The European Physical Journal D最新文献

{"title":"Generalized oscillator strengths and integral cross sections for the valence shell excitations of trichlorofluoromethane studied by fast electron impact","authors":"Muhammad Meesum Bilal,&nbsp;Jin-Feng Chen,&nbsp;Zhi-Wei Nie,&nbsp;Jian-Hui Zhu,&nbsp;Lin-Fan Zhu","doi":"10.1140/epjd/s10053-025-00979-y","DOIUrl":"10.1140/epjd/s10053-025-00979-y","url":null,"abstract":"<p>Oscillator strengths and cross sections of the valence-shell excitations in trichlorofluoromethane CFCl<span>(_{3})</span> are of great importance in plasma etching and monitoring the greenhouse effect. In this work, the valence-shell excitations of CFCl<span>(_{3})</span> have been studied by an angle-resolved electron energy loss spectrometer operated at a collision energy of 1.5 keV with an energy resolution of about 80 meV. Generalized oscillator strengths of the electronically excited states have been determined at an absolute scale by applying the crossed-beam based on the relative flow technique. The behaviors of generalized oscillator strengths of the valence shell excitations of CFCl<span>(_{3})</span> have been analyzed. By extrapolating the generalized oscillator strengths to the zero limit of squared momentum transfer, the optical oscillator strengths have been obtained. The BE-scaled integral cross sections of the valence-shell excitations of CFCl<span>(_{3})</span> have been derived from the excitation thresholds to 5000 eV with the help of BE-scaling method. The present oscillator strengths and cross sections supplement the fundamental database of CFCl<span>(_{3})</span>.\u0000</p><p>Left panel: a schematic diagram of electron energy loss spectrometer. Right panel: the typical electron-energy-loss-spectra of the valence-shell excitations of CFCl<span>(_3)</span> at an incident electron energy of 1500 eV and the scattering angles of (<b>a</b>) 1.5<span>(circ )</span> and (<b>b</b>) 4.5<span>(circ )</span>. The valence excitations and Rydberg transitions are marked as vertical bars. (<b>c</b>) A 2-dimensional map of the GOS density of CFCl<span>(_3)</span> vs. the energy-loss and squared momentum transfer.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radiative energy and mass shifts of quantum cyclotron states","authors":"U. D. Jentschura","doi":"10.1140/epjd/s10053-025-00982-3","DOIUrl":"10.1140/epjd/s10053-025-00982-3","url":null,"abstract":"<p>We discuss relativistic and radiative corrections to the energies of quantum cyclotron states. In particular, it is shown analytically that the leading logarithmic radiative (self-energy) correction to the bound-state energy levels of quantum cyclotron states is state independent and must be interpreted as a magnetic field-dependent correction to the electron’s mass in a Penning trap.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjd/s10053-025-00982-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measuring the 208Tl range of E ≤ 116 keV in silver films","authors":"Y. Ben-Galim,&nbsp;R. Moreh","doi":"10.1140/epjd/s10053-025-00972-5","DOIUrl":"10.1140/epjd/s10053-025-00972-5","url":null,"abstract":"<div><p>In this study, measurements of the effective range of ²⁰⁸Tl ions (<i>E</i> ≤ 116 keV) emanating from the recoil daughters from ²²⁰Rn were carried out. The target used was a set of thin silver films. The amount of the stopped ²⁰⁸Tl ions in each film was determined by measuring the short-lived (~3 m) <span>(beta )</span> activity of ²⁰⁸Tl, where the effective range was found to be 11.8 ± 2.36 µg/cm². This value is in agreement (~20%) with Monte Carlo simulations using SRIM-TRIM software. These simulations also included the attenuation of ²⁰⁸Tl ions caused by the interaction of the ions with the Al sheet holding the ²⁰⁸Tl ion source. After adding the weakened ²⁰⁸Tl source to the simulation, the resulting width of the simulated spectrum was in agreement with experiment (to within 4.5%).