Pub Date : 2025-07-17DOI: 10.1016/j.ppnp.2025.104187
Kerstin Hoepfner
The luminosity frontier in particle physics, in particular the high-luminosity LHC, poses a new level of challenges for the detection of muons. In consequence, muon systems had to evolve into large-scale tracking systems with high spatial and time resolution. Especially the forward regions of the LHC experiments ATLAS and CMS will be challenged by high particle rates and the resulting irradiation, while they need to identify and efficiently trigger the muons from signal events. A new type of gaseous detectors – micro-pattern gas detectors – plays a crucial role in the quest of meeting these goals. This next generation of muon systems had to overcome several technological challenges, like mass production of large-area detectors and high-voltage stability. Two technologies of micropattern gas detectors were identified for the upgrades of the muon forward systems of ATLAS and CMS. This article focuses on their development, implementation and performance. At the end, examples of promising R&D for further developments of future muon systems are summarized.
{"title":"Precise muon detection with novel micropattern gaseous detectors","authors":"Kerstin Hoepfner","doi":"10.1016/j.ppnp.2025.104187","DOIUrl":"10.1016/j.ppnp.2025.104187","url":null,"abstract":"<div><div>The luminosity frontier in particle physics, in particular the high-luminosity LHC, poses a new level of challenges for the detection of muons. In consequence, muon systems had to evolve into large-scale tracking systems with high spatial and time resolution. Especially the forward regions of the LHC experiments ATLAS and CMS will be challenged by high particle rates and the resulting irradiation, while they need to identify and efficiently trigger the muons from signal events. A new type of gaseous detectors – micro-pattern gas detectors – plays a crucial role in the quest of meeting these goals. This next generation of muon systems had to overcome several technological challenges, like mass production of large-area detectors and high-voltage stability. Two technologies of micropattern gas detectors were identified for the upgrades of the muon forward systems of ATLAS and CMS. This article focuses on their development, implementation and performance. At the end, examples of promising R&D for further developments of future muon systems are summarized.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"145 ","pages":"Article 104187"},"PeriodicalIF":14.5,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144664996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2025-07-14DOI: 10.1016/j.ppnp.2025.104188
Wei Nan (南巍) , Bing Guo (郭冰) , Jie Chen (陈洁) , Baoqun Cui (崔保群) , Wei Fu (付伟) , Xianlu Jia (贾先禄) , Chaoxin Kan (阚朝新) , Jiayinghao Li (李家英豪) , Yunju Li (李云居) , Chengjian Lin (林承键) , Yihui Liu (刘亦晖) , Nanru Ma (马南茹) , Zhaohua Peng (彭朝华) , Yangping Shen (谌阳平) , Guofang Song (宋国芳) , Jun Su (苏俊) , Bing Tang (唐兵) , Haorui Wang (王浩睿) , Youbao Wang (王友宝) , Lei Yang (杨磊) , Weiping Liu (柳卫平)
The Beijing Radioactive Ion-beam Facility (BRIF), based on the Isotope Separation On-Line (ISOL) technique, consists of a 100 MeV proton cyclotron as the driving accelerator, a two-stage ISOL system for ion separation, a 13-MV tandem accelerator for post-acceleration, a superconducting linac for further boosting beam energies. It is capable of providing ISOL beams in the energy range from 60 to 300 keV, and post-accelerated beams in the energy range from 3 to 10 MeV/u for nuclei with mass numbers of 80. For nuclei with up to 170, energies are still able to reach 3 MeV/u. This facility offers opportunities to address key questions of current interest in nuclear astrophysics, nuclear structure and reactions of unstable nuclei. In this review we present a comprehensive introduction to the BRIF and the typical experimental instruments installed on it, and then summarize current experimental results on unstable Na and Rb isotopes and future plan for development of the BRIF to improve its performance.
