Study of the p–p–K and p–p–K dynamics using the femtoscopy technique

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 …

The European Physical Journal C

The NA61/SHINE experiment at the CERN Super Proton Synchrotron studies the onset of deconfinement in strongly interacting matter through a beam energy scan of particle production in collisions of nuclei of varied sizes. This paper presents results on inclusive double-differential spectra, transverse momentum and rapidity distributions and mean multiplicities of , , p and produced in collisions at beam momenta of 13A, 19A, 30A, 40A, 75A and 150A . The analysis uses the 10% most central collisions, where the observed forward energy defines centrality. The energy dependence of the / ratios as well as of inverse slope parameters of the transverse mass distributions are placed in between those found in inelastic and central Pb + Pb collisions. The results obtained here establish a system-size dependence of hadron production properties that so far cannot be explained either …

Physical Review Letters

The first measurement of the cross section for incoherent photonuclear production of J/ψ vector mesons as a function of the Mandelstam| t| variable is presented. The measurement was carried out with the ALICE detector at midrapidity,| y|< 0.8, using ultraperipheral collisions of Pb nuclei at a center-of-mass energy per nucleon pair of s NN= 5.02 TeV. This rapidity interval corresponds to a Bjorken-x range (0.3–1.4)× 10− 3. Cross sections are given in five| t| intervals in the range 0.04<| t|< 1 GeV 2 and compared to the predictions by different models. Models that ignore quantum fluctuations of the gluon density in the colliding hadron predict a| t| dependence of the cross section much steeper than in data. The inclusion of such fluctuations in the same models provides a better description of the data.

Journal of Instrumentation

Luminosity determination within the ALICE experiment is based on the measurement, in van der Meer scans, of the cross sections for visible processes involving one or more detectors (visible cross sections). In 2015 and 2018, the Large Hadron Collider provided Pb–Pb collisions at a centre-of-mass energy per nucleon pair of

Physics Letters B

The ALICE Collaboration reports a differential measurement of inclusive jet suppression using pp and Pb–Pb collision data at a center-of-mass energy per nucleon–nucleon collision s NN= 5.02 TeV. Charged-particle jets are reconstructed using the anti-k T algorithm with resolution parameters R= 0.2, 0.3, 0.4, 0.5, and 0.6 in pp collisions and R= 0.2, 0.4, 0.6 in central (0–10%), semi-central (30–50%), and peripheral (60–80%) Pb–Pb collisions. A novel approach based on machine learning is employed to mitigate the influence of jet background. This enables measurements of inclusive jet suppression in new regions of phase space, including down to the lowest jet p T≥ 40 GeV/c at R= 0.6 in central Pb–Pb collisions. This is an important step for discriminating different models of jet quenching in the quark–gluon plasma. The transverse momentum spectra, nuclear modification factors, derived cross section, and …

Journal of Instrumentation

Luminosity determination within the ALICE experiment is based on the measurement, in van der Meer scans, of the cross sections for visible processes involving one or more detectors (visible cross sections). In 2015 and 2018, the Large Hadron Collider provided Pb–Pb collisions at a centre-of-mass energy per nucleon pair of

Physical Review D

Recent measurements of charm-baryon production in hadronic collisions have questioned the universality of charm-quark fragmentation across different collision systems. In this work the fragmentation of charm quarks into charm baryons is probed, by presenting the first measurement of the longitudinal jet momentum fraction carried by Λ c+ baryons, z∥ ch, in hadronic collisions. The results are obtained in proton-proton (p p) collisions at s= 13 TeV at the LHC, with Λ c+ baryons and charged (track-based) jets reconstructed in the transverse momentum intervals of 3≤ p T Λ c+< 15 GeV/c and 7≤ p T jet ch< 15 GeV/c, respectively. The z∥ ch distribution is compared to a measurement of D 0-tagged charged jets in p p collisions as well as to pythia 8 simulations. The data hints that the fragmentation of charm quarks into charm baryons is softer with respect to charm mesons, in the measured kinematic interval, as …

Charged-particle jet yields have been measured in semicentral Pb–Pb collisions at center-of-mass energy per nucleon–nucleon collision