</p><h3>Graphical abstract</h3>\u0000<div><figure><div><div><picture><img></picture></div><div><p>Experimental and simulated range histogram of <i>E</i> ≤ 116 keV ²⁰⁸Tl ions in silver films</p></div></div></figure></div></div>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjd/s10053-025-00972-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gas-phase thorium clusters from laser ablation suggest magicity of Th(_{13}^+)","authors":"Paul Fischer,&nbsp;Jonas Stricker,&nbsp;Christoph E. Düllmann,&nbsp;Dennis Renisch,&nbsp;Lutz Schweikhard","doi":"10.1140/epjd/s10053-025-00983-2","DOIUrl":"10.1140/epjd/s10053-025-00983-2","url":null,"abstract":"<p>Laser ablation of a metallic thorium foil produces cationic thorium clusters Th<span>(_n^+)</span> composed of up to <span>(n=15)</span> atoms as well as oxide clusters Th<span>(_n)</span>O<span>(_m^+)</span>. Mass spectra are recorded using a multi-reflection time-of-flight analyzer. Up to <span>(nlesssim 8)</span>, the most abundant species for a given cluster size is the Th<span>(_n)</span>O<span>(_{2n-1}^+)</span> configuration. Notably, pure thorium clusters Th<span>(_n^+)</span> become dominant for <span>(n &gt; rsim 9)</span>. Production drops sharply after Th<span>(_{13}^+)</span> indicating increased relative stability associated with a “magic number” cluster size.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjd/s10053-025-00983-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laboratory constraint on the electric charge of the neutron and the neutrino","authors":"Savely G. Karshenboim","doi":"10.1140/epjd/s10053-025-00964-5","DOIUrl":"10.1140/epjd/s10053-025-00964-5","url":null,"abstract":"<p>We revisit constraints on the value of the electric charge of the neutron and the neutrinos as well as on the electric-charge proton–electron difference <span>(e_p+e_e)</span>. We consider phenomenological constraints based on laboratory study of the electrical neutrality of would-be neutral subatomic, atomic, and molecular species under assumption of the conservation of the electric charge in the <span>(beta )</span> decay that relates the values of <span>(e_p+e_e, e_n, e_nu )</span>. Some of constraints published previously utilized an additional assumption <span>(e_nu =0)</span>, which we do not. We dismiss a cosmological constraint at the level of <span>(10^{-35},e)</span> utilized by Particle Data Group (PDG) in their <i>Review of particle properties</i> Workman et al. (Particle Data Group) (Prog Theor Exp Phys 2022:083C01, 2022) as a controversial one which makes the laboratory constraints on <span>(e_nu )</span> dominant. The phenomenological constraints from the available data of laboratory experiments are obtained as <span>(e_p+e_e=(0.2pm 2.6)times 10^{-21},e)</span>, <span>(e_n=(-0.4pm 1.1)times 10^{-21},e)</span>, and <span>(e_nu =(0.6pm 3.2)times 10^{-21},e)</span>. The ones on <span>(e_p+e_e)</span> and <span>(e_n)</span> are at the same level as the related constraints of PDG but somewhat different because of releasing the value of <span>(e_nu )</span>. Our <span>(e_nu )</span> constraint is several orders of magnitude weaker than the controversial cosmological result dominated in the PDG constraint, but several orders of magnitude stronger than the other individual <span>(e_nu )</span> constraints considered by PDG. We also consider consistency of the phenomenological constraints and the Standard Model (SM). The SM ignores the mass term of the neutrinos and cannot describe the neutrino oscillations which makes it not a complete theory but a part of it. We demonstrate that the condition of the cancellation of the triangle anomalies within the complete theory does not disagree with the phenomenological constraints since different extensions of the SM may produce different additional contributions to the anomalies. A choice of the extension fixes the way how those contributions are organized. In particular, we consider a minimal extension of the SM, where leptons (<span>(nu ,e)</span>) are treated the same ways as quarks, which sets <span>(e_p+e_e=0)</span> and allows for numerical strengthening the constraint on <span>(e_n)</span> and <span>(e_nu )</span>, which is <span>(e_n=-e_nu =(-0.4pm 1.0)times 10^{-21},e)</span>.