{"title":"Nuclear physics at BRIF","authors":"Wei Nan (南巍) , Bing Guo (郭冰) , Jie Chen (陈洁) , Baoqun Cui (崔保群) , Wei Fu (付伟) , Xianlu Jia (贾先禄) , Chaoxin Kan (阚朝新) , Jiayinghao Li (李家英豪) , Yunju Li (李云居) , Chengjian Lin (林承键) , Yihui Liu (刘亦晖) , Nanru Ma (马南茹) , Zhaohua Peng (彭朝华) , Yangping Shen (谌阳平) , Guofang Song (宋国芳) , Jun Su (苏俊) , Bing Tang (唐兵) , Haorui Wang (王浩睿) , Youbao Wang (王友宝) , Lei Yang (杨磊) , Weiping Liu (柳卫平)","doi":"10.1016/j.ppnp.2025.104188","DOIUrl":"10.1016/j.ppnp.2025.104188","url":null,"abstract":"<div><div>The Beijing Radioactive Ion-beam Facility (BRIF), based on the Isotope Separation On-Line (ISOL) technique, consists of a 100 MeV proton cyclotron as the driving accelerator, a two-stage ISOL system for ion separation, a 13-MV tandem accelerator for post-acceleration, a superconducting linac for further boosting beam energies. It is capable of providing ISOL beams in the energy range from 60 to 300 keV, and post-accelerated beams in the energy range from 3 to 10 MeV/u for nuclei with mass numbers of <span><math><mi>A</mi></math></span> <span><math><mo><</mo></math></span> 80. For nuclei with <span><math><mi>A</mi></math></span> up to 170, energies are still able to reach 3 MeV/u. This facility offers opportunities to address key questions of current interest in nuclear astrophysics, nuclear structure and reactions of unstable nuclei. In this review we present a comprehensive introduction to the BRIF and the typical experimental instruments installed on it, and then summarize current experimental results on unstable Na and Rb isotopes and future plan for development of the BRIF to improve its performance.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"145 ","pages":"Article 104188"},"PeriodicalIF":14.5,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144665021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2025-06-23DOI: 10.1016/j.ppnp.2025.104186
M.N. Ferreira , J. Papavassiliou
It has long been argued that the action of the Schwinger mechanism in the gauge sector of Quantum Chromodynamics leads to the generation of a gluon mass scale. Within this scenario, the analytic structure of the fundamental vertices is modified by the creation of scalar colored excitations with vanishing mass. In the limit of zero momentum transfer, these terms act as massless poles, providing the required conditions for the infrared stabilization of the gluon propagator, and producing a characteristic displacement to the associated Ward identities. In this article we offer an extensive overview of the salient notions and techniques underlying this dynamical picture. We place particular emphasis on recent developments related to the exact renormalization of the mass, the nonlinear nature of the pole equation, and the key role played by the Fredholm alternative theorem.
{"title":"Gluon mass scale through the Schwinger mechanism","authors":"M.N. Ferreira , J. Papavassiliou","doi":"10.1016/j.ppnp.2025.104186","DOIUrl":"10.1016/j.ppnp.2025.104186","url":null,"abstract":"<div><div>It has long been argued that the action of the Schwinger mechanism in the gauge sector of Quantum Chromodynamics leads to the generation of a gluon mass scale. Within this scenario, the analytic structure of the fundamental vertices is modified by the creation of scalar colored excitations with vanishing mass. In the limit of zero momentum transfer, these terms act as massless poles, providing the required conditions for the infrared stabilization of the gluon propagator, and producing a characteristic displacement to the associated Ward identities. In this article we offer an extensive overview of the salient notions and techniques underlying this dynamical picture. We place particular emphasis on recent developments related to the exact renormalization of the mass, the nonlinear nature of the pole equation, and the key role played by the Fredholm alternative theorem.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"144 ","pages":"Article 104186"},"PeriodicalIF":14.5,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2025-05-26DOI: 10.1016/j.ppnp.2025.104177
Huey-Wen Lin
The strong force which binds hadrons is described by the theory of quantum chromodynamics (QCD). Determining the character and manifestations of QCD is one of the most important and challenging outstanding issues necessary for a comprehensive understanding of the structure of hadrons. Within the context of the QCD parton picture, the parton distribution functions (PDFs) have been remarkably successful in describing a wide variety of processes. However, these PDFs have generally been confined to the description of collinear partons within the hadron. New experiments and facilities provide the opportunity to additionally explore the three-dimensional structure of hadrons, which can be described by generalized parton distributions (GPDs), for example.