Measurements of the -dependent flow vector fluctuations in Pb-Pb collisions at using azimuthal correlations with the ALICE experiment at the LHC are presented. A four-particle correlation approach [1] is used to quantify the effects of flow angle and magnitude fluctuations separately. This paper extends previous studies to additional centrality intervals and provides measurements of the -dependent flow vector fluctuations at with two-particle correlations. Significant -dependent fluctuations of the flow vector in Pb-Pb collisions are found across different centrality ranges, with the largest fluctuations of up to 15% being present in the 5% most central collisions. In parallel, no evidence of significant -dependent fluctuations of or is found. Additionally, evidence of flow angle and magnitude fluctuations is observed with more than significance in central collisions. These observations in Pb-Pb collisions indicate where the classical picture of hydrodynamic modeling with a common symmetry plane breaks down. This has implications for hard probes at high , which might be biased by -dependent flow angle fluctuations of at least 23% in central collisions. Given the presented results, existing theoretical models should be re-examined to improve our understanding of initial conditions, quark--gluon plasma (QGP) properties, and the dynamic evolution of the created system.

The first measurements of femtoscopic correlations with the particle pair combinations K in pp collisions at TeV at the Large Hadron Collider (LHC) are reported by the ALICE experiment. Using the femtoscopic approach, it is shown that it is possible to study the elusive K particle that has been considered a tetraquark candidate for over forty years. Boson source parameters and final-state interaction parameters are extracted by fitting a model assuming a Gaussian source to the experimentally measured two-particle correlation functions. The final-state interaction is modeled through a resonant scattering amplitude, defined in terms of a mass and a coupling parameter, decaying into a K pair. The extracted mass and Breit-Wigner width, derived from the coupling parameter, of the final-state interaction are found to be consistent with previous measurements of the K. The small value and increasing behavior of the correlation strength with increasing source size support the hypothesis that the K is a four-quark state, i.e. a tetraquark state. This latter trend is also confirmed via a simple geometric model that assumes a tetraquark structure of the K resonance.

Physics Letters B

In this Letter, the first measurement of the inelastic cross section for antitriton–nucleus interactions is reported, covering the momentum range of 0.8≤ p< 2.4 GeV/c. The measurement is carried out using data recorded with the ALICE detector in pp and Pb–Pb collisions at a centre-of-mass energy per nucleon of 13 TeV and 5.02 TeV, respectively. The detector material serves as an absorber for antitriton nuclei. The raw yield of (anti) triton nuclei measured with the ALICE apparatus is compared to the results from detailed ALICE simulations based on the Image 1 toolkit for the propagation of (anti) particles through matter, allowing one to quantify the inelastic interaction probability in the detector material. This analysis complements the measurement of the inelastic cross section of antinuclei up to A= 3 carried out by the ALICE Collaboration, and demonstrates the feasibility of the study of the isospin dependence of …

Physics Letters B

The ALICE Collaboration reports a differential measurement of inclusive jet suppression using pp and Pb–Pb collision data at a center-of-mass energy per nucleon–nucleon collision s NN= 5.02 TeV. Charged-particle jets are reconstructed using the anti-k T algorithm with resolution parameters R= 0.2, 0.3, 0.4, 0.5, and 0.6 in pp collisions and R= 0.2, 0.4, 0.6 in central (0–10%), semi-central (30–50%), and peripheral (60–80%) Pb–Pb collisions. A novel approach based on machine learning is employed to mitigate the influence of jet background. This enables measurements of inclusive jet suppression in new regions of phase space, including down to the lowest jet p T≥ 40 GeV/c at R= 0.6 in central Pb–Pb collisions. This is an important step for discriminating different models of jet quenching in the quark–gluon plasma. The transverse momentum spectra, nuclear modification factors, derived cross section, and …

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 D

The longitudinal and transverse spin transfers to Λ (Λ) hyperons in polarized proton-proton collisions are expected to be sensitive to the helicity and transversity distributions, respectively, of (anti) strange quarks in the proton, and to the corresponding polarized fragmentation functions. We report improved measurements of the longitudinal spin transfer coefficient, D L L, and the transverse spin transfer coefficient, D T T, to Λ and Λin polarized proton-proton collisions at s= 200 GeV by the STAR experiment at RHIC. The dataset includes longitudinally polarized proton-proton collisions with an integrated luminosity of 52 pb− 1, and transversely polarized proton-proton collisions with a similar integrated luminosity. Both datasets have about twice the statistics of previous results and cover a kinematic range of| η Λ (Λ)|< 1.2 and transverse momentum p T, Λ (Λ) up to 8 GeV/c. We also report the first measurements of the …

