Hasil untuk "Nuclear and particle physics. Atomic energy. Radioactivity"

Diego Delmastro, Adar Sharon, Yunqin Zheng

Abstract We embark on a systematic study of continuous non-invertible symmetries, focusing on 1+1d CFTs. We describe a generalized version of Noether’s theorem, where continuous non-invertible symmetries are associated to non-local conserved currents: point-like operators attached to extended topological defects. The generalized Noether’s theorem unifies several constructions of continuous non-invertible symmetries in the literature, and allows us to exhibit many more examples in diverse theories of interest. We first review known examples which are non-intrinsic (i.e., invertible up to gauging), and then describe new examples in Wess-Zumino-Witten models and products of minimal models. For some of these new examples, we show that these continuous non-invertible symmetries are intrinsic if we demand that a certain global symmetry is preserved. The continuous non-invertible symmetries in products of minimal models also allow us to construct new examples of defect conformal manifolds in a single copy of a minimal model. Finally, we comment on continuous non-invertible symmetries in higher dimensions.

Bao-An Li

Nuclear symmetry energy $E_{\mathrm{sym}}(ρ)$ encoding the cost to make nuclear matter more neutron rich has been the most uncertain component of the EOS of dense neutron-rich nucleonic matter. It affects significantly the radii, tidal deformations, cooling rates and frequencies of various oscillation modes of isolated neutron stars as well as the strain amplitude and frequencies of gravitational waves from their mergers, besides its many effects on structures of nuclei as well as the dynamics and observables of their collisions. Siemens (1970s) observed that $E_{\mathrm{sym}}(ρ)$ scales as $(ρ/ρ_0)^{2/3}$ near the saturation density $ρ_0$ of nuclear matter, since both the kinetic part and the potential contribution (quadratic in momentum) exhibit this dependence. The scaling holds if: (1) the nucleon isoscalar potential is quadratic in momentum, and (2) the isovector interaction is weakly density dependent. After examining many empirical evidences and understanding theoretical findings in the literature we conclude that: (1) Siemens' $ρ^{2/3}$ scaling is robust and serves as a valuable benchmark for both nuclear theories and experiments up to $2ρ_0$ but breaks down at higher densities, (2) Experimental and theoretical findings about $E_{\mathrm{sym}}(ρ)$ up to $2ρ_0$ are broadly consistent, but uncertainties remain large for its curvature $K_{\mathrm{sym}}$ and higher-order parameters, (3) Above $2ρ_0$, uncertainties grow due to poorly constrained spin-isospin dependent tensor and three-body forces as well as the resulting nucleon short-range correlations. Looking forward, combining multimessengers from both observations of neutron stars and terrestrial heavy-ion reaction experiments is the most promising path to finally constraining precisely the high-density $E_{\mathrm{sym}}(ρ)$ and the EOS of supradense neutron-rich matter.

Robert Fleischer, Eleftheria Malami, Anders Rehult et al.

Abstract The leptonic decay B s → μ + μ − is both rare and theoretically clean, making it an excellent probe for New Physics searches. Due to its helicity suppression in the Standard Model, this decay is particularly sensitive to new (pseudo)-scalar contributions. We present a new strategy for detecting CP-violating New Physics contributions of this kind, exploiting two observables: A Δ Γ s μμ $$ {\mathcal{A}}_{\Delta {\varGamma}_s}^{\mu \mu} $$ , which is accessible due to the sizeable decay width difference of the B s system, and the mixing-induced CP asymmetry S μμ $$ {\mathcal{S}}_{\mu \mu} $$ . The strategy also uses information from B → K (*) μ + μ − and B s → ϕμ + μ − decays. We find remarkably constrained regions in the A Δ Γ s μμ $$ {\mathcal{A}}_{\Delta {\Gamma}_s}^{\mu \mu} $$ - S μμ $$ {\mathcal{S}}_{\mu \mu} $$ plane that serve as promising targets for future measurements.