In recent years, a breakthrough was made in calculating the Bjorken- dependence of PDFs in lattice QCD by using large-momentum effective theory (LaMET) and other similar frameworks. The breakthrough has led to the emergence and rapid development of direct calculations of Bjorken--dependent structure. In this review article, we show some of the recent progress made in lattice QCD in PDFs and GPDs and discuss future challenges.
{"title":"Mapping parton distributions of hadrons with lattice QCD","authors":"Huey-Wen Lin","doi":"10.1016/j.ppnp.2025.104177","DOIUrl":"10.1016/j.ppnp.2025.104177","url":null,"abstract":"<div><div>The strong force which binds hadrons is described by the theory of quantum chromodynamics (QCD). Determining the character and manifestations of QCD is one of the most important and challenging outstanding issues necessary for a comprehensive understanding of the structure of hadrons. Within the context of the QCD parton picture, the parton distribution functions (PDFs) have been remarkably successful in describing a wide variety of processes. However, these PDFs have generally been confined to the description of collinear partons within the hadron. New experiments and facilities provide the opportunity to additionally explore the three-dimensional structure of hadrons, which can be described by generalized parton distributions (GPDs), for example.</div><div>In recent years, a breakthrough was made in calculating the Bjorken-<span><math><mi>x</mi></math></span> dependence of PDFs in lattice QCD by using large-momentum effective theory (LaMET) and other similar frameworks. The breakthrough has led to the emergence and rapid development of direct calculations of Bjorken-<span><math><mi>x</mi></math></span>-dependent structure. In this review article, we show some of the recent progress made in lattice QCD in PDFs and GPDs and discuss future challenges.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"144 ","pages":"Article 104177"},"PeriodicalIF":14.5,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144169879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2025-05-01DOI: 10.1016/j.ppnp.2025.104176
Francesco Giacosa , Péter Kovács , Shahriyar Jafarzade
<div><div>The extended Linear Sigma Model (eLSM) is a hadronic model based on the global symmetries of QCD and the corresponding explicit, anomalous, and spontaneous breaking patterns. In its basic three-flavor form, its mesonic part contains the dilaton/glueball as well as the nonets of pseudoscalar, scalar, vector, and axial–vector mesons, thus chiral symmetry is linearly realized. In the chiral limit and neglecting the chiral anomaly, only one term – within the dilaton potential – breaks dilatation invariance, and all terms are chirally symmetric. Spontaneous symmetry breaking is implemented by a generalization of the Mexican-hat potential, with explicit symmetry breaking responsible for its tilting. The overall mesonic phenomenology up to <span><math><mrow><mo>∼</mo><mn>2</mn></mrow></math></span> GeV is in agreement with the PDG compilation of masses and partial and total decay widths. The eLSM was enlarged in a straightforward way to include other conventional quark–antiquark nonets (pseudovector and orbitally excited vector mesons, tensor and axial-tensor mesons, radially excited (pseudo)scalar mesons, etc.), as well as two nonets of hybrid mesons, the lightest one with exotic quantum numbers <span><math><mrow><msup><mrow><mi>J</mi></mrow><mrow><mi>P</mi><mi>C</mi></mrow></msup><mo>=</mo><msup><mrow><mn>1</mn></mrow><mrow><mo>−</mo><mo>+</mo></mrow></msup></mrow></math></span> not allowed for <span><math><mrow><mover><mrow><mi>q</mi></mrow><mrow><mo>̄</mo></mrow></mover><mi>q</mi></mrow></math></span> objects, such