Measurement of -meson production in collisions at GeV and collisions at GeV

Physical Review C

The measurement of the direct-photon spectrum from Au+ Au collisions at s N N= 200 GeV is presented by the PHENIX Collaboration using the external-photon-conversion technique for 0%–93% central collisions in a transverse-momentum (p T) range of 0.8–10 GeV/c. An excess of direct photons, above prompt-photon production from hard-scattering processes, is observed for p T< 6 GeV/c. Nonprompt direct photons are measured by subtracting the prompt component, which is estimated as N coll-scaled direct photons from p+ p collisions at 200 GeV, from the direct-photon spectrum. Results are obtained for 0.8< p T< 6.0 GeV/c and suggest that the spectrum has an increasing inverse slope from≈ 0.2 to 0.4 GeV/c with increasing p T, which indicates a possible sensitivity of the measurement to photons from earlier stages of the evolution of the collision. In addition, like the direct-photon production, the p T …

After cigarette smoking, Radon (222Rn) inhalation has been regarded the second most significant cause of lung cancer in the US and the world by the U.S. Environmental Protection Agency (EPA) and the World Health Organization (WHO). Radon is an inert noble radioactive gas produced by the Uranium (238U) decay series, specifically by the decay of Radium (226Ra) into Radon. Radon emanates naturally from the soil, particularly in regions rich in granite and slate. Thus far, there have been several controlled laboratory radioactive studies on the dependence of Radon gas emanation on atmospheric physical parameters such as humidity/moisture and temperature. However, there is no clear understanding of the exact emanation and transport process of Radon gas from the soil, and no model defines the dynamics. This paper presents our experience, learning, and modeling results from our extensive research …

The Breit frame provides a natural frame to analyze lepton-proton scattering events. In this reference frame, the parton model hard interactions between a quark and an exchanged boson defines the coordinate system such that the struck quark is back-scattered along the virtual photon momentum direction. In Quantum Chromodynamics (QCD), higher order perturbative or non-perturbative effects can change this picture drastically. As Bjorken- decreases below one half, a rather peculiar event signature is predicted with increasing probability, where no radiation is present in one of the two Breit-frame hemispheres and all emissions are to be found in the other hemisphere. At higher orders in or in the presence of soft QCD effects, predictions of the rate of these events are far from trivial, and that motivates measurements with real data. We report on the first observation of the empty current hemisphere events in electron-proton collisions at the HERA collider using data recorded with the H1 detector at a center-of-mass energy of 319 GeV. The fraction of inclusive neutral-current DIS events with an empty hemisphere is found to be in the selected kinematic region of GeV and inelasticity . The data sample corresponds to an integrated luminosity of 351.1 pb , sufficient to enable differential cross section measurements of these events. The results show an enhanced discriminating power at lower Bjorken- among different Monte Carlo event generator predictions.

Bulletin of the American Physical Society

T04. 00004: Progress on Constraining the Strange Quark Contribution to the Proton Axial Form Factor*

Physical Review C

The measurement of the direct-photon spectrum from Au+ Au collisions at s N N= 200 GeV is presented by the PHENIX Collaboration using the external-photon-conversion technique for 0%–93% central collisions in a transverse-momentum (p T) range of 0.8–10 GeV/c. An excess of direct photons, above prompt-photon production from hard-scattering processes, is observed for p T< 6 GeV/c. Nonprompt direct photons are measured by subtracting the prompt component, which is estimated as N coll-scaled direct photons from p+ p collisions at 200 GeV, from the direct-photon spectrum. Results are obtained for 0.8< p T< 6.0 GeV/c and suggest that the spectrum has an increasing inverse slope from≈ 0.2 to 0.4 GeV/c with increasing p T, which indicates a possible sensitivity of the measurement to photons from earlier stages of the evolution of the collision. In addition, like the direct-photon production, the p T …

This document realized in the framework of the newly established Gaseous Detector R&D Collaboration (DRD1), presents a comprehensive overview of the current state-of-the-art and the challenges related to various gaseous detector concepts and technologies. It is divided into two key sections. The first section, titled" Executive summary", offers a broad perspective on the collaborative scientific organization, characterized by the presence of eight Working Groups (WGs), which serve as the cornerstone for our forthcoming scientific endeavours. This section also contains a detailed inventory of R&D tasks structured into distinct Work Packages (WPs), in alignment with strategic R&D programs that funding agencies may consider supporting. Furthermore, it underlines the critical infrastructures and tools essential for advancing us towards our technological objectives, as outlined in the ECFA R&D roadmap. The second section, titled" Scientific Proposal and R&D Framework," delves deeply into the research work and plans. Each chapter in this section provides a detailed exploration of the activities planned by the WGs, underscoring their pivotal role in shaping our future scientific pursuits. This DRD1 proposal reinforces our unwavering commitment to a collaborative research program that will span the next three years.