Da-Cheng Yan, Yan Yan, Zhou Rui

Abstract In this work, we investigate six helicity amplitudes of the four-body $$B_{(s)} \rightarrow (\pi \pi )(K\bar{K})$$ B ( s ) → ( π π ) ( K K ¯ ) decays via an angular analysis in the perturbative QCD (PQCD) approach. The $$\pi \pi $$ π π invariant mass spectrum is dominated by the vector resonance $$\rho (770)$$ ρ ( 770 ) together with scalar resonance $$f_0(980)$$ f 0 ( 980 ) , while the vector resonance $$\phi (1020)$$ ϕ ( 1020 ) and scalar resonance $$f_0(980)$$ f 0 ( 980 ) are expected to contribute in the $$K\bar{K}$$ K K ¯ invariant mass range. We extract the two-body branching ratios $$\mathcal{B}(B_{(s)}\rightarrow \rho \phi )$$ B ( B ( s ) → ρ ϕ ) from the corresponding four-body decays $$B_{(s)}\rightarrow \rho \phi \rightarrow (\pi \pi )(K \bar{K})$$ B ( s ) → ρ ϕ → ( π π ) ( K K ¯ ) based on the narrow width approximation. The predicted $$\mathcal{B}(B^0_{s}\rightarrow \rho \phi )$$ B ( B s 0 → ρ ϕ ) agrees well with the current experimental data within errors. The longitudinal polarization fractions of the $$B_{(s)}\rightarrow \rho \phi $$ B ( s ) → ρ ϕ decays are found to be as large as $$90\%$$ 90 % , basically consistent with the previous two-body predictions within uncertainties. In addition to the direct CP asymmetries, the triple-product asymmetries (TPAs) originating from the interference among various helicity amplitudes are also presented for the first time. Since the $$B_s^0\rightarrow \rho ^0\phi \rightarrow (\pi ^+\pi ^-)(K^+K^-)$$ B s 0 → ρ 0 ϕ → ( π + π - ) ( K + K - ) decay is induced by both tree and penguin operators, the values of the $$\mathcal{A}^\textrm{CP}_\textrm{dir}$$ A dir CP and $$\mathcal{A}^{1}_{\text {T-true}}$$ A T-true 1 are calculated to be $$(21.8^{+2.7}_{-3.3})\%$$ ( 21 . 8 - 3.3 + 2.7 ) % and $$(-10.23^{+1.73}_{-1.56})\%$$ ( - 10 . 23 - 1.56 + 1.73 ) % respectively. While for pure penguin decays $$B^0\rightarrow \rho ^0\phi \rightarrow (\pi ^+\pi ^-)(K^+K^-)$$ B 0 → ρ 0 ϕ → ( π + π - ) ( K + K - ) and $$B^+\rightarrow \rho ^+\phi \rightarrow (\pi ^+\pi ^0)(K^+K^-)$$ B + → ρ + ϕ → ( π + π 0 ) ( K + K - ) , both the direct CP asymmetries and “true” TPAs are naturally expected to be zero in the standard model (SM) due to the absence of the weak phase difference. The “fake” TPAs requiring no weak phase difference are usually none zero for all considered decay channels. The sizable “fake” $$\mathcal{A}^{1}_{\text {T-fake}}=(-20.92^{+6.26}_{-2.80})\%$$ A T-fake 1 = ( - 20 . 92 - 2.80 + 6.26 ) % of the $$B^0\rightarrow \rho ^0\phi \rightarrow (\pi ^+\pi ^-)(K^+K^-)$$ B 0 → ρ 0 ϕ → ( π + π - ) ( K + K - ) decay is predicted in the PQCD approach, which provides valuable information on the final-state interactions. The above predictions can be tested by the future LHCb and Belle-II experiments.

Sang-Eon Bak, Maulik Parikh, Sudipta Sarkar et al.

Abstract We consider a congruence of null geodesics in the presence of a quantized spacetime metric. The coupling to a quantum metric induces fluctuations in the congruence; we calculate the change in the area of a pencil of geodesics induced by such fluctuations. For the gravitational field in its vacuum state, we find that quantum gravity contributes a correction to the null Raychaudhuri equation which is of the same sign as the classical terms. We thus derive a quantum-gravitational focusing theorem valid for linearized quantum gravity.

