and plans of the NA61/SHINE ion program. In particular the detector upgrades, data taking schedule and the first results on spectra and correlations are discussed.     

Cosmic ray spectrum measured by the PRISMA-32 setup

The results of measurements of the spectrum of extensive air showers (EASs) by the number of neutrons detected by the PRISMA-32 setup are presented. The neutron component is formed during the interaction of high-energy shower hadrons with nuclei of atmospheric and Earth’s surface atoms. The PRISMA-32 setup consists of 32 en-detectors and operates in the continuous mode for about 5 years.     

Cosmic ray air showers in the knee energy region

The cosmic ray extensive air showers in the knee energy region have been studied by the North Bengal University array. The differential size spectra at different atmospheric depths show a systematic shift of the knee towards smaller shower size with the increase in atmospheric depth. The measured values of spectral indices at below and above the knee are −2.45 ±0.03 and −2.91 ±0.05 respectively. Measurements at different atmospheric depths correspond to the same values within the error limits both for below and above the knee. The present experimental results have been compared with similar such experiments     

Cosmic ray studies on the ISS using SSNTD, BRADOS projects, 2001–2003

The BRADOS 1–3 projects were organised by the Russian Space Agency (RZA) between 2001 and 2003. The aim was to study the contribution of the primary galactic cosmic rays and of the secondary particles to the dose received by the crew of the International Space Station (ISS). Several laboratories participated in these experiments. Two different stacks (constructed by the team of the Atomic Energy Research Institute, AERI, Budapest, Hungary) composed of solid-state nuclear track detectors (SSNTD) were exposed inside the Service Module at different locations. The calibrations were made at the CERN high-energy neutron reference field named CERF (Geneva, Swiss). Applying a multiple track etching technique (2–20 h etching time) and a sophisticated image analyser, the secondary neutron dose was deduced. The composition of stacks, the evaluation methods and the results will be presented here or referenced to previous papers.     

大型强子对撞机时代的宇宙线实验

随着大型强子对撞机（LHC）对撞实验的深入进行,宇宙线实验中许多不确定因素将在实验中确定下来,而大型的、多种探测手段的联合观测将把宇宙线实验研究推入精确测量的时代,对可能的宇宙线起源模型的限制将增强,对电子、各种核乃至γ光子和中微子的精确测量,将增加揭开宇宙线起源这一世纪谜团、甚至于寻找到暗物质源的可能性,而亟待解决的基本问题是利用高山地面实验装置,通过与空间直接测量的相互标定,确定能量标度并传递到能谱截断的极高能区,实现完整、一致、单一和可靠的宇宙线能谱、成分和到达方向各向异性度的测量.     

Cosmic ray sea level muon spectrum at large zenith angle derived from the latest JACEE primary spectrum

The sea level cosmic ray muon spectrum at 89° has been estimated from the primary nucleon spectrum estimated after the latest JACEE measurements. The p-A collision cross section has been considered for hadronic energy moments calculations. The meson atmospheric diffusion equations after Bugaev et al. have been used in this analysis. The calculated large zenith angle muon spectrum is well in accord with the latest MUTRON data for cosmic ray muons arriving at zenith angles 86° to 90°.On leave from Indian Association for the cultivation of Science, Calcutta 700032, India.     

Cosmic ray muons at a depth of 754 hg/cm2 in the Kolar gold Mines

A telescope of area 4 m², consisting of horizontal layers of plastic scintillators, neon flash tubes and absorbers was operated at a depth of 754 hg/cm² in the Kolar Gold Mines. New values for the vertical intensities of muons have been obtained from observations of the angular distribution over the slant depths ∼ 750–2300 hg/cm² and are compared with the existing measurements. From the angular distribution observed, we conclude that muons are produced wholly through the decay of pions and kaons up to energies of the order of 1 TeV. A value of 0.3±0.2 is estimated for theK/π ratio at production, for muon energies around 500 GeV. A decoherence distribution has been obtained for parallel muon events up to distances of the order of 10 m. From this we conclude that the averageP _t of the parents of muons of energy ∼ 250 GeV is of the order of 0.3 GeV/c. From an analysis of rock showers, we obtain the cross section for inelastic interaction of muons of mean energy 100 GeV as (3.8±1.5)×10⁻³⁰ cm²/nucleon.     