as the resonance <span><math><mrow><msub><mrow><mi>π</mi></mrow><mrow><mn>1</mn></mrow></msub><mrow><mo>(</mo><mn>1600</mn><mo>)</mo></mrow></mrow></math></span> and the recently discovered <span><math><mrow><msub><mrow><mi>η</mi></mrow><mrow><mn>1</mn></mrow></msub><mrow><mo>(</mo><mn>1855</mn><mo>)</mo></mrow></mrow></math></span>. In doing so, different types of chiral multiplets are introduced: heterochiral and homochiral multiplets, which differ in the way they transform under chiral transformations. Moreover, besides the scalar glueball that is present from the beginning as dilaton, other glueballs, the tensor, the pseudoscalar and the vector glueballs were coupled to the eLSM: the scalar resonance <span><math><mrow><msub><mrow><mi>f</mi></mrow><mrow><mn>0</mn></mrow></msub><mrow><mo>(</mo><mn>1710</mn><mo>)</mo></mrow></mrow></math></span> turns out to be mostly gluonic, the tensor glueball couples strongly to vector mesons, and the pseudoscalar glueball couples sizably to <span><math><mrow><mi>π</mi><mi>π</mi><msup><mrow><mi>η</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></math></span> and can be assigned to <span><math><mrow><mi>X</mi><mrow><mo>(</mo><mn>2370</mn><mo>)</mo></mrow></mrow></math></span> or <span><math><mrow><mi>X</mi><mrow><mo>(</mo><mn>2600</mn><mo>)</mo></mrow></mrow></math></span>. In all cases above, masses and decays can be analyzed allowing for a better understanding of both conventional and non-
{"title":"Ordinary and exotic mesons in the extended Linear Sigma Model","authors":"Francesco Giacosa , Péter Kovács , Shahriyar Jafarzade","doi":"10.1016/j.ppnp.2025.104176","DOIUrl":"10.1016/j.ppnp.2025.104176","url":null,"abstract":"<div><div>The extended Linear Sigma Model (eLSM) is a hadronic model based on the global symmetries of QCD and the corresponding explicit, anomalous, and spontaneous breaking patterns. In its basic three-flavor form, its mesonic part contains the dilaton/glueball as well as the nonets of pseudoscalar, scalar, vector, and axial–vector mesons, thus chiral symmetry is linearly realized. In the chiral limit and neglecting the chiral anomaly, only one term – within the dilaton potential – breaks dilatation invariance, and all terms are chirally symmetric. Spontaneous symmetry breaking is implemented by a generalization of the Mexican-hat potential, with explicit symmetry breaking responsible for its tilting. The overall mesonic phenomenology up to <span><math><mrow><mo>∼</mo><mn>2</mn></mrow></math></span> GeV is in agreement with the PDG compilation of masses and partial and total decay widths. The eLSM was enlarged in a straightforward way to include other conventional quark–antiquark nonets (pseudovector and orbitally excited vector mesons, tensor and axial-tensor mesons, radially excited (pseudo)scalar mesons, etc.), as well as two nonets of hybrid mesons, the lightest one with exotic quantum numbers <span><math><mrow><msup><mrow><mi>J</mi></mrow><mrow><mi>P</mi><mi>C</mi></mrow></msup><mo>=</mo><msup><mrow><mn>1</mn></mrow><mrow><mo>−</mo><mo>+</mo></mrow></msup></mrow></math></span> not allowed for <span><math><mrow><mover><mrow><mi>q</mi></mrow><mrow><mo>̄</mo></mrow></mover><mi>q</mi></mrow></math></span> objects, such as the resonance <span><math><mrow><msub><mrow><mi>π</mi></mrow><mrow><mn>1</mn></mrow></msub><mrow><mo>(</mo><mn>1600</mn><mo>)</mo></mrow></mrow></math></span> and the recently discovered <span><math><mrow><msub><mrow><mi>η</mi></mrow><mrow><mn>1</mn></mrow></msub><mrow><mo>(</mo><mn>1855</mn><mo>)</mo></mrow></mrow></math></span>. In doing so, different types of chiral multiplets are introduced: heterochiral