arXiv preprint arXiv:2402.10854

We present a global fit of neutral-current elastic (NCE) neutrino-scattering data and parity-violating electron-scattering (PVES) data with the goal of determining the strange quark contribution to the vector and axial form factors of the proton. Previous fits of this form included data from a variety of PVES experiments (PVA4, HAPPEx, G0, SAMPLE) and the NCE neutrino and anti-neutrino data from BNL E734. These fits did not constrain the strangeness contribution to the axial form factor at low very well because there was no NCE data for GeV. Our new fit includes for the first time MiniBooNE NCE data from both neutrino and anti-neutrino scattering; this experiment used a hydrocarbon target and so a model of the neutrino interaction with the carbon nucleus was required. Three different nuclear models have been employed: a relativistic Fermi gas model, the SuperScaling Approximation model, and a spectral function model. We find a tremendous improvement in the constraint of at low compared to previous work, although more data is needed from NCE measurements that focus on exclusive single-proton final states, for example from MicroBooNE.

Physical Review C

The measurement of the direct-photon spectrum from Au+ Au collisions at s N N= 200 GeV is presented by the PHENIX Collaboration using the external-photon-conversion technique for 0%–93% central collisions in a transverse-momentum (p T) range of 0.8–10 GeV/c. An excess of direct photons, above prompt-photon production from hard-scattering processes, is observed for p T< 6 GeV/c. Nonprompt direct photons are measured by subtracting the prompt component, which is estimated as N coll-scaled direct photons from p+ p collisions at 200 GeV, from the direct-photon spectrum. Results are obtained for 0.8< p T< 6.0 GeV/c and suggest that the spectrum has an increasing inverse slope from≈ 0.2 to 0.4 GeV/c with increasing p T, which indicates a possible sensitivity of the measurement to photons from earlier stages of the evolution of the collision. In addition, like the direct-photon production, the p T …

The European Physical Journal C

In this study, we investigate the potential of heavy quarkonia within a magnetized hot QGP medium having finite momentum anisotropy. The phenomenon of inverse magnetic catalysis is introduced into the system, influencing the magnetic field-modified Debye mass and thereby altering the effective quark masses. Concurrently, the impact of momentum anisotropy in the medium is considered that influence the particle distribution in the medium. The thermal decay width and dissociation temperature of quarkonium states, specifically the 1S and 2S states of charmonium and bottomonium, are computed. Our results reveal that both momentum anisotropy and the inverse magnetic catalysis effects play a significant role in modifying the thermal decay width and dissociation temperature of these heavy quarkonia states.

Bulletin of the American Physical Society

The Fermilab muon g-2 experiment recently released an improved measurement of the positive muon magnetic moment anomaly to an accuracy of 0.20 ppm. The anomaly is of interest since it can be predicted with impressive precision and its value is sensitive, via quantum corrections, to the interactions of the muon with the other particles of the Standard Model. Comparison of the measurement result and theoretical predictions thus serves as a powerful test of the completeness of the Standard Model. This comparison has revealed some puzzles, whose resolution might indicate the need for new physics. Details of the Fermilab experiment will be presented, along with a comparison with the theory and future prospects.

Journal of Instrumentation

For accurate determination of particle masses accurate knowledge of the momentum scale of the detectors is crucial. The procedure used to calibrate the momentum scale of the LHCb spectrometer is described and illustrated using the performance obtained with an integrated luminosity of 1.6 fb− 1 collected during 2016 in ???????? running. The procedure uses large samples of ????/????→ ????+ ????− and ????+→ ????/????????+ decays and leads to a relative accuracy of 3× 10− 4 on the momentum scale.

