Pub Date : 2026-01-30DOI: 10.1016/j.ppnp.2026.104233
Kristina D. Launey, Grigor H. Sargsyan, Alexis Mercenne, Jutta E. Escher, Darin C. Mumma
{"title":"Ab initio symmetry-adapted approaches to nuclear reactions","authors":"Kristina D. Launey, Grigor H. Sargsyan, Alexis Mercenne, Jutta E. Escher, Darin C. Mumma","doi":"10.1016/j.ppnp.2026.104233","DOIUrl":"https://doi.org/10.1016/j.ppnp.2026.104233","url":null,"abstract":"","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"198 1","pages":""},"PeriodicalIF":9.6,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146089311","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}
We review the role of the anomalous magnetic moment of the muon as a powerful probe of physics beyond the Standard Model (BSM), taking advantage of the final result of the Fermilab experiment and the recently updated Standard Model value. This review provides both a comprehensive summary of the current status, as well as an accessible entry point for phenomenologists with interests in dark matter, Higgs and electroweak or neutrino and flavour physics in the context of a wide range of BSM scenarios. It begins with a qualitative overview of the field and a collection of key properties and typical results. It then focuses on model-independent, generic formulas and classifies types of BSM scenarios with or without chiral enhancements. A strong emphasis of the review are the connections to a large number of other observables — ranging from the muon mass and the muon–Higgs coupling and related dipole observables to dark matter, neutrino masses and high-energy collider observables. Finally, we survey a number of well-motivated BSM scenarios such as dark photons, axion-like particles, the two-Higgs doublet model, supersymmetric models and models with leptoquarks, vector-like leptons or neutrino mass models. We discuss the impact of the updated Standard Model value for and of complementary constraints, exploring the phenomenology and identifying excluded and viable parameter regions.
{"title":"The muon magnetic moment and physics beyond the standard model","authors":"Peter Athron , Kilian Möhling , Dominik Stöckinger , Hyejung Stöckinger-Kim","doi":"10.1016/j.ppnp.2025.104225","DOIUrl":"10.1016/j.ppnp.2025.104225","url":null,"abstract":"<div><div>We review the role of the anomalous magnetic moment of the muon <span><math><msub><mrow><mi>a</mi></mrow><mrow><mi>μ</mi></mrow></msub></math></span> as a powerful probe of physics beyond the Standard Model (BSM), taking advantage of the final result of the Fermilab <span><math><mrow><mi>g</mi><mo>−</mo><mn>2</mn></mrow></math></span> experiment and the recently updated Standard Model value. This review provides both a comprehensive summary of the current status, as well as an accessible entry point for phenomenologists with interests in dark matter, Higgs and electroweak or neutrino and flavour physics in the context of a wide range of BSM scenarios. It begins with a qualitative overview of the field and a collection of key properties and typical results. It then focuses on model-independent, generic formulas and classifies types of BSM scenarios with or without chiral enhancements. A strong emphasis of the review are the connections to a large number of other observables — ranging from the muon mass and the muon–Higgs coupling and related dipole observables to dark matter, neutrino masses and high-energy collider observables. Finally, we survey a number of well-motivated BSM scenarios such as dark photons, axion-like particles, the two-Higgs doublet model, supersymmetric models and models with leptoquarks, vector-like leptons or neutrino mass models. We discuss the impact of the updated Standard Model value for <span><math><msub><mrow><mi>a</mi></mrow><mrow><mi>μ</mi></mrow></msub></math></span> and of complementary constraints, exploring the phenomenology and identifying excluded and viable parameter regions.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"148 ","pages":"Article 104225"},"PeriodicalIF":17.9,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145962509","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}
The strong interaction, described within the Standard Model of particle physics by quantum chromodynamics (QCD), plays a fundamental role in understanding the structure and the stability of matter. Despite significant advances, the low-energy QCD regime remains poorly understood due to its non-perturbative nature. Kaonic atoms, in which a negatively charged kaon is bound to a nucleus via electromagnetic interaction, offer a unique experimental tool to investigate the strong interactions in the strangeness sector. Their study provides key information on the antikaon–nucleon interaction at threshold energy, essential for refining the relative theoretical models. This work reviews the current status of kaonic atom research, highlighting recent experimental findings and their impact on our understanding of the strong interaction. We discuss the formation processes, the role of X-ray spectroscopy in probing strong-interaction effects, and the latest results from DANE and J-PARC experimental facilities. Future perspectives, including planned experiments aimed at further improving the precision of the measurements and the potentiality of also measuring the high-n transitions as precision probes for quantum electrodynamics (QED) with strangeness, are also reviewed.