Da-Ming Chen, Lin Wang

The spin-torsion theory is a gauge theory approach to gravity that expands upon Einstein’s general relativity (GR) by incorporating the spin of microparticles. In this study, we further develop the spin-torsion theory to examine spherically symmetric and static gravitational systems that involve free-falling macroscopic particles. We posit that the quantum spin of macroscopic matter becomes noteworthy at cosmic scales. We further assume that the Dirac spinor and Dirac equation adequately capture all essential physical characteristics of the particles and their associated processes. A crucial aspect of our approach involves substituting the constant mass in the Dirac equation with a scale function, allowing us to establish a connection between quantum effects and the scale of gravitational systems. This mechanism ensures that the quantum effect of macroscopic matter is scale-dependent and diminishes locally, a phenomenon not observed in microparticles. For any given matter density distribution, our theory predicts an additional quantum term, the quantum potential energy (QPE), within the mass expression. The QPE induces time dilation and distance contraction, and thus mimics a gravitational well. When applied to cosmology, our theory yields a static cosmological model. The QPE serves as a counterpart to the cosmological constant introduced by Einstein to balance gravity in his static cosmological model. The QPE also offers a plausible explanation for the origin of Hubble redshift (traditionally attributed to the universe’s expansion). The predicted luminosity distance–redshift relation aligns remarkably well with SNe Ia data from the cosmological sample of SNe Ia. In the context of galaxies, the QPE functions as the equivalent of dark matter. The predicted circular velocities align well with rotation curve data from the SPARC (Spitzer Photometry and Accurate Rotation Curves database) sample. Importantly, our conclusions in this paper are reached through a conventional approach, with the sole assumption of the quantum effects of macroscopic matter at large scales, without the need for additional modifications or assumptions.

Peter Lalor, Areg Danagoulian

To combat the risk of nuclear smuggling, radiography systems are deployed at ports to scan cargo containers for concealed illicit materials. Dual energy radiography systems enable a rough elemental analysis of cargo containers due to the Z-dependence of photon attenuation, allowing for improved material detection. This work presents our initial experimental findings using a novel approach to predict the atomic number of dual energy images of a loaded cargo container. We consider measurements taken by a Rapiscan Sentry Portal scanner, which is a dual energy betatron-based system used to inspect cargo containers and large vehicles. We demonstrate the ability to accurately fit our semiempirical transparency model to a set of calibration measurements. We then use the calibrated model to reconstruct the atomic number of an unknown material by minimizing the chi-squared error between the measured pixel values and the model predictions. We apply this methodology to two experimental scans of a loaded cargo container. First, we incorporate an image segmentation routine to group clusters of pixels into larger, roughly homogeneous objects. By considering groups of pixels, the subsequent atomic number reconstruction step produces a lower noise result. We demonstrate the ability to accurately reconstruct the atomic number of blocks of steel and high density polyethylene. Furthermore, we are able to identify the presence of two high-Z lead test objects, even when embedded within lower-Z organic shielding. These results demonstrate the significant potential of this methodology to yield improved performance characteristics over existing methods when applied to commercial dual energy systems.

M. Spieker, S. Almaraz-Calderon

Since its foundation in the 1960s, the John D. Fox Superconducting Linear Accelerator Laboratory at Florida State University (FSU) pursued research at the forefront of nuclear science. In this contribution, we present recent highlights from nuclear structure and reaction studies conducted at the John D. Fox Superconducting Linear Accelerator Laboratory, also featuring the general experimental capabilities at the laboratory for particle-$γ$ coincidence experiments. Specifically, we focus on light-ion induced reactions measured with the Super-Enge Split-Pole Spectrograph (SE-SPS) and the CATRiNA neutron detectors, respectively. Some results obtained with the CeBrA demonstrator for particle-$γ$ coincidence experiments at the SE-SPS are presented. A highlight from the first experimental campaigns with the combined CLARION2-TRINITY setup, showing that weak reaction channels can be selected, is discussed as well.

Ren-Tong Guo, Mamutjan Ababekri, Qian Zhao et al.

Vortex $\gamma$ photons, which carry large intrinsic orbital angular momenta (OAM), have significant applications in nuclear, atomic, hadron, particle and astro-physics, but their production remains unclear. In this work, we investigate the generation of such photons from nonlinear Compton scattering of circularly polarized monochromatic lasers on vortex electrons. We develop a quantum radiation theory for ultrarelativistic vortex electrons in lasers by using the harmonics expansion and spin eigenfunctions, which allows us to explore the kinematical characteristics, angular momentum transfer mechanisms, and formation conditions of vortex $\gamma$ photons. The multiphoton absorption of electrons enables the vortex $\gamma$ photons, with fixed polarizations and energies, to exist in mixed states comprised of multiple harmonics. Each harmonic represents a vortex eigenmode and has transverse momentum broadening due to transverse momenta of the vortex electrons. The large topological charges associated with vortex electrons offer the possibility for $\gamma$ photons to carry adjustable OAM quantum numbers from tens to thousands of units, even at moderate laser intensities. $\gamma$ photons with large OAM and transverse coherence length can assist in influencing quantum selection rules and extracting phase of the scattering amplitude in scattering processes.

Q. Yuan

Edward A. Rietman, Brandon Melcher, Alexey Bobrick et al.