A method is presented to reconstruct charged particles with lifetimes between 10 ps and 10 ns, which considers a combination of their decay products and the partial tracks created by the initial charged particle. Using the Ξ-baryon as a benchmark, the method is demonstrated with simulated events and proton-proton collision data at

Physical Review C

The measurement of the direct-photon spectrum from Au+ Au collisions at s N N= 200 GeV is presented by the PHENIX Collaboration using the external-photon-conversion technique for 0%–93% central collisions in a transverse-momentum (p T) range of 0.8–10 GeV/c. An excess of direct photons, above prompt-photon production from hard-scattering processes, is observed for p T< 6 GeV/c. Nonprompt direct photons are measured by subtracting the prompt component, which is estimated as N coll-scaled direct photons from p+ p collisions at 200 GeV, from the direct-photon spectrum. Results are obtained for 0.8< p T< 6.0 GeV/c and suggest that the spectrum has an increasing inverse slope from≈ 0.2 to 0.4 GeV/c with increasing p T, which indicates a possible sensitivity of the measurement to photons from earlier stages of the evolution of the collision. In addition, like the direct-photon production, the p T …

arXiv preprint arXiv:2203.17058

The invariant yield of electrons from open-heavy-flavor decays for GeV/ at midrapidity in AuAu collisions at = 200 GeV has been measured by the PHENIX experiment at the Relativistic Heavy Ion Collider. A displaced-vertex analysis with the PHENIX silicon-vertex detector enables extraction of the fraction of charm and bottom hadron decays and unfolding of the invariant yield of parent charm and bottom hadrons. The nuclear-modification factors for electrons from charm and bottom hadron decays and heavy-flavor hadrons show both a centrality and a quark-mass dependence, indicating suppression in the quark-gluon plasma produced in these collisions that is medium sized and quark-mass dependent.

Chalcogenide Letters

Solid materials make up a large portion of the physical world around us and much of modern technology. Different solids have different properties and behaviors, so studying them is interesting. Solids can have very different properties, such as hardness, melting point, electrical conductivity, and elasticity. Studying these properties can help us to better understand materials and how they can be used. Many years before the discovery of semiconduction in elements, chalcopyrite itself was known. Various nonlinear frequency mixing interactions and optoelectronic devices have been demonstrated using the chalcopyrites [1, 2]. As a result of their useful design parameters, such as their nonlinear coefficient, appropriate energy band-gap, and birefringence, chalcopyrite crystals

Astroparticle physics

Abstract The Extreme Universe Space Observatory on a Super Pressure Balloon 1 (EUSO-SPB1) was launched in 2017 April from Wanaka, New Zealand. The plan of this mission of opportunity on a NASA super pressure balloon test flight was to circle the southern hemisphere. The primary scientific goal was to make the first observations of ultra-high-energy cosmic-ray extensive air showers (EASs) by looking down on the atmosphere with an ultraviolet (UV) fluorescence telescope from suborbital altitude (33 km). After 12 days and 4 h aloft, the flight was terminated prematurely in the Pacific Ocean. Before the flight, the instrument was tested extensively in the West Desert of Utah, USA, with UV point sources and lasers. The test results indicated that the instrument had sensitivity to EASs of⪆ 3 EeV. Simulations of the telescope system, telescope on time, and realized flight trajectory predicted an observation of about …

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

Excellent particle identification is an essential requirement for the future Electron Ion Collider (EIC) experiment. Particle identification (PID) of the final state hadrons in semi-inclusive deep inelastic scattering allows the measurement of flavor-dependent gluon and quark distributions inside nucleons and nuclei. The EIC PID Consortium (eRD14 Collaboration) was formed in 2015 for identifying and developing PID detectors using ring imaging Cherenkov and ultra-fast time-of-flight techniques for the EIC experiments with broad kinematics coverage. To meet the challenge of limited space in the electron end-cap of EIC experiments, a compact modular ring imaging Cherenkov (mRICH) detector has been developed that provides K/π separation over a momentum coverage of 2 GeV/c to 10 GeV/c, and an e/π separation up to 2.5 GeV/c or more. The mRICH detector consists of an aerogel block, a Fresnel lens …

Disclosed is a reactor thermal management system. A molten salt reactor vessel and a second component (eg, a drain tank) fluidly coupled with the molten salt reactor vessel are configured to receive a flow of a molten salt therewith. The reactor thermal management system includes an internal shield or vessel encompassing the molten salt reactor vessel and the second component, the internal shield or vessel defining a first thermally insulative region therein. The internal shield or vessel is configured to maintain the first thermally insulated region above a melting temperature of the molten salt during operation of the molten salt reactor vessel.