{"title":"Light kaonic atoms as probes of fundamental interactions in strange systems","authors":"Catalina Curceanu , Francesco Sgaramella , Massimiliano Bazzi , Tadashi Hashimoto , Mihail Iliescu , Alessandro Scordo , Diana Sirghi , Florin Sirghi","doi":"10.1016/j.ppnp.2026.104226","DOIUrl":"10.1016/j.ppnp.2026.104226","url":null,"abstract":"<div><div>The strong interaction, described within the Standard Model of particle physics by quantum chromodynamics (QCD), plays a fundamental role in understanding the structure and the stability of matter. Despite significant advances, the low-energy QCD regime remains poorly understood due to its non-perturbative nature. Kaonic atoms, in which a negatively charged kaon is bound to a nucleus via electromagnetic interaction, offer a unique experimental tool to investigate the strong interactions in the strangeness sector. Their study provides key information on the antikaon–nucleon interaction at threshold energy, essential for refining the relative theoretical models. This work reviews the current status of kaonic atom research, highlighting recent experimental findings and their impact on our understanding of the strong interaction. We discuss the formation processes, the role of X-ray spectroscopy in probing strong-interaction effects, and the latest results from DA<span><math><mi>Φ</mi></math></span>NE and J-PARC experimental facilities. Future perspectives, including planned experiments aimed at further improving the precision of the measurements and the potentiality of also measuring the high-n transitions as precision probes for quantum electrodynamics (QED) with strangeness, are also reviewed.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"147 ","pages":"Article 104226"},"PeriodicalIF":17.9,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145957102","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 : 2025-12-29DOI: 10.1016/j.ppnp.2025.104224
T.C. Jude
<div><div>The discoveries of the pentaquark states and <span><math><mrow><mi>X</mi><mi>Y</mi><mi>Z</mi></mrow></math></span> mesons in the charm quark sector initiated a new epoch in hadron physics, where the existence of exotic multi-quark states beyond conventional valence three quark and quark–antiquark systems has been unambiguously confirmed. Such states could manifest as single colour bound objects, or evolve from meson–baryon and meson–meson interactions, creating molecular like systems and re-scattering effects near production thresholds. Molecular-like structures may be apparent over the full quark flavour and mass range, with equivalent states evidenced in the light, <span><math><mrow><mi>u</mi><mi>d</mi><mi>s</mi></mrow></math></span> quark sector. This is the focus of the BGOOD photoproduction experiment at the ELSA electron accelerator at the University of Bonn. The combination of a central electromagnetic calorimeter and forward charged particle spectrometer permits access to low momentum exchange kinematics and corresponding forward meson production angles, which is crucial to study spatially extended, molecular-like structure which may manifest in reaction mechanisms.</div><div>The reviewed publications span two areas of research connected via the kinematics associated with molecular-like hadron structure. The first is in the strangeness sector where meson–baryon dynamics may play prominent roles. Forward angle differential cross section measurements from threshold for <span><math><mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><mi>Λ</mi></mrow></math></span>, <span><math><mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>Σ</mi></mrow><mrow><mn>0</mn></mrow></msup></mrow></math></span>, <span><math><mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><mi>Σ</mi><msup><mrow><mrow><mo>(</mo><mn>1385</mn><mo>)</mo></mrow></mrow><mrow><mn>0</mn></mrow></msup></mrow></math></span>, <span><math><mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><mi>Λ</mi><mrow><mo>(</mo><mn>1405</mn><mo>)</mo></mrow></mrow></math></span> and <span><math><mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><mi>Λ</mi><mrow><mo>(</mo><mn>1520</mn><mo>)</mo></mrow></mrow></math></span> indicate an equivalence to the <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>C</mi></mrow></msub></math></span> states observed at the <span><math><mrow><mi>D</mi><msub><mrow><mi>Σ</mi></mrow><mrow><mi>C</mi></mrow></msub></mrow></math></span>, <span><math><mrow><mi>D</mi><msubsup><mrow><mi>Σ</mi></mrow><mrow><mi>C</mi></mrow><mrow><mo>∗</mo></mrow></msubsup></mrow></math></span> and <span><math><mrow><msup><mrow><mi>D</mi></mrow><mrow><mo>∗</mo></mrow></msup><msub><mrow><mi>Σ</mi></mrow><mrow><mi>C</mi></mrow></msub></mrow></math></span> thresholds. The second area of research is in the non-strange baryon–baryon sector, where coherent meson photoproduction off the deuteron enables access