We describe the construction of an optical-space, cylindrical black hole induced by high pressure in a dense fluid. Using an approximate analogy between curved spacetime and optics in moving dielectric media, we derive the mass of the black hole thus created. We describe the resulting optical-space using a Bessel beam profile and Snell’s law to understand how total internal reflection produces a cylindrical, optic black hole.

B. Blok, R. Segev, M. Strikman

Abstract We calculate the rate of double parton scattering (DPS) in proton-proton collisions in the framework of the recently proposed hot spot model of the nucleon structure. The resulting rate, especially for the case of three hot spots, is compared with the current experimental data on DPS at the LHC.

Juuso Österman, Philipp Schicho, Aleksi Vuorinen

Abstract Both nonzero temperature and chemical potentials break the Lorentz symmetry present in vacuum quantum field theory by singling out the rest frame of the heat bath. This leads to complications in the application of thermal perturbation theory, including the appearance of novel infrared divergences in loop integrals and an apparent absence of four-dimensional integration-by-parts (IBP) identities, vital for high-order computations. Here, we propose a new strategy that enables the use of IBP techniques in the evaluation of Feynman integrals, in particular vacuum or bubble diagrams, in the limit of vanishing temperature T but nonzero chemical potentials μ. The central elements of the new setup include a contour representation for the temporal momentum integral, the use of a small but nonzero T as an IR regulator, and the systematic application of both temporal and spatial differential operators in the generation of linear relations among the loop integrals of interest. The relations we derive contain novel inhomogeneous terms featuring differentiated Fermi-Dirac distribution functions, which severely complicate calculations at nonzero temperature, but are shown to reduce to solvable lower-dimensional objects as T tends to zero. Pedagogical example computations are kept at the one- and two-loop levels, but the application of the new method to higher-order calculations is discussed in some detail.

Barnabás Pórfy

Measuring quantum-statistical, femtoscopic (including final state interactions) momentum correlations with final state interactions in high-energy nucleus-nucleus collisions reveal the space-time structure of the particle-emitting source created. In this paper, we report NA61/SHINE measurements of femtoscopic correlations of identified pion pairs and describe said correlations based on symmetric Lévy-type sources in Ar+Sc collisions at 150<i>A</i> GeV/<i>c</i>. We investigate the transverse mass dependence of the Lévy-type source parameters and discuss their possible interpretations.

M. Shyti, E. Spahiu

. This paper aims to evaluate the performance of gamma-ray spectrometry in the Institute of Applied Nuclear Physics (IANP), Albania using Proficiency Tests (PTs). Participation in different proficiency tests is an essential tool for the improvement and testing of High Purity Germanium detector (HPGe) performance. The gamma - ray spectrometry laboratory in the last years has participated in different worldwide open proficiency tests organized by International Atomic Energy Agency (IAEA) with satisfactory results. For this paper, we selected the proficiency test organized by the IAEA in 2020 due to the analytical challenge of recognizing radioactive disequilibrium and applying appropriate decay corrections, especially for ingrowing radionuclides of broken natural decay series. The PTs of gamma-ray spectrometry measurements are carried out to improve the laboratory’s ability to measure the radioactivity in the environment and foodstuffs at typical routine levels. The activity concentration of the test samples and the evaluation of the associated uncertainties are the main requirements of the test results. This PT was focused on the determination of anthropogenic and natural radionuclides in water, fish, and simulated aerosol filter samples. For this proficiency test, the Laboratory Sourceless Calibration Software (LabSOCS) is used for simulating the absolute efficiency curve. This paper presents the results and discusses the quality of the gamma spectrometry measurements performed in the IANP. The overall performance evaluation showed that 100 % of all reported results have been acceptable. Thus, the gamma-ray spectrometry using an HPGe detector showed high performance in the determination of anthropogenic and natural radionuclides in water