Physics Letters B

In this Letter, the first measurement of the inelastic cross section for antitriton–nucleus interactions is reported, covering the momentum range of 0.8≤ p< 2.4 GeV/c. The measurement is carried out using data recorded with the ALICE detector in pp and Pb–Pb collisions at a centre-of-mass energy per nucleon of 13 TeV and 5.02 TeV, respectively. The detector material serves as an absorber for antitriton nuclei. The raw yield of (anti) triton nuclei measured with the ALICE apparatus is compared to the results from detailed ALICE simulations based on the Image 1 toolkit for the propagation of (anti) particles through matter, allowing one to quantify the inelastic interaction probability in the detector material. This analysis complements the measurement of the inelastic cross section of antinuclei up to A= 3 carried out by the ALICE Collaboration, and demonstrates the feasibility of the study of the isospin dependence of …

Physical Review D

Recent measurements of charm-baryon production in hadronic collisions have questioned the universality of charm-quark fragmentation across different collision systems. In this work the fragmentation of charm quarks into charm baryons is probed, by presenting the first measurement of the longitudinal jet momentum fraction carried by Λ c+ baryons, z∥ ch, in hadronic collisions. The results are obtained in proton-proton (p p) collisions at s= 13 TeV at the LHC, with Λ c+ baryons and charged (track-based) jets reconstructed in the transverse momentum intervals of 3≤ p T Λ c+< 15 GeV/c and 7≤ p T jet ch< 15 GeV/c, respectively. The z∥ ch distribution is compared to a measurement of D 0-tagged charged jets in p p collisions as well as to pythia 8 simulations. The data hints that the fragmentation of charm quarks into charm baryons is softer with respect to charm mesons, in the measured kinematic interval, as …

Physics Letters B

The first measurements of skewness and kurtosis of mean transverse momentum (< p T>) fluctuations are reported in Pb–Pb collisions at s NN= 5.02 TeV, Xe–Xe collisions at s NN= 5.44 TeV and pp collisions at s= 5.02 TeV using the ALICE detector. The measurements are carried out as a function of system size< d N ch/d η>| η|< 0.5 1/3, using charged particles with transverse momentum (p T) and pseudorapidity (η), in the range 0.2< p T< 3.0 GeV/c and| η|< 0.8, respectively. In Pb–Pb and Xe–Xe collisions, positive skewness is observed in the fluctuations of< p T> for all centralities, which is significantly larger than what would be expected in the scenario of independent particle emission. This positive skewness is considered a crucial consequence of the hydrodynamic evolution of the hot and dense nuclear matter created in heavy-ion collisions. Furthermore, similar observations of positive skewness for minimum …

arXiv

The intense photon fluxes from relativistic nuclei provide an opportunity to study photonuclear interactions in ultraperipheral collisions. The measurement of coherently photoproduced final states in ultraperipheral Pb-Pb collisions at TeV is presented for the first time. The cross section, d/d, times the branching ratio () is found to be mb in the rapidity interval . The invariant mass distribution is not well described with a single Breit-Wigner resonance. The production of two interfering resonances, and , provides a good description of the data. The values of the masses () and widths () of the resonances extracted from the fit are MeV/, MeV/, MeV/ and MeV/, respectively. The measured cross sections times the branching ratios are compared to recent theoretical predictions.

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 …

The critical point of strongly interacting matter is searched for at the CERN SPS by the NA61/SHINE experiment in central Ar+ Sc collisions at 13, 19, 30, 40, and 75 GeV/. The dependence of the second-order scaled factorial moments of proton multiplicity distributions on the number of subdivisions in transverse momentum space is measured. The intermittency analysis uses statistically independent data sets for every subdivision in transverse and cumulative-transverse momentum variables. The results obtained do not indicate the searched intermittent pattern. An upper limit on the fraction of correlated protons and the intermittency index is obtained based on a comparison with the Power-law Model.

The European Physical Journal A

Isospin symmetry is used to fit the precisely known -values of lighter and -emitters and to extrapolate them up to . For the emitters the half-lives of the pure Fermi decays are calculated and compared with experimentally known values, even for the heaviest cases where the experimental uncertainties are still rather large. For the emitters only the Fermi component of the transitions can be predicted, but with the experimental half-lives the ratio of Gamow–Teller to Fermi strength can be determined.

The European Physical Journal A

The average energy and multiplicity of prompt-rays from slow neutron-induced fission of U have been measured using the STEFF spectrometer at the neutron time-of-flight facility n_TOF. The individual responses from 11 NaI scintillators were corrected for multiple-ray interactions, prompt fission neutrons and background counts before being deconvolved to estimate the emitted spectrum of prompt fission-rays. The results give an average-ray energy of 1.71 (5) MeV and multiplicity of 2.66 (18) considering-rays emitted within the energy range 0.8–6.8 MeV. The n_TOF data has a slightly larger and smaller than other recent measurements, however the product of the two is in agreement within quoted uncertainties.