Physical Review C

The measurement of the direct-photon spectrum from Au+ Au collisions at s N N= 200 GeV is presented by the PHENIX Collaboration using the external-photon-conversion technique for 0%–93% central collisions in a transverse-momentum (p T) range of 0.8–10 GeV/c. An excess of direct photons, above prompt-photon production from hard-scattering processes, is observed for p T< 6 GeV/c. Nonprompt direct photons are measured by subtracting the prompt component, which is estimated as N coll-scaled direct photons from p+ p collisions at 200 GeV, from the direct-photon spectrum. Results are obtained for 0.8< p T< 6.0 GeV/c and suggest that the spectrum has an increasing inverse slope from≈ 0.2 to 0.4 GeV/c with increasing p T, which indicates a possible sensitivity of the measurement to photons from earlier stages of the evolution of the collision. In addition, like the direct-photon production, the p T …

arXiv preprint arXiv:2203.17058

The invariant yield of electrons from open-heavy-flavor decays for GeV/ at midrapidity in AuAu collisions at = 200 GeV has been measured by the PHENIX experiment at the Relativistic Heavy Ion Collider. A displaced-vertex analysis with the PHENIX silicon-vertex detector enables extraction of the fraction of charm and bottom hadron decays and unfolding of the invariant yield of parent charm and bottom hadrons. The nuclear-modification factors for electrons from charm and bottom hadron decays and heavy-flavor hadrons show both a centrality and a quark-mass dependence, indicating suppression in the quark-gluon plasma produced in these collisions that is medium sized and quark-mass dependent.

Physical Review C

The yrast and nonyrast states of Te 126 were populated in a fusion-evaporation reaction using a target of Sn 124 and α beam at 31 MeV energy. All the γ− γ coincidences were recorded using the Indian National Gamma Array at the Variable Energy Cyclotron Centre, India, and processed by a digital data-acquisition system. The level scheme was enriched with the addition of 65 new transitions and the identification of five new structures. Spin and parity assignments were made and the subsequent results were interpreted in the framework of the nuclear shell model using the large-scale shell-model code antoine.

Physical Review C

Collective behavior has been observed in high-energy heavy-ion collisions for several decades. Collectivity is driven by the high particle multiplicities that are produced in these collisions. At the CERN Large Hadron Collider (LHC), features of collectivity have also been seen in high-multiplicity proton-proton collisions that can attain particle multiplicities comparable to peripheral Pb-Pb collisions. One of the possible signatures of collective behavior is the decrease of femtoscopic radii extracted from pion and kaon pairs emitted from high-multiplicity collisions with increasing pair transverse momentum. This decrease can be described in terms of an approximate transverse mass scaling. In the present work, femtoscopic analyses are carried out by the ALICE Collaboration on charged pion and kaon pairs produced in p p collisions at s= 13 TeV from the LHC to study possible collectivity in p p collisions. The event-shape …

Physical Review C

Angular distributions of charged particles relative to jet axes are studied in s N N= 200 GeV Au+ Au collisions as a function of the jet orientation with respect to the event plane. This differential study tests the expected path-length dependence of energy loss experienced by a hard-scattered parton as it traverses the hot and dense medium formed in heavy-ion collisions. A second-order event plane is used in the analysis as an experimental estimate of the reaction plane formed by the collision impact parameter and the beam direction. Charged-particle jets with 15< p T, jet< 20 and 20< p T, jet< 40 GeV/c were reconstructed with the anti-k T algorithm with radius parameter setting of R= 0.4 in the 20–50% centrality bin to maximize the initial-state eccentricity of the interaction region. The reaction plane fit method is implemented to remove the flow-modulated background with better precision than prior methods. Yields …

Physical Review C

The first measurements of K*(892) 0 resonance production as a function of charged-particle multiplicity in Xe-Xe collisions at s N N= 5.44 TeV and p p collisions at s= 5.02 TeV using the ALICE detector are presented. The resonance is reconstructed at midrapidity (| y|< 0.5) using the hadronic decay channel K* 0→ K±π∓. Measurements of transverse-momentum integrated yield, mean transverse-momentum, nuclear modification factor of K* 0, and yield ratios of resonance to stable hadron (K* 0/K) are compared across different collision systems (p p, p-Pb, Xe-Xe, and Pb-Pb) at similar collision energies to investigate how the production of K* 0 resonances depends on the size of the system formed in these collisions. The hadronic rescattering effect is found to be independent of the size of colliding systems and mainly driven by the produced charged-particle multiplicity, which is a proxy of the volume of produced …