</p><p>Phenomenological constraint on the value of the electric charge of the neutrino</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjd/s10053-025-00964-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-energy proton beam generation via combined radiation pressure acceleration and laser wakefield acceleration in modulated plasma channels","authors":"Xin Chen,&nbsp;Lu Yang,&nbsp;Xiao-Nan Wang,&nbsp;Li Xiong,&nbsp;Peng-Fan Chen,&nbsp;Hai-Long Zhou,&nbsp;Xiao-Fei Lan,&nbsp;Yong-Sheng Huang,&nbsp;Yang-Fan He","doi":"10.1140/epjd/s10053-025-00977-0","DOIUrl":"10.1140/epjd/s10053-025-00977-0","url":null,"abstract":"<p>High-energy proton beams are essential for fundamental research and applied physics. The combined acceleration mechanism based on radiation pressure acceleration has made great progress in obtaining high-energy protons. However, Rayleigh–Taylor instability (RTI) is still a potential influencing factor that will limit the quality of high-energy proton beams. Different from the previous suppression and neglect of RTI, this paper introduces a parabolic density plasma channel to accelerate protons by virtue of the characteristics of RTI. Three-dimensional Particle-in-cell simulations reveal that this scheme achieves high-energy protons with cut-off energy of 39 <span>(textrm{GeV})</span>, total charge of 0.97 <span>(textrm{nC})</span>, and the emittance of 1.12 <span>(mathrm{{mm}};mathrm{{mrad}})</span> in both the <i>y</i> and <i>z</i> directions. There are locally distributed electrons in the parabolic density plasma channel, and the focusing field around them can effectively focus protons. Compared with the uniform density plasma channel, the parabolic density plasma channel can significantly improve the quality of the proton beam, which could offer significant guidance for the generation and application of high-energy proton beams.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electromagnetic emission of a hollow needle to mesh negative corona and quasi-periodical spark discharge in the air","authors":"Stanislav Pekárek","doi":"10.1140/epjd/s10053-025-00975-2","DOIUrl":"10.1140/epjd/s10053-025-00975-2","url":null,"abstract":"<div><p>We investigated the emission of electromagnetic waves from the stainless-steel hollow needle to mesh corona and quasi-periodical spark discharge without and with airflow through the negative needle electrode in the frequency range below 500 MHz. We showed that there is no electromagnetic waves emission from the pulseless corona discharge. After the discharge transition to the quasi-periodical spark, high-amplitude current pulses correlate with the bursts of electromagnetic radiation. We demonstrated that the spectral distribution of emitted radiation is independent of the discharge voltage, current, and airflow through the needle electrode. We found that the highest peak of the power level of the electric component of emitted waves occurs at the frequency of 15.2 MHz, and the power level of emitted radiation as a function of frequency gradually decreases.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjd/s10053-025-00975-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of the Breit interaction on spin polarization of Auger electrons following electron-impact excitation of Be-like ions","authors":"Y. Li,&nbsp;Z. Q. Tian,&nbsp;J. Q. Wang,&nbsp;C. Z. Dong,&nbsp;S. Fritzsche,&nbsp;Z. W. Wu","doi":"10.1140/epjd/s10053-025-00980-5","DOIUrl":"10.1140/epjd/s10053-025-00980-5","url":null,"abstract":"<p>Spin polarization of Auger electrons emitted from nonradiative Auger decay <span>(1s2s^{2}2p_{1/2},J!=!1 !rightarrow ! 1s^{2}2s,J_{f}!=!1/2)</span> following inner-shell electron-impact excitation from the ground state of highly charged Be-like ions is studied by using the density-matrix theory and the relativistic distorted-wave theory. The question is raised: How does the Breit interaction affect spin polarization of the emitted Auger electrons? Generally, both alignment and intrinsic anisotropy parameters determine the anisotropy of the emitted electrons in this excitation–autoionization process. Here, we calculate and analyze intrinsic spin-polarization parameter for Be-like <span>(hbox {Mg}^{8+})</span>, <span>(hbox {Fe}^{22+})</span>, <span>(hbox {Mo}^{38+})</span>, <span>(hbox {Nd}^{56+})</span>, <span>(hbox {Au}^{75+})</span>, and <span>(hbox {U}^{88+})</span> ions to obtain spin polarization of the Auger electrons. It is found that the Breit interaction hardly contributes to the spin polarization for low-<i>Z</i> Be-like ions such as <span>(hbox {Mg}^{8+})</span>, even at high impact electron energies, whereas for medium- and high-<i>Z</i> ions the situation becomes fairly different. To be specific, the spin polarization becomes nearly zero and almost independent of the emission angle of the Auger electrons owing to the Breit interaction, which becomes more and more prominent with increasing nuclear charge. Moreover, the Breit interaction even changes the direction of the spin polarization vector for high-<i>Z</i> ions especially at low impact energies, for example, for <span>(hbox {U}^{88+})</span> ions at impact energies below the threefold excitation threshold.