The European Physical Journal A

The MUSE experiment at the Paul Scherrer Institute is measuring elastic lepton-proton scattering cross sections in a four-momentum transfer range from Q2 of approximately 0.002–0.08 GeV2 using positively and negatively charged electrons and muons. The extraction of the Born cross sections from the experimental data requires radiative corrections. Estimates of the instrumental uncertainties in those corrections have been made using the ESEPP event generator. The results depend in particular on the minimum lepton momentum that contributes to the experimental cross section and the fraction of events with hard initial-state radiation that is detected in the MUSE calorimeter and is excluded from the data. These results show that the angular-dependent instrumental uncertainties in radiative corrections to the electron cross section are less than 0.4% and are negligible for the muon cross section.

The European Physical Journal A

The cross section of the Y (n,) reaction has important implications in nuclear astrophysics and for advanced nuclear technology. Given its neutron magic number N= 50 and a consequent small neutron capture cross section, Y represents one of the key nuclides for the stellar s-process. It acts as a bottleneck in the neutron capture chain between the Fe seed and the heavier elements. Moreover, it is located at the overlapping region, where both the weak and main s-process components take place. Y, the only stable yttrium isotope, is also used in innovative nuclear reactors. Neutron capture and transmission measurements were performed at the time-of-flight facilities n_TOF at CERN and GELINA at JRC-Geel. Resonance parameters of individual resonances were extracted from a resonance analysis of the experimental transmission and capture yields, up to a neutron incident energy of 95 keV. Even though a …

The European Physical Journal A

The average energy and multiplicity of prompt-rays from slow neutron-induced fission of U have been measured using the STEFF spectrometer at the neutron time-of-flight facility n_TOF. The individual responses from 11 NaI scintillators were corrected for multiple-ray interactions, prompt fission neutrons and background counts before being deconvolved to estimate the emitted spectrum of prompt fission-rays. The results give an average-ray energy of 1.71 (5) MeV and multiplicity of 2.66 (18) considering-rays emitted within the energy range 0.8–6.8 MeV. The n_TOF data has a slightly larger and smaller than other recent measurements, however the product of the two is in agreement within quoted uncertainties.

The European Physical Journal A

The charged-particle transverse momentum spectra (-spectra) measured by the ALICE collaboration for pp collisions at 7 and 13 TeV have been studied using a thermodynamically consistent form of Tsallis non-extensive statistics. The Tsallis distribution function is fitted to the-spectra and the results are analyzed as a function of final state charged-particle multiplicity for various light flavor and strange particles, such as. At the LHC energies, particles and antiparticles are produced in equal numbers. However, the equality of particle and antiparticle yields at the kinetic freeze-out may imply that they have the same but opposite chemical potential which is not necessarily zero. We use an alternative procedure that makes use of parameter redundancy, by introducing a finite chemical potential at the kinetic freeze-out stage. This article emphasizes the importance of the chemical …

The European Physical Journal A

Production yields of single- hypernuclei from simulated peripheral annihilations of antiprotons after capture on various target nuclei are reported. The initial annihilation process and the production of excited hypernuclei are estimated within the GiBUU transport framework, while their deexcitation process is treated with the ABLA++ code. The yield of excited hypernuclei range from 0.3 % for O to 1.2 % for Xe per annihilation, consistent with previous measurements at LEAR, CERN. The yield of specific ground state hypernuclei after deexcitation reaches up to a few per annihilation. The hypernuclei are produced in strangeness exchange reactions occuring between a nucleon of the target and the kaons originating from the annihilation in 80 % of the cases, while the strangeness pair production in secondary pion-nucleon collision contributes to the remaining 20 %. The simulations indicate that …

The European Physical Journal A

We study the structure of single -hypernuclei using the Hartree–Fock–Bogoliubov method. Finite range Gogny-type forces are used to describe the nucleon–nucleon and -nucleon interactions. Three different -nucleon Gogny forces are built. The unknown parameters of these forces are obtained by fitting the experimental binding energies of the 1s single-particle state in various hypernuclei using the “Simulated Annealing Method”. These forces are then used to calculate the binding energies of the other (1p, 1d, 1f, 1g) single-particle states in the different hypernuclei. The predicted values are found to be in good agreement with the experimental data for the three forces constructed. In addition, we calculate also the root-mean-square radii of ground state orbital, as well as several global properties of the hypernuclei considered such as their ground-state Hartree–Fock–Bogoliubov energy, their pairing …