{"title":"Studies of unconventional baryon structure in the light quark sector with the BGOOD photoproduction experiment","authors":"T.C. Jude","doi":"10.1016/j.ppnp.2025.104224","DOIUrl":"10.1016/j.ppnp.2025.104224","url":null,"abstract":"<div><div>The discoveries of the pentaquark states and <span><math><mrow><mi>X</mi><mi>Y</mi><mi>Z</mi></mrow></math></span> mesons in the charm quark sector initiated a new epoch in hadron physics, where the existence of exotic multi-quark states beyond conventional valence three quark and quark–antiquark systems has been unambiguously confirmed. Such states could manifest as single colour bound objects, or evolve from meson–baryon and meson–meson interactions, creating molecular like systems and re-scattering effects near production thresholds. Molecular-like structures may be apparent over the full quark flavour and mass range, with equivalent states evidenced in the light, <span><math><mrow><mi>u</mi><mi>d</mi><mi>s</mi></mrow></math></span> quark sector. This is the focus of the BGOOD photoproduction experiment at the ELSA electron accelerator at the University of Bonn. The combination of a central electromagnetic calorimeter and forward charged particle spectrometer permits access to low momentum exchange kinematics and corresponding forward meson production angles, which is crucial to study spatially extended, molecular-like structure which may manifest in reaction mechanisms.</div><div>The reviewed publications span two areas of research connected via the kinematics associated with molecular-like hadron structure. The first is in the strangeness sector where meson–baryon dynamics may play prominent roles. Forward angle differential cross section measurements from threshold for <span><math><mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><mi>Λ</mi></mrow></math></span>, <span><math><mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>Σ</mi></mrow><mrow><mn>0</mn></mrow></msup></mrow></math></span>, <span><math><mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><mi>Σ</mi><msup><mrow><mrow><mo>(</mo><mn>1385</mn><mo>)</mo></mrow></mrow><mrow><mn>0</mn></mrow></msup></mrow></math></span>, <span><math><mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><mi>Λ</mi><mrow><mo>(</mo><mn>1405</mn><mo>)</mo></mrow></mrow></math></span> and <span><math><mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><mi>Λ</mi><mrow><mo>(</mo><mn>1520</mn><mo>)</mo></mrow></mrow></math></span> indicate an equivalence to the <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>C</mi></mrow></msub></math></span> states observed at the <span><math><mrow><mi>D</mi><msub><mrow><mi>Σ</mi></mrow><mrow><mi>C</mi></mrow></msub></mrow></math></span>, <span><math><mrow><mi>D</mi><msubsup><mrow><mi>Σ</mi></mrow><mrow><mi>C</mi></mrow><mrow><mo>∗</mo></mrow></msubsup></mrow></math></span> and <span><math><mrow><msup><mrow><mi>D</mi></mrow><mrow><mo>∗</mo></mrow></msup><msub><mrow><mi>Σ</mi></mrow><mrow><mi>C</mi></mrow></msub></mrow></math></span> thresholds. The second area of research is in the non-strange baryon–baryon sector, where coherent meson photoproduction off the deuteron enables access","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"147 ","pages":"Article 104224"},"PeriodicalIF":17.9,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894294","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 : 2025-11-22DOI: 10.1016/j.ppnp.2025.104215
Dieter Ackermann
After more than half a century since the first predictions of the so-called “island of stability of superheavy nuclei”, exploring the limits of nuclear stability at highest atomic numbers is still one of the most prominent challenges in low-energy nuclear physics. These exotic nuclear species reveal their character and details of some of their properties through their induced or spontaneous disintegration.
The achievements in the field of superheavy nuclei (SHN) research, which involves studying the production and decay of the heaviest nuclear species, have been reported in a number of review papers. In the introduction of this paper, references are provided to review papers, summarizing the many aspects of SHN research in other disciplines, like chemistry, atomic physics, and earlier work on nuclear structure, including in-beam spectroscopy, and superheavy element (SHE) synthesis.
This review is an attempt to summarize the experimental progress that has been made in recent years by employing the versatile tool park of Decay Spectroscopy After Separation (DSAS) for the heaviest isotopes from 99 (einsteinium) to 118 (oganesson). DSAS, with its major instrumentation components heavy-ion accelerator, separator and decay detection, is the only way to access the heaviest nuclei up to oganesson. While in-beam -spectroscopy has reached 256Rf in terms of the highest atomic number and mass number , SHE chemistry succeeded to sort flerovium ( 114) as the heaviest element into the periodic table. Laser spectroscopy and precise mass measurements are limited basically to the nobelium/fermium region, with high-precision Penning-trap mass-measurements being performed for 256Lr and 257Rf, and with the 257Db mass obtained, using a multi-reflection time-of-flight mass spectrometer (MRToF MS).
Apart from a brief introduction of the method (DSAS) and some nuclear structure features of SHN, the experimental findings reported in literature are summarized in this review, including a table listing the major decay properties, providing a comprehensive collection of references to experimental publications for each known isotope and isomeric state.