Physical Review C

The production of η and η′ mesons is studied in proton-proton and proton-lead collisions collected with the LHCb detector. Proton-proton collisions are studied at center-of-mass energies of 5.02 and 13 TeV and proton-lead collisions are studied at a center-of-mass energy per nucleon of 8.16 TeV. The studies are performed in center-of-mass (cm) rapidity regions 2.5< y c. m.< 3.5 (forward rapidity) and− 4.0< y c. m.<− 3.0 (backward rapidity) defined relative to the proton beam direction. The η and η′ production cross sections are measured differentially as a function of transverse momentum for 1.5< p T< 10 GeV and 3< p T< 10 GeV, respectively. The differential cross sections are used to calculate nuclear modification factors. The nuclear modification factors for η and η′ mesons agree at both forward and backward rapidity, showing no significant evidence of mass dependence. The differential cross sections of η …

Physical Review C

Erratum: Angular distribution of γ -rays from neutron-induced compound states of <SUP>140</SUP>La [Phys. Rev. C 97, 034622 (2018)] - NASA/ADS Now on home page ads icon ads Enable full ADS view NASA/ADS Erratum: Angular distribution of γ -rays from neutron-induced compound states of 140 La [Phys. Rev. C 97, 034622 (2018)] Okudaira, T. ; Takada, S. ; Hirota, K. ; Kimura, A. ; Kitaguchi, M. ; Koga, J. ; Nagamoto, K. ; Nakao, T. ; Okada, A. ; Sakai, K. ; Shimizu, HM ; Yamamoto, T. ; Yoshioka, T. Abstract Publication: Physical Review C Pub Date: February 2024 DOI: 10.1103/PhysRevC.109.029903 Bibcode: 2024PhRvC.109b9903O full text sources Publisher | © The SAO/NASA Astrophysics Data System adshelp[at]cfa.harvard.edu The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86A NASA logo Smithsonian logo Resources About ADS ADS …

Physical Review C

The measurement of the direct-photon spectrum from Au+ Au collisions at s N N= 200 GeV is presented by the PHENIX Collaboration using the external-photon-conversion technique for 0%–93% central collisions in a transverse-momentum (p T) range of 0.8–10 GeV/c. An excess of direct photons, above prompt-photon production from hard-scattering processes, is observed for p T< 6 GeV/c. Nonprompt direct photons are measured by subtracting the prompt component, which is estimated as N coll-scaled direct photons from p+ p collisions at 200 GeV, from the direct-photon spectrum. Results are obtained for 0.8< p T< 6.0 GeV/c and suggest that the spectrum has an increasing inverse slope from≈ 0.2 to 0.4 GeV/c with increasing p T, which indicates a possible sensitivity of the measurement to photons from earlier stages of the evolution of the collision. In addition, like the direct-photon production, the p T …

Physical Review C

Two-particle Bose–Einstein momentum correlation functions are studied for charged-hadron pairs in lead-lead collisions at a center-of-mass energy per nucleon pair of s NN= 5.02 TeV. The data sample, containing 4.27× 10 9 minimum bias events corresponding to an integrated luminosity of 0.607 nb− 1, was collected by the CMS experiment in 2018. The experimental results are discussed in terms of a Lévy-type source distribution. The parameters of this distribution are extracted as functions of particle pair average transverse mass and collision centrality. These parameters include the Lévy index or shape parameter α, the Lévy scale parameter R, and the correlation strength parameter λ. The source shape, characterized by α, is found to be neither Cauchy nor Gaussian, implying the need for a full Lévy analysis. Similarly to what was previously found for systems characterized by Gaussian source radii, a …

Physical Review C

The measurement of the direct-photon spectrum from Au+ Au collisions at s N N= 200 GeV is presented by the PHENIX Collaboration using the external-photon-conversion technique for 0%–93% central collisions in a transverse-momentum (p T) range of 0.8–10 GeV/c. An excess of direct photons, above prompt-photon production from hard-scattering processes, is observed for p T< 6 GeV/c. Nonprompt direct photons are measured by subtracting the prompt component, which is estimated as N coll-scaled direct photons from p+ p collisions at 200 GeV, from the direct-photon spectrum. Results are obtained for 0.8< p T< 6.0 GeV/c and suggest that the spectrum has an increasing inverse slope from≈ 0.2 to 0.4 GeV/c with increasing p T, which indicates a possible sensitivity of the measurement to photons from earlier stages of the evolution of the collision. In addition, like the direct-photon production, the p T …