and homochiral multiplets, which differ in the way they transform under chiral transformations. Moreover, besides the scalar glueball that is present from the beginning as dilaton, other glueballs, the tensor, the pseudoscalar and the vector glueballs were coupled to the eLSM: the scalar resonance <span><math><mrow><msub><mrow><mi>f</mi></mrow><mrow><mn>0</mn></mrow></msub><mrow><mo>(</mo><mn>1710</mn><mo>)</mo></mrow></mrow></math></span> turns out to be mostly gluonic, the tensor glueball couples strongly to vector mesons, and the pseudoscalar glueball couples sizably to <span><math><mrow><mi>π</mi><mi>π</mi><msup><mrow><mi>η</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></math></span> and can be assigned to <span><math><mrow><mi>X</mi><mrow><mo>(</mo><mn>2370</mn><mo>)</mo></mrow></mrow></math></span> or <span><math><mrow><mi>X</mi><mrow><mo>(</mo><mn>2600</mn><mo>)</mo></mrow></mrow></math></span>. In all cases above, masses and decays can be analyzed allowing for a better understanding of both conventional and non-","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"143 ","pages":"Article 104176"},"PeriodicalIF":14.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2025-04-24DOI: 10.1016/j.ppnp.2025.104175
Gökçe Başar
The study of thermal fluctuations in relativistic hydrodynamics has led to numerous important developments in the last decade. We present a bird’s eye view of the recent advances on the theory of fluctuations on three fronts; stochastic hydrodynamics, hydro-kinetics where fluctuations are included as additional modes that satisfy deterministic evolution equations, and effective field theory formulation of relativistic hydrodynamics. We compare and contrast these different but complimentary frameworks and highlight various recent progresses in each of them.
{"title":"Recent developments in relativistic hydrodynamic fluctuations","authors":"Gökçe Başar","doi":"10.1016/j.ppnp.2025.104175","DOIUrl":"10.1016/j.ppnp.2025.104175","url":null,"abstract":"<div><div>The study of thermal fluctuations in relativistic hydrodynamics has led to numerous important developments in the last decade. We present a bird’s eye view of the recent advances on the theory of fluctuations on three fronts; stochastic hydrodynamics, hydro-kinetics where fluctuations are included as additional modes that satisfy deterministic evolution equations, and effective field theory formulation of relativistic hydrodynamics. We compare and contrast these different but complimentary frameworks and highlight various recent progresses in each of them.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"143 ","pages":"Article 104175"},"PeriodicalIF":14.5,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143874822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2025-04-21DOI: 10.1016/j.ppnp.2025.104174
James Daniel Brandenburg , Spencer R. Klein , Zhangbu Xu , Shuai Yang , Wangmei Zha , Jian Zhou
Photoproduction in ultra-peripheral relativistic heavy-ion collisions displays many unique features, often involving quantum mechanical coherence and two-source interference between photon emission from the two ions. We review the recent experimental results from RHIC and the LHC and theoretical studies of coherent vector meson photoproduction, emphasizing the quantum mechanical aspects of the interactions and the entanglement between the final state particles. These studies enrich our understanding of non-local realism, underscore the critical role of the polarization of the photon source, quantum interference and nuclear effect on the gluon distribution. It paves a way for quantitatively probing the quantum nature of these high-energy nuclear collisions.