P. Cortese, G. Dellacasa, L. Ramello et al.

ALICE is a general-purpose heavy-ion experiment designed to study the physics of strongly interacting matter and the quark–gluon plasma in nucleus–nucleus collisions at the LHC. It currently involves more than 900 physicists and senior engineers, from both the nuclear and high-energy physics sectors, from over 90 institutions in about 30 countries.The ALICE detector is designed to cope with the highest particle multiplicities above those anticipated for Pb–Pb collisions (dNch/dy up to 8000) and it will be operational at the start-up of the LHC. In addition to heavy systems, the ALICE Collaboration will study collisions of lower-mass ions, which are a means of varying the energy density, and protons (both pp and pA), which primarily provide reference data for the nucleus–nucleus collisions. In addition, the pp data will allow for a number of genuine pp physics studies.The detailed design of the different detector systems has been laid down in a number of Technical Design Reports issued between mid-1998 and the end of 2004. The experiment is currently under construction and will be ready for data taking with both proton and heavy-ion beams at the start-up of the LHC.Since the comprehensive information on detector and physics performance was last published in the ALICE Technical Proposal in 1996, the detector, as well as simulation, reconstruction and analysis software have undergone significant development. The Physics Performance Report (PPR) provides an updated and comprehensive summary of the performance of the various ALICE subsystems, including updates to the Technical Design Reports, as appropriate.The PPR is divided into two volumes. Volume I, published in 2004 (CERN/LHCC 2003-049, ALICE Collaboration 2004 J. Phys. G: Nucl. Part. Phys. 30 1517–1763), contains in four chapters a short theoretical overview and an extensive reference list concerning the physics topics of interest to ALICE, the experimental conditions at the LHC, a short summary and update of the subsystem designs, and a description of the offline framework and Monte Carlo event generators.The present volume, Volume II, contains the majority of the information relevant to the physics performance in proton–proton, proton–nucleus, and nucleus–nucleus collisions. Following an introductory overview, Chapter 5 describes the combined detector performance and the event reconstruction procedures, based on detailed simulations of the individual subsystems. Chapter 6 describes the analysis and physics reach for a representative sample of physics observables, from global event characteristics to hard processes.

Qi Meng, M. Harada, E. Hiyama et al.

Q. Meng, M. Harada, 3, 4 E. Hiyama, 6, 4, 7 A. Hosaka, 4, 6 and M. Oka 6 Department of Physics, Nanjing University, Nanjing 210093, P.R. China Department of Physics, Nagoya University, Nagoya, 464-8602, Japan Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya 464-8602, Japan Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan Department of Physics, Tohoku University, Sendai 980-8578, Japan Nishina Center for Accelerator-Based Science, RIKEN, Wako 351-0198, Japan Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki 567-0047, Japan (Dated: June 23, 2021)

Juri Fiaschi, Benjamin Fuks, Michael Klasen et al.

Abstract We perform a threshold resummation calculation for the associated production of squarks and electroweakinos at the LHC to the next-to-leading logarithmic (NLL) accuracy. Analytical results for the process-dependent soft anomalous dimension and the hard matching coefficient are presented. The resummed results are matched to fixed-order predictions at next-to-leading order (NLO) in QCD, which are generalised to scenarios with non-universal squark masses and mixings. Numerically, the NLL contributions increase the total NLO cross section by 2% to 6% for squark masses ranging from 1 TeV to 3 TeV, respectively, and they reduce the dependence of the predictions on the factorisation and renormalisation scales from typically ±10% to below ±5%. Our NLO and NLO+NLL calculations have been implemented in the publicly available program Resummino.

A.K. Rao, R.P. Malik

We derive the off-shell nilpotent and absolutely anticommuting (anti-)BRST symmetry transformations for any arbitrary D-dimensional Stückelberg-modified massive Abelian 3-form theory within the framework of augmented version of superfield approach (AVSA) to Becchi-Rouet-Stora-Tyutin (BRST) formalism where, in addition to the horizontality condition (HC), we exploit the theoretical strength of the gauge invariant restriction (GIR) to deduce the proper transformations for the gauge, associated (anti-)ghost fields, auxiliary fields, Stückelberg compensating field, etc. In fact, it is an elegant and delicate combination of HC and GIR (within the ambit of AVSA) that is crucial for all our discussions and derivations. One of the highlights of our present endeavour is the deduction of a new set of (anti-)BRST invariant Curci-Ferrari (CF)-type restrictions which are not found in the massless version of our present theory where only the HC plays an important role in the derivations of all the (anti-)BRST transformations and a very specific set of CF-type restrictions. The alternative ways of the derivation of the full set of the latter, from various theoretical considerations, are also interesting results of our present investigation.

S. Chatterjee, P. P. Bhaduri, S. Chattopadhyay

The yield of $J/ψ$ mesons, produced in proton-nucleus ($p+A$) and nucleus-nucleus ($A+A$) collisions are estimated within a Glauber model ansatz for the upcoming low energy heavy-ion collision experiments at SPS and FAIR. A data driven parametrization is employed to incorporate the effects of Cold Nuclear Matter (CNM) on the $J/ψ$ production cross-section.