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 4","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Scattering of electron and positron by methane","authors":"M. Mousumi Khatun,&nbsp;A. K. Fazlul Haque,&nbsp;M. Alfaz Uddin","doi":"10.1140/epjd/s10053-025-00974-3","DOIUrl":"10.1140/epjd/s10053-025-00974-3","url":null,"abstract":"<p>This work provides a comprehensive theoretical investigation of <span>({e^-}-CH_4)</span> and <span>({e^+}-CH_4)</span> scattering systems over a wide range of projectile energies, from 1 eV to 1 MeV. The single scattering independent atom model (IAM) and the screening correction (IAMS), arising from a semi-classical analysis of atomic geometrical overlap, are used within the same framework for the present analysis. A broad spectrum of scattering observable quantities is calculated, such as differential, integrated elastic, momentum transfer, viscosity, inelastic, grand total and total ionization cross sections along with the Sherman function. For this spin-dependent and relativistic scattering study, the Dirac equation is solved using a complex optical potential model (OPM) by partial wave phase-shift analysis to generate the scattering cross-sections data. A satisfactory level of concordance is observed when our computed results are compared to both experimental data and other theoretical calculations available in the literature. The screening corrected independent atom model (IAMS) has been found to produce results with greater accuracy than the IAM.</p><p>Comparison of <img> scattering cross sections (a) DCS in units of <span>(a_0^2/sr)</span> at 90°scattering angle, (b) Sherman function S(θ) at 90°scattering angle, (c) TCS, (d) IECS, (e) TICS and (f) MTCS in units of <span>(a_0^2)</span>. </p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cold source of atomic hydrogen for loading large magnetic traps","authors":"Aleksei Semakin,&nbsp;Janne Ahokas,&nbsp;Otto Hanski,&nbsp;Slava Dvornichenko,&nbsp;Tom Kiilerich,&nbsp;François Nez,&nbsp;Pauline Yzombard,&nbsp;Valery Nesvizhevsky,&nbsp;Eberhard Widmann,&nbsp;Paolo Crivelli,&nbsp;Sergey Vasiliev","doi":"10.1140/epjd/s10053-025-00976-1","DOIUrl":"10.1140/epjd/s10053-025-00976-1","url":null,"abstract":"<p>We present a design and performance tests of an intense source of cold hydrogen atoms for loading large magnetic traps. Our source is based on a cryogenic dissociator of molecular hydrogen at 0.6 K followed by a series of thermal accommodators at 0.5, 0.2 and 0.13 K with inner surfaces covered by a superfluid helium film. All components are thermally anchored to corresponding stages of a dilution refrigerator. The source provides a continuous flux of <span>(7times 10^{13})</span> H atoms/s in a temperature range of 130–200 mK. We have successfully used the source for loading a large Ioffe–Pritchard magnetic trap recently built in our laboratory (Ahokas et al. in Rev Sci Instrum 93(2):023201, 2022). Calorimetric measurements of the atomic recombination heat allow reliable determination of the atomic flux and H gas density in the trap. We have tested the performance of the source and loading of H atoms into the trap at various configurations of the trapping field, reducing the magnetic barrier height to 75<span>(%)</span> and 50<span>(%)</span> of the nominal value of 0.8 T (0.54 K) as well as at the open configuration of the trap at its lower end, when the atoms are in contact with the trapping cell walls covered by a superfluid helium film. In the latter case, raising the trapping cell temperature to 200–250 mK, the low-field seeking atoms at densities exceeding 10<span>(^{11})</span> <span>(hbox {cm}^{-3})</span> can be stored for the time over 10<span>(^3)</span> s, sufficiently long for experiments on precision spectroscopy of cold H gas.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"79 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjd/s10053-025-00976-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}