{"title":"Probing quantum phenomena through photoproduction in relativistic heavy-ion collisions","authors":"James Daniel Brandenburg , Spencer R. Klein , Zhangbu Xu , Shuai Yang , Wangmei Zha , Jian Zhou","doi":"10.1016/j.ppnp.2025.104174","DOIUrl":"10.1016/j.ppnp.2025.104174","url":null,"abstract":"<div><div>Photoproduction in ultra-peripheral relativistic heavy-ion collisions displays many unique features, often involving quantum mechanical coherence and two-source interference between photon emission from the two ions. We review the recent experimental results from RHIC and the LHC and theoretical studies of coherent vector meson photoproduction, emphasizing the quantum mechanical aspects of the interactions and the entanglement between the final state particles. These studies enrich our understanding of non-local realism, underscore the critical role of the polarization of the photon source, quantum interference and nuclear effect on the gluon distribution. It paves a way for quantitatively probing the quantum nature of these high-energy nuclear collisions.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"143 ","pages":"Article 104174"},"PeriodicalIF":14.5,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143877467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2025-04-16DOI: 10.1016/j.ppnp.2025.104173
Ani Aprahamian , Kevin Lee , Shelly R. Lesher , Roelof Bijker
<div><div>This is a review on the nature of low-lying 0<span><math><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup></math></span> states in the excitation spectra of deformed nuclei. Early in the history of the field, Bohr–Mottelson–Rainwater won the 1975 Nobel prize in physics for connecting nucleon motion to the emergent collective behavior observed in nuclei. They essentially described the nucleus as a geometric shape with rotational and vibrational degrees of freedom. The lowest shape affecting vibrations in nuclei would be quadrupole (<span><math><mi>λ</mi></math></span>=2). In spherical nuclei, the oscillations of the ground state shape were expected to yield an energy spectrum that could be described in terms of single and multiple quadrupole phonons. In deformed nuclei, rotational motion is prominent and could be described in terms of a rigid rotor. The question in nuclear structure physics that has remained unanswered for decades is the viability of a deformed nucleus to sustain oscillations or vibrations built on the ground state. The quadrupole oscillations in deformed nuclei could result in two types of vibrations: <span><math><mi>β</mi></math></span>-vibrations resulting from oscillations along the symmetry axis with K<span><math><mrow><msup><mrow></mrow><mrow><mi>π</mi></mrow></msup><mo>=</mo><msup><mrow><mn>0</mn></mrow><mrow><mo>+</mo></mrow></msup></mrow></math></span> and <span><math><mi>γ</mi></math></span>-vibrations breaking axial symmetry with a projection of K<span><math><mrow><msup><mrow></mrow><mrow><mi>π</mi></mrow></msup><mo>=</mo><msup><mrow><mn>2</mn></mrow><mrow><mo>+</mo></mrow></msup></mrow></math></span> on the symmetry axis. The K<span><math><mrow><msup><mrow></mrow><mrow><mi>π</mi></mrow></msup><mo>=</mo><msup><mrow><mn>2</mn></mrow><mrow><mo>+</mo></mrow></msup></mrow></math></span> or <span><math><mi>γ</mi></math></span>-vibrational bands are well characterized and accepted as oscillations around the g.s. The question which has remained open is the nature of the K<span><math><mrow><msup><mrow></mrow><mrow><mi>π</mi></mrow></msup><mo>=</mo><msup><mrow><mn>0</mn></mrow><mrow><mo>+</mo></mrow></msup></mrow></math></span> bands. Historically, 0<span><math><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup></math></span> states were difficult to observe and to measure, more recently however, there has been a large abundance of states identified. The discussions have shifted towards the characterization of these 0<span><math><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup></math></span> states. The systematics of the observed B(E2) values depopulating the K<span><math><mrow><msup><mrow></mrow><mrow><mi>π</mi></mrow></msup><mo>=</mo><msup><mrow><mn>0</mn></mrow><mrow><mo>+</mo></mrow></msup></mrow></math></span> bands were shown to be weaker than the K<span><math><mrow><msup><mrow></mrow><mrow><mi>π</mi></mrow></msup><mo>=</mo><msup><mrow><mn>2</mn></mrow><mrow><mo>+</mo></mrow></msup></mrow></math></span> band decay