Physical Review C

The production of K*(892)±meson resonance is measured at midrapidity (| y|< 0.5) in Pb− Pb collisions at s N N= 5.02 TeV using the ALICE detector at the CERN Large Hadron Collider. The resonance is reconstructed via its hadronic decay channel K*(892)±→ K S 0 π±. The transverse momentum distributions are obtained for various centrality intervals in the p T range of 0.4− 16 GeV/c. Measurements of integrated yields, mean transverse momenta, and particle yield ratios are reported and found to be consistent with previous ALICE measurements for K*(892) 0 within uncertainties. The p T-integrated yield ratio 2 K*(892)±/(K++ K−) in central Pb− Pb collisions shows a significant suppression at a level of 9.3 σ relative to p p collisions. Thermal model calculations result in an overprediction of the particle yield ratio. Although both hadron resonance gas in partial chemical equilibrium (HRG-PCE) and music+ smash …

Physical Review C

Utilizing rapidity-dependent measurements to map the QCD phase diagram provides a complementary approach to traditional beam-energy-dependent measurements around midrapidity. The changing nature of thermodynamic properties of QCD matter along the beam axis in heavy-ion collisions at low collision energies both motivates and poses challenges for this method. In this study, we derive the analytical cumulant-generating function for subsystems within distinct rapidity windows, while accounting for global net-baryon charge conservation of the full system. Rapidity-dependent net-baryon cumulants are then calculated for a system exhibiting inhomogeneity along the beam axis, and their sensitivity to finite acceptances through changing rapidity bin widths is explored. We highlight the nontrivial behaviors exhibited by these cumulants, underscoring their importance in establishing a noncritical baseline for …

Physical Review C

High spin states of K 40 populated through the Al 27 (F 19, α n p) K 40 reaction at 68 MeV beam energy were studied using the Indian National Gamma Array (INGA) facility. Six new levels and fourteen new transitions were added to the existing level scheme. The spins and parities of most of the levels were assigned, modified, or confirmed from R DCO, R ADO, and linear polarization measurements. The multipole mixing ratios (δ) for most of the transitions were measured. Large-basis shell-model calculations were performed to understand the microscopic origin of the levels. Different particle restrictions in s d and p f shell orbitals were used to explain the experimental results.

Physical Review C

The production of K*(892)±meson resonance is measured at midrapidity (| y|< 0.5) in Pb− Pb collisions at s N N= 5.02 TeV using the ALICE detector at the CERN Large Hadron Collider. The resonance is reconstructed via its hadronic decay channel K*(892)±→ K S 0 π±. The transverse momentum distributions are obtained for various centrality intervals in the p T range of 0.4− 16 GeV/c. Measurements of integrated yields, mean transverse momenta, and particle yield ratios are reported and found to be consistent with previous ALICE measurements for K*(892) 0 within uncertainties. The p T-integrated yield ratio 2 K*(892)±/(K++ K−) in central Pb− Pb collisions shows a significant suppression at a level of 9.3 σ relative to p p collisions. Thermal model calculations result in an overprediction of the particle yield ratio. Although both hadron resonance gas in partial chemical equilibrium (HRG-PCE) and music+ smash …

Physical Review C

Natural indium targets were exposed to high-energy bremsstrahlung radiation, from 9 MeV to 23 MeV. Using the measured γ spectra, the yield ratio of In 113 m and In 115 m was determined. It was checked to what extent the measured values of the yield ratio can be reproduced using the existing experimental data of cross sections of relevant photonuclear reactions, as well as cross sections obtained by talys calculations. The measured reaction yield ratio was used to reconstruct the energy differential cross section of In 115 (γ, 2 n) In 113 m using the unfolding procedure.

