Development of 222Rn Emanation Sources with Integrated Quasi 2π Active Monitoring

In this work, a novel approach for the standardization of low-level 222Rn emanation is presented. The technique is based on the integration of a 222Rn source, directly, with an α-particle detector, which allows the residual 222Rn to be continuously monitored. Preparation of the device entails thermal physical vapor deposition of 226RaCl2 directly onto the surface of a commercially available ion implanted Si-diode detector, resulting in a thin-layer geometry. This enables continuous collection of well resolved α-particle spectra of the nuclei, decaying within the deposited layer, with a detection efficiency of approximately 0.5 in a quasi 2π geometry. The continuously sampled α-particle spectra are used to derive the emanation by statistical inversion. It is possible to achieve this with high temporal resolution due to the small background and the high counting efficiency of the presented technique. The emanation derived in this way exhibits a dependence on the relative humidity of up to 15% in the range from 20% rH to 90% rH. Traceability to the SI is provided by employing defined solid-angle α-particle spectrometry to characterize the counting efficiency of the modified detectors. The presented technique is demonstrated to apply to a range covering the release of at least 1 to 210 222Rn atoms per second, and it results in SI-traceable emanation values with a combined standard uncertainty not exceeding 2%. This provides a pathway for the realization of reference atmospheres covering typical environmental 222Rn levels and thus drastically improves the realization and the dissemination of the derived unit of the activity concentration concerning 222Rn in air.

Microscopic study of higher-order deformation effects on the ground states of superheavy nuclei around Hs-270

We study the effects of higher-order deformations βλ (λ = 4,6,8, and 10) on the ground state properties of superheavy nuclei (SHN) near the deformed doubly magic nucleus 270Hs by using the multidimensionally-constrained (MDC) relativistic mean-field (RMF) model with five effective interactions PC-PK1, PK1, NL3∗, DD-ME2, and PKDD. The doubly magic properties of 270Hs are featured by the large energy gaps at N = 162 and Z = 108 in the single-particle spectra. By investigating the binding energies and single-particle levels of270Hs in multidimensional deformation space, we find that the deformation β6 has the greatest impact on the binding energy among these higher-order deformations and influences the shell gaps considerably. Similar conclusions hold for other SHN near 270Hs. Our calculations demonstrate that the deformation β6 must be considered when studying SHN by using MDC-RMF.

Statistical Scrutiny of Particle Spectra in ep Collisions

Charged particle multiplicity distributions in positron–proton deep inelastic scattering at a centre-of-mass energy s = 300 GeV, measured in the hadronic centre-of-mass frames and in different pseudorapidity windows are studied in the framework of two statistical distributions, the shifted Gompertz distribution and the Weibull distribution. Normalised moments, normalised factorial moments and the H-moments of the multiplicity distributions are determined. The phenomenon of oscillatory behaviour of the counting statistics and the Koba-Nielsen-Olesen (KNO) scaling behaviour are investigated. This is the first such analysis using these data. In addition, projections of the two distributions for the expected average charged multiplicities obtainable at the proposed future ep colliders.

Muon g − 2 anomaly in anomaly mediation

The long-standing muon g − 2 anomaly has been confirmed recently at the Fermilab. The combined discrepancy from Fermilab and Brookhaven results shows a difference from the theory at a significance of 4.2 σ. In addition, the LHC has updated the lower mass bound of a pure wino. In this letter, we study to what extent the g − 2 can be explained in anomaly mediation scenarios, where the pure wino is the dominant dark matter component. To this end, we derive some model-independent constraints on the particle spectra and g − 2. We find that the g − 2 explanation at the 1σ level is driven into a corner if the higgsino threshold correction is suppressed. On the contrary, if the threshold correction is sizable, the g − 2 can be explained. In the whole viable parameter region, the gluino mass is at most 2 − 4 TeV, the bino mass is at most 2 TeV, and the wino dark matter mass is at most 1 − 2 TeV. If the muon g − 2 anomaly is explained in the anomaly mediation scenarios, colliders and indirect search for the dark matter may find further pieces of evidence in the near future. Possible UV models for the large threshold corrections are discussed.

GUT-constrained supersymmetry and dark matter in light of the new (g − 2)μ determination

The recent confirmation by the Fermilab-based Muon g-2 experiment of the (g − 2)μ anomaly has important implications for allowed particle spectra in softly broken supersymmetry (SUSY) models with neutralino dark matter (DM). Generally, the DM has to be quite light, with the mass up to a few hundred GeV, and bino-dominated if it is to provide most of DM in the Universe. Otherwise, a higgsino or wino dominated DM is also allowed but only as a strongly subdominant component of at most a few percent of the total density. These general patterns can easily be found in the phenomenological models of SUSY but in GUT-constrained scenarios this proves much more challenging. In this paper we revisit the issue in the framework of some unified SUSY models with different GUT boundary conditions on the soft masses. We study the so-called non-universal gaugino model (NUGM) in which the mass of the gluino is disunified from those of the bino and the wino and an SO(10) and an SU(5) GUT-inspired models as examples. We find that in these unified frameworks the above two general patterns of DM can also be found, and thus the muon anomaly can also be accommodated, unlike in the simplest frameworks of the CMSSM or the NUHM. We show the resulting values of direct detection cross-section for points that do and do not satisfy the muon anomaly. On the other hand, it will be challenging to access those solutions at the LHC because the resulting spectra are generally very compressed.

Direct-drive target designs as energetic particle sources for the Laser MégaJoule facility

This work aims to analyse the possibility of directly driven imploding spherical targets in order to create a source of energetic particles (neutrons, protons, alphas, tritium and 3He ions) for the Laser MégaJoule facility. D3He gas-filled spherical SiO2 glass pellets, irradiated by an absorbed laser intensity of 1014 W cm−2 or 1015 W cm−2 have been considered. Depending on the absorbed laser intensity and the amount of the ablated glass layer two distinct regimes have been identified: a massive pusher and an exploding pusher. Both regimes are analysed in terms of hydrodynamics and fast particle spectra. Energetic particle time-resolved spectra are calculated and used to infer ionic temperatures and total areal densities. A parametric study has been performed by varying the shell thickness and target inner radius for both laser absorbed intensities.

Medium effects of charged particles in Xe+Xe collisions at s NN = 5.44 TeV using modified Tsallis distribution

We present a systematic study of transverse momentum [Formula: see text] spectra of charged particles in [Formula: see text] and Xe[Formula: see text]Xe collisions at [Formula: see text] TeV. The published data of invariant yields of charged particles as a function of [Formula: see text] is taken from ALICE at LHC in the mid-pseudorapidity region [Formula: see text]. The modified form of Tsallis distribution is used here to analyze the [Formula: see text] spectra of charged particles. The power law of Tsallis/Hagedorn form gives very good description of the charged particle spectra in [Formula: see text] collisions within a [Formula: see text] range of 0.15 GeV/[Formula: see text] to 50 GeV/[Formula: see text]. When we go from [Formula: see text] collisions to heavy-ion (Xe[Formula: see text]Xe) collisions, the original form of Tsallis/Hagedorn distribution is not able to describe the [Formula: see text] spectra of charged particles properly. This may be occurred due to the medium effects or the final state effects. Here we discuss two types of medium effects of charged particles in Xe[Formula: see text]Xe collisions, one is the transverse flow in the low to intermediate [Formula: see text] region ([Formula: see text] GeV/[Formula: see text]) and the other is the energy loss in the high [Formula: see text] region ([Formula: see text] GeV/[Formula: see text]), using the modified Tsallis distribution.