{"title":"The nature of 0+ excitations in deformed nuclei","authors":"Ani Aprahamian , Kevin Lee , Shelly R. Lesher , Roelof Bijker","doi":"10.1016/j.ppnp.2025.104173","DOIUrl":"10.1016/j.ppnp.2025.104173","url":null,"abstract":"<div><div>This is a review on the nature of low-lying 0<span><math><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup></math></span> states in the excitation spectra of deformed nuclei. Early in the history of the field, Bohr–Mottelson–Rainwater won the 1975 Nobel prize in physics for connecting nucleon motion to the emergent collective behavior observed in nuclei. They essentially described the nucleus as a geometric shape with rotational and vibrational degrees of freedom. The lowest shape affecting vibrations in nuclei would be quadrupole (<span><math><mi>λ</mi></math></span>=2). In spherical nuclei, the oscillations of the ground state shape were expected to yield an energy spectrum that could be described in terms of single and multiple quadrupole phonons. In deformed nuclei, rotational motion is prominent and could be described in terms of a rigid rotor. The question in nuclear structure physics that has remained unanswered for decades is the viability of a deformed nucleus to sustain oscillations or vibrations built on the ground state. The quadrupole oscillations in deformed nuclei could result in two types of vibrations: <span><math><mi>β</mi></math></span>-vibrations resulting from oscillations along the symmetry axis with K<span><math><mrow><msup><mrow></mrow><mrow><mi>π</mi></mrow></msup><mo>=</mo><msup><mrow><mn>0</mn></mrow><mrow><mo>+</mo></mrow></msup></mrow></math></span> and <span><math><mi>γ</mi></math></span>-vibrations breaking axial symmetry with a projection of K<span><math><mrow><msup><mrow></mrow><mrow><mi>π</mi></mrow></msup><mo>=</mo><msup><mrow><mn>2</mn></mrow><mrow><mo>+</mo></mrow></msup></mrow></math></span> on the symmetry axis. The K<span><math><mrow><msup><mrow></mrow><mrow><mi>π</mi></mrow></msup><mo>=</mo><msup><mrow><mn>2</mn></mrow><mrow><mo>+</mo></mrow></msup></mrow></math></span> or <span><math><mi>γ</mi></math></span>-vibrational bands are well characterized and accepted as oscillations around the g.s. The question which has remained open is the nature of the K<span><math><mrow><msup><mrow></mrow><mrow><mi>π</mi></mrow></msup><mo>=</mo><msup><mrow><mn>0</mn></mrow><mrow><mo>+</mo></mrow></msup></mrow></math></span> bands. Historically, 0<span><math><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup></math></span> states were difficult to observe and to measure, more recently however, there has been a large abundance of states identified. The discussions have shifted towards the characterization of these 0<span><math><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup></math></span> states. The systematics of the observed B(E2) values depopulating the K<span><math><mrow><msup><mrow></mrow><mrow><mi>π</mi></mrow></msup><mo>=</mo><msup><mrow><mn>0</mn></mrow><mrow><mo>+</mo></mrow></msup></mrow></math></span> bands were shown to be weaker than the K<span><math><mrow><msup><mrow></mrow><mrow><mi>π</mi></mrow></msup><mo>=</mo><msup><mrow><mn>2</mn></mrow><mrow><mo>+</mo></mrow></msup></mrow></math></span> band decay","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"143 ","pages":"Article 104173"},"PeriodicalIF":14.5,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2025-02-24DOI: 10.1016/j.ppnp.2025.104164
A. Tumino , C.A. Bertulani , S. Cherubini , G.F. D’Agata , A. Di Pietro , P. Figuera , G.L. Guardo , M. Gulino , S. Hayakawa , M. La Cognata , M. La Commara , L. Lamia , D. Lattuada , M. Mazzocco , A.M. Moro , J. Mraźek , A.A. Oliva , S. Palmerini , R.G. Pizzone , G.G. Rapisarda , H. Yamaguchi
We review the status and perspectives of indirect methods that make use of transfer reactions. We focus on two of them that have been extensively used in the past decades to determine cross sections of reactions of astrophysical relevance: the Trojan Horse method and the Asymptotic Normalization Coefficients method. We provide a comprehensive description of the theory behind each of these techniques, followed by an overview of a selection of experiments carried out using these indirect tools.