The European Physical Journal A

The MUSE experiment at the Paul Scherrer Institute is measuring elastic lepton-proton scattering cross sections in a four-momentum transfer range from Q2 of approximately 0.002–0.08 GeV2 using positively and negatively charged electrons and muons. The extraction of the Born cross sections from the experimental data requires radiative corrections. Estimates of the instrumental uncertainties in those corrections have been made using the ESEPP event generator. The results depend in particular on the minimum lepton momentum that contributes to the experimental cross section and the fraction of events with hard initial-state radiation that is detected in the MUSE calorimeter and is excluded from the data. These results show that the angular-dependent instrumental uncertainties in radiative corrections to the electron cross section are less than 0.4% and are negligible for the muon cross section.

The European Physical Journal A

The newly built back-streaming white neutron beam line (Back-n) at China spallation Neutron Source (CSNS) makes a breakthrough for China’s domestic nuclear data measurement, which is pushing nuclear data measurement in China towards higher precision and wider energy range. The neutron flux of the facility was measured at the first beginning since it is an extremely important characterization for the experiment proposal and data analysis. The neutron fluxes under big collimators in end station 1 (ES#1) and end station 2 (ES#2) had been characterized by a fission chamber. In this paper, the first measurement of the neutron flux of Back-n ES#1 with small collimators is reported. The neutron flux from 0.5 eV to 300 MeV was measured by three detectors: a silicon monitor based on a 6LiF sample for the energy range below 200 keV, a fast multi-layer fission ionization chamber for the range from 10 keV to 300 …

The European Physical Journal A

The MUSE experiment at the Paul Scherrer Institute is measuring elastic lepton-proton scattering cross sections in a four-momentum transfer range from Q2 of approximately 0.002–0.08 GeV2 using positively and negatively charged electrons and muons. The extraction of the Born cross sections from the experimental data requires radiative corrections. Estimates of the instrumental uncertainties in those corrections have been made using the ESEPP event generator. The results depend in particular on the minimum lepton momentum that contributes to the experimental cross section and the fraction of events with hard initial-state radiation that is detected in the MUSE calorimeter and is excluded from the data. These results show that the angular-dependent instrumental uncertainties in radiative corrections to the electron cross section are less than 0.4% and are negligible for the muon cross section.

The European Physical Journal A

The stochastic mean-field (SMF) technique beyond the time-dependent-Hartree-Fock approach is used to explore the primary mass yields of quasifission fragments in the reaction at the bombarding energy = 238.5 MeV, reaction at = 237 MeV, and in the reaction at = 151.1 MeV. A statistical de-excitation model, GEMINI++ code, is used for calculating the primary mass yields of fusion–fission fragments after the de-excitation processes of primary products in the same systems. The obtained results are compared with available experimental data. Analysis of SMF and GEMINI++ calculations exhibit a good agreement with the corresponding experimental results, signifying the reliability of our approach in describing the fragment mass yields for the specific reaction systems.

The European Physical Journal A

The newly built back-streaming white neutron beam line (Back-n) at China spallation Neutron Source (CSNS) makes a breakthrough for China’s domestic nuclear data measurement, which is pushing nuclear data measurement in China towards higher precision and wider energy range. The neutron flux of the facility was measured at the first beginning since it is an extremely important characterization for the experiment proposal and data analysis. The neutron fluxes under big collimators in end station 1 (ES#1) and end station 2 (ES#2) had been characterized by a fission chamber. In this paper, the first measurement of the neutron flux of Back-n ES#1 with small collimators is reported. The neutron flux from 0.5 eV to 300 MeV was measured by three detectors: a silicon monitor based on a 6LiF sample for the energy range below 200 keV, a fast multi-layer fission ionization chamber for the range from 10 keV to 300 …

The European Physical Journal A

This paper presents a study of both the elastic and inelastic scattering of a deuteron beam on C at laboratory energy of 18 MeV. The first 10 excited states of the carbon isotope were studied in terms of single-particle and collective models of excitation. Experimental cross sections were obtained by the well-known E–E method. Elastic scattering data were analyzed using an optical model including a nucleus–nucleus interaction potential, while inelastic scattering data were processed using the coupled-channels approach. For the single-particle model, the spectroscopic amplitudes were obtained through calculations of the large-scale shell model with the YSOXT effective NN-potential. A double folding potential was obtained for the d+ C system. A comparison of model calculations with the experimental cross sections was demonstrated. The extracted deformation parameters and calculated spectroscopic information …