Cosmic ray electron spectrum due to the dispersion of injection spectrum

The cosmic-ray total electron spectrum(electrons plus positrons) has been measured precisely up to Te V energies,with more interesting features found.Exhaustive analyses of the electron spectrum strongly support a spectral hardening above 100 GeV,rather than a featureless single power-law,which is confirmed by the most recent observations.Meanwhile,the measurements of the DAMPE satellite have verified the presence of a knee-like structure around 1 TeV in the electron spectrum,resembling the cosmic-ray knee.In this paper,we establish a physical model in which the observed electron spectrum is composed of a superposition of CR sources with various spectral indices and high-energy cutoffs.The dispersion of the power index is assumed to be Gaussian,while the cutoff energy Ec follows a power-law distribution.These simple ideas can account naturally for both the hundred-GeV excess and the TeV spectral break.     

Inclusive Pomeron-Pomeron interactions at the CERN ISR

Data are presented for the first time on inclusive Pomeron-Pomeron interactions which produce a central systemX (composed mainly of multimeson states) in proton-proton collisions at \(\sqrt s \) at the CERN ISR. The systemX has a Feynman-x distribution which is sharply peaked atx _f=0, is inconsistent with any significant contributions from Reggeon exchange processes, and has an invariant mass dependence in good agreement with the predicted formM _x ^?2 . Kaon production is about 15% of pion production, nearly independent ofM _x, while proton-antiproton production averages about 5% of pion production and increases withM _x. The structure of the central systemX develops into a jetlike shape, asM _x increases, as would be expected from a model of Pomeron fragmentation. The shape of thex _f(π) distribution in the center of mass of theX system (although not proving existence) is consistent with asoft partonic substructure of the Pomeron.     

Atomic Physics Studies at the Gamma Factory at CERN

The Gamma Factory initiative proposes to develop novel research tools at CERN by producing, accelerating, and storing highly relativistic, partially stripped ion beams in the SPS and LHC storage rings. By exciting the electronic degrees of freedom of the stored ions with lasers, high-energy narrow-band photon beams will be produced by properly collimating the secondary radiation that is peaked in the direction of ions' propagation. Their intensities, up to 10¹⁷ photons per second, will be several orders of magnitude higher than those of the presently operating light sources in the particularly interesting γ–ray energy domain reaching up to 400 MeV. This article reviews opportunities that may be afforded by utilizing the primary beams for spectroscopy of partially stripped ions circulating in the storage ring, as well as the atomic-physics opportunities made possible by the use of the secondary high-energy photon beams. The Gamma Factory will enable ground-breaking experiments in spectroscopy and novel ways of testing fundamental symmetries of nature.     

Lead beam experiments at the CERN SPS

The acceleration in 1986 of¹⁶O beams to 200 GeV/nucleon at the CERN SPS created a new frontier of particle and nuclear physics, namely the study of high energy density systems with hundreds of quarks and gluons created in the central collisions of nuclei with heavy targets. In order to produce the largest piece of “quark matter”, beams as heavy as²⁰⁸Pb are needed. The Lead-Injector Project that would provide them is presented. Possible experimental approaches to extract the physics from collisions with thousands of produced particles are discussed.     

Cosmic ray constraints on the annihilations of relic particles in the galactic halo

We re-evaluate the fluxes of cosmic ray antiprotons, positrons and gamma rays to be expected from the annihilations of relic particles in the galactic halo. We stress the importance of observational constraints on the possible halo density of relic particles, and specify their annihilation cross sections by the requirement that their cosmological density close the Universe. We use a Monte Carlo programme adapted to fit e⁺e⁻ data to calculate the p̄, e⁺ and γ spectra for some supersymmetric relic candidates. We find significantly smaller p̄ fluxes than previously estimated, and conclude that present upper limits on cosmic ray p̄ and e⁺ do not exclude any range of sparticle masses. We discuss the prospects for possible future constraints on sparticles from cosmic γ rays.     

Cosmic ray intensity dynamics in the region ahead of the interplanetary shock front

The galactic cosmic rays intensity dynamics prior to the onset of the geomagnetic storm of September 9, 1992, are calculated using a new kinetic method. A comparison of the calculation results and the observational data from ground-level detectors shows satisfactory agreement on both amplitude and time.     

Proton-antiproton physics at the CERN intersecting storage rings

The storing of antiprotons in the CERN ISR allowed the comparison of proton-proton and proton-antiproton interactions through a variety of reactions ranging from total cross section measurements to hard scattering processes. This article reviews the results obtained at the ISR on such comparisons.