{"title":"Indirect methods with transfer reactions: The Trojan Horse method and the Asymptotic Normalization Coefficient","authors":"A. Tumino , C.A. Bertulani , S. Cherubini , G.F. D’Agata , A. Di Pietro , P. Figuera , G.L. Guardo , M. Gulino , S. Hayakawa , M. La Cognata , M. La Commara , L. Lamia , D. Lattuada , M. Mazzocco , A.M. Moro , J. Mraźek , A.A. Oliva , S. Palmerini , R.G. Pizzone , G.G. Rapisarda , H. Yamaguchi","doi":"10.1016/j.ppnp.2025.104164","DOIUrl":"10.1016/j.ppnp.2025.104164","url":null,"abstract":"<div><div>We review the status and perspectives of indirect methods that make use of transfer reactions. We focus on two of them that have been extensively used in the past decades to determine cross sections of reactions of astrophysical relevance: the Trojan Horse method and the Asymptotic Normalization Coefficients method. We provide a comprehensive description of the theory behind each of these techniques, followed by an overview of a selection of experiments carried out using these indirect tools.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"143 ","pages":"Article 104164"},"PeriodicalIF":14.5,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143549466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Pub Date : 2025-02-11DOI: 10.1016/j.ppnp.2025.104163
P. Zakalek, T. Gutberlet, Th. Brückel
A review of neutron sources for large scale user facilities is provided, aimed at users of neutron sources who need to understand the characteristics and peculiarities of the different types of neutron sources in order to select the most suitable source for their needs and to optimize their experimental setups for their specific scientific requirements. To this end, we provide an overview of (i) the main nuclear processes used at user facilities to release neutrons from nuclei, namely fission, spallation, and low-energy nuclear reactions, (ii) the various possibilities to tailor the time structure and spectrum of free neutrons, from pulsing to moderation, (iii) the mechanisms to extract and transport neutron beams with desired properties in terms of flux, brilliance/brightness, spectrum, pulse shape, etc., (iii) the applications and related experimental requirements in major scientific fields, with emphasis on those with a larger user community, (iv) the technology and realization of research reactors and neutron spallation sources, and (v) the progress made in Compact Accelerator-driven Neutron Sources (CANS), but especially in High Current Accelerator-driven Neutron Sources (HiCANS).
HiCANS are the focus of the current review, as this entirely new type of facility could in the future play the role in the neutron ecosystem that national reactor-based sources have played in the past. As such, HiCANS do not aim for the highest neutron brightness, but rather for parameters such as resilience, reliability, flexibility, ease of access, minimization of radioactive waste, excellent signal-to-noise ratio and optimization of the price/performance ratio. These are key features needed to further expand the community of neutron users from science and industry to whom this review is addressed.
{"title":"Neutron sources for large scale user facilities: The potential of high current accelerator-driven neutron sources","authors":"P. Zakalek, T. Gutberlet, Th. Brückel","doi":"10.1016/j.ppnp.2025.104163","DOIUrl":"10.1016/j.ppnp.2025.104163","url":null,"abstract":"<div><div>A review of neutron sources for large scale user facilities is provided, aimed at users of neutron sources who need to understand the characteristics and peculiarities of the different types of neutron sources in order to select the most suitable source for their needs and to optimize their experimental setups for their specific scientific requirements. To this end, we provide an overview of (i) the main nuclear processes used at user facilities to release neutrons from nuclei, namely fission, spallation, and low-energy nuclear reactions, (ii) the various possibilities to tailor the time structure and spectrum of free neutrons, from pulsing to moderation, (iii) the mechanisms to extract and transport neutron beams with desired properties in terms of flux, brilliance/brightness, spectrum, pulse shape, etc., (iii) the applications and related experimental requirements in major scientific fields, with emphasis on those with a larger user community, (iv) the technology and realization of research reactors and neutron spallation sources, and (v) the progress made in Compact Accelerator-driven Neutron Sources (CANS), but especially in High Current Accelerator-driven Neutron Sources (HiCANS).</div><div>HiCANS are the focus of the current review, as this entirely new type of facility could in the future play the role in the neutron ecosystem that national reactor-based sources have played in the past. As such, HiCANS do not aim for the highest neutron brightness, but rather for parameters such as resilience, reliability, flexibility, ease of access, minimization of radioactive waste, excellent signal-to-noise ratio and optimization of the price/performance ratio. These are key features needed to further expand the community of neutron users from science and industry to whom this review is addressed.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"142 ","pages":"Article 104163"},"PeriodicalIF":14.5,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143428127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
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