The European Physical Journal A

The stochastic mean-field (SMF) technique beyond the time-dependent-Hartree-Fock approach is used to explore the primary mass yields of quasifission fragments in the reaction at the bombarding energy = 238.5 MeV, reaction at = 237 MeV, and in the reaction at = 151.1 MeV. A statistical de-excitation model, GEMINI++ code, is used for calculating the primary mass yields of fusion–fission fragments after the de-excitation processes of primary products in the same systems. The obtained results are compared with available experimental data. Analysis of SMF and GEMINI++ calculations exhibit a good agreement with the corresponding experimental results, signifying the reliability of our approach in describing the fragment mass yields for the specific reaction systems.

The European Physical Journal A

We propose a new measurement of the ratio of positron-proton to electron-proton elastic scattering at DESY. The purpose is to determine the contributions beyond single-photon exchange, which are essential for the Quantum Electrodynamic (QED) description of the most fundamental process in hadronic physics. By utilizing a 20 cm long liquid hydrogen target in conjunction with the extracted beam from the DESY synchrotron, we can achieve an average luminosity of cm s( times the luminosity achieved by OLYMPUS). The proposed two-photon exchange experiment (TPEX) entails a commissioning run at a beam energy of 2 GeV, followed by measurements at 3 GeV, thereby providing new data up to(GeV/c)(twice the range of current measurements). We present and discuss the proposed experimental setup, run plan, and expectations.

The European Physical Journal A

The cross section of the Y (n,) reaction has important implications in nuclear astrophysics and for advanced nuclear technology. Given its neutron magic number N= 50 and a consequent small neutron capture cross section, Y represents one of the key nuclides for the stellar s-process. It acts as a bottleneck in the neutron capture chain between the Fe seed and the heavier elements. Moreover, it is located at the overlapping region, where both the weak and main s-process components take place. Y, the only stable yttrium isotope, is also used in innovative nuclear reactors. Neutron capture and transmission measurements were performed at the time-of-flight facilities n_TOF at CERN and GELINA at JRC-Geel. Resonance parameters of individual resonances were extracted from a resonance analysis of the experimental transmission and capture yields, up to a neutron incident energy of 95 keV. Even though a …

The European Physical Journal A

The cross section of the Y (n,) reaction has important implications in nuclear astrophysics and for advanced nuclear technology. Given its neutron magic number N= 50 and a consequent small neutron capture cross section, Y represents one of the key nuclides for the stellar s-process. It acts as a bottleneck in the neutron capture chain between the Fe seed and the heavier elements. Moreover, it is located at the overlapping region, where both the weak and main s-process components take place. Y, the only stable yttrium isotope, is also used in innovative nuclear reactors. Neutron capture and transmission measurements were performed at the time-of-flight facilities n_TOF at CERN and GELINA at JRC-Geel. Resonance parameters of individual resonances were extracted from a resonance analysis of the experimental transmission and capture yields, up to a neutron incident energy of 95 keV. Even though a …

The European Physical Journal A

The cross section of the Y (n,) reaction has important implications in nuclear astrophysics and for advanced nuclear technology. Given its neutron magic number N= 50 and a consequent small neutron capture cross section, Y represents one of the key nuclides for the stellar s-process. It acts as a bottleneck in the neutron capture chain between the Fe seed and the heavier elements. Moreover, it is located at the overlapping region, where both the weak and main s-process components take place. Y, the only stable yttrium isotope, is also used in innovative nuclear reactors. Neutron capture and transmission measurements were performed at the time-of-flight facilities n_TOF at CERN and GELINA at JRC-Geel. Resonance parameters of individual resonances were extracted from a resonance analysis of the experimental transmission and capture yields, up to a neutron incident energy of 95 keV. Even though a …

The European Physical Journal A

The energies and B(E2) transitions involving the states of the ground- and -bands in thirty transitional and deformed nuclei are calculated using the triaxial projected shell model (TPSM) approach. Systematic good agreement with the existing data substantiates the reliability of the model predictions. The Gamma-rotor version of the collective Bohr Hamiltonian is discussed in order to quantify the classification with respect to the triaxial shape degree of freedom. The pertaining criteria are applied to the TPSM results and the staggering of the energies of the -bands is analyzed in detail. An analog staggering of the intra- is introduced for the first time. The emergence of the staggering phenomena in the transitions is explained in the terms of interactions between the bands.