{"title":"Decay spectroscopy of heavy and superheavy nuclei","authors":"Dieter Ackermann","doi":"10.1016/j.ppnp.2025.104215","DOIUrl":"10.1016/j.ppnp.2025.104215","url":null,"abstract":"<div><div>After more than half a century since the first predictions of the so-called <em>“island of stability of superheavy nuclei”</em>, exploring the limits of nuclear stability at highest atomic numbers is still one of the most prominent challenges in low-energy nuclear physics. These exotic nuclear species reveal their character and details of some of their properties through their induced or spontaneous disintegration.</div><div>The achievements in the field of superheavy nuclei (SHN) research, which involves studying the production and decay of the heaviest nuclear species, have been reported in a number of review papers. In the introduction of this paper, references are provided to review papers, summarizing the many aspects of SHN research in other disciplines, like chemistry, atomic physics, and earlier work on nuclear structure, including in-beam spectroscopy, and superheavy element (SHE) synthesis.</div><div>This review is an attempt to summarize the experimental progress that has been made in recent years by employing the versatile tool park of Decay Spectroscopy After Separation (DSAS) for the heaviest isotopes from <span><math><mrow><mi>Z</mi><mo>=</mo></mrow></math></span> 99 (einsteinium) to <span><math><mrow><mi>Z</mi><mo>=</mo></mrow></math></span> 118 (oganesson). DSAS, with its major instrumentation components heavy-ion accelerator, separator and decay detection, is the only way to access the heaviest nuclei up to oganesson. While in-beam <span><math><mi>γ</mi></math></span>-spectroscopy has reached <sup>256</sup>Rf in terms of the highest atomic number <span><math><mi>Z</mi></math></span> and mass number <span><math><mi>A</mi></math></span>, SHE chemistry succeeded to sort flerovium (<span><math><mrow><mi>Z</mi><mo>=</mo></mrow></math></span> <!--> <!-->114) as the heaviest element into the periodic table. Laser spectroscopy and precise mass measurements are limited basically to the nobelium/fermium region, with high-precision Penning-trap mass-measurements being performed for <sup>256</sup>Lr and <sup>257</sup>Rf, and with the <sup>257</sup>Db mass obtained, using a multi-reflection time-of-flight mass spectrometer (MRToF MS).</div><div>Apart from a brief introduction of the method (DSAS) and some nuclear structure features of SHN, the experimental findings reported in literature are summarized in this review, including a table listing the major decay properties, providing a comprehensive collection of references to experimental publications for each known isotope and isomeric state.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"147 ","pages":"Article 104215"},"PeriodicalIF":17.9,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145575477","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 : 2025-11-01DOI: 10.1016/j.ppnp.2025.104213
Michael Döring , Johann Haidenbauer , Maxim Mai , Toru Sato
Dynamical coupled-channel (DCC) approaches parametrize the interactions and dynamics of two and more hadrons and their response to different electroweak probes. The inclusion of unitarity, three-body channels, and other properties from scattering theory allows for a reliable extraction of resonance spectra and their properties from data. We review the formalism and application of the ANL–Osaka, the Juelich–Bonn–Washington, and other DCC approaches in the context of light baryon resonances from meson, (virtual) photon, and neutrino-induced reactions, as well as production reactions, strange baryons, light mesons, heavy meson systems, exotics, and baryon–baryon interactions. Finally, we also provide a connection of the formalism to study finite-volume spectra obtained in Lattice QCD, and review applications involving modern statistical and machine learning tools.
{"title":"Dynamical coupled-channel models for hadron dynamics","authors":"Michael Döring , Johann Haidenbauer , Maxim Mai , Toru Sato","doi":"10.1016/j.ppnp.2025.104213","DOIUrl":"10.1016/j.ppnp.2025.104213","url":null,"abstract":"<div><div>Dynamical coupled-channel (DCC) approaches parametrize the interactions and dynamics of two and more hadrons and their response to different electroweak probes. The inclusion of unitarity, three-body channels, and other properties from scattering theory allows for a reliable extraction of resonance spectra and their properties from data. We review the formalism and application of the ANL–Osaka, the Juelich–Bonn–Washington, and other DCC approaches in the context of light baryon resonances from meson, (virtual) photon, and neutrino-induced reactions, as well as production reactions, strange baryons, light mesons, heavy meson systems, exotics, and baryon–baryon interactions. Finally, we also provide a connection of the formalism to study finite-volume spectra obtained in Lattice QCD, and review applications involving modern statistical and machine learning tools.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"146 ","pages":"Article 104213"},"PeriodicalIF":17.9,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145423984","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}
We review recent progress in our understanding of the nucleon excitation spectrum. Thanks to dedicated efforts at facilities such as ELSA, MAMI and Jefferson Lab, several new nucleon resonances have been discovered, and evidence for previously elusive states has been significantly improved. Numerous decay channels have been observed for the first time, and resonance properties are being extracted from these data by several groups through coupled-channel analyses of varying complexity. Electroproduction experiments have provided further insights into the internal structure of light baryon resonances — for example, the long-debated Roper resonance is observed as a three-quark state with a significant meson-cloud component. While the non