Physical Review C

Two-particle Bose–Einstein momentum correlation functions are studied for charged-hadron pairs in lead-lead collisions at a center-of-mass energy per nucleon pair of s NN= 5.02 TeV. The data sample, containing 4.27× 10 9 minimum bias events corresponding to an integrated luminosity of 0.607 nb− 1, was collected by the CMS experiment in 2018. The experimental results are discussed in terms of a Lévy-type source distribution. The parameters of this distribution are extracted as functions of particle pair average transverse mass and collision centrality. These parameters include the Lévy index or shape parameter α, the Lévy scale parameter R, and the correlation strength parameter λ. The source shape, characterized by α, is found to be neither Cauchy nor Gaussian, implying the need for a full Lévy analysis. Similarly to what was previously found for systems characterized by Gaussian source radii, a …

Physical Review C

Neutron transmission experiments can offer a new type of highly sensitive search for time-reversal invariance violating (TRIV) effects in nucleon-nucleon interactions via the same enhancement mechanism observed for large parity violating (PV) effects in neutron-induced compound nuclear processes. In these compound processes, the TRIV cross section is given as the product of the PV cross section, a spin factor κ, and a ratio of TRIV and PV matrix elements. We determined κ to be 0.59±0.05 for La 139+ n using both (n, γ) spectroscopy and (n ⃗+ 139 La ⃗) transmission. This result quantifies for the first time the high sensitivity of the La 139 0.75-eV p-wave resonance in a future search for effects of P-odd/T-odd interactions in (n ⃗+ 139 La ⃗) forward transmission.

Physical Review C

Two-particle Bose–Einstein momentum correlation functions are studied for charged-hadron pairs in lead-lead collisions at a center-of-mass energy per nucleon pair of s NN= 5.02 TeV. The data sample, containing 4.27× 10 9 minimum bias events corresponding to an integrated luminosity of 0.607 nb− 1, was collected by the CMS experiment in 2018. The experimental results are discussed in terms of a Lévy-type source distribution. The parameters of this distribution are extracted as functions of particle pair average transverse mass and collision centrality. These parameters include the Lévy index or shape parameter α, the Lévy scale parameter R, and the correlation strength parameter λ. The source shape, characterized by α, is found to be neither Cauchy nor Gaussian, implying the need for a full Lévy analysis. Similarly to what was previously found for systems characterized by Gaussian source radii, a …

Physical Review C

A measurement of the Mo 94 (p, γ) Tc 95 cross section was performed. The cross section was measured in the energy range E c. m.= 1.5–4.5 MeV, spanning essentially the entirety of the Gamow window relevant to the astrophysical γ process. The γ-summing technique was used to analyze the data. At lower energies the sum peak overlapped with peaks from the reaction F 19 (p, α γ) O 16, so a new analysis method was developed to filter out the contamination from the this reaction. The measured cross section values were compared to the non-smoker database. The measured cross sections show enhanced resonancelike features at low energies, which are not predicted in the non-smoker code. The effects of this new measurement on the reaction rate were examined. It was found that there is a significant enhancement at lower temperatures in the (p, γ) reaction rate due to the enhancements found in the cross …

Physical Review C

The complete and incomplete fusion cross sections for the Li 7+ Tl 205 reaction were measured at near barrier energies by the online characteristic γ-ray detection technique. The complete fusion (CF) cross sections at energies above the Coulomb barrier were found to be suppressed by∼ 26% compared to the coupled channel calculations. Reduced fusion cross sections for the present system at energies normalized to the Coulomb barrier were also found to be systematically lower than those with strongly bound projectiles forming a similar compound nucleus. The suppression observed in CF cross sections is found to be commensurate with the measured total incomplete fusion (ICF) cross sections. In the ICF cross sections, t-capture is found to be dominant than α-capture at all the measured energies. The systematic study of available CF, ICF, and total fusion data with the Li 7 projectile is performed.

Physical Review C

Project 8 has developed a novel technique, cyclotron radiation emission spectroscopy (CRES), for direct neutrino mass measurements. A CRES-based experiment on the beta spectrum of tritium has been carried out in a small-volume apparatus. We provide a detailed account of the experiment, focusing on systematic effects and analysis techniques. In a Bayesian (frequentist) analysis, we measure the tritium endpoint as 18 553− 19+ 18 (18 548− 19+ 19) eV and set upper limits of 155 (152) eV (90% CL) on the neutrino mass. No background events are observed beyond the endpoint in 82 days of running. We also demonstrate an energy resolution of 1.66±0.19 eV in a resolution-optimized magnetic trap configuration by measuring Kr 83 m 17.8-keV internal-conversion electrons. These measurements establish CRES as a low-background, high-resolution technique with the potential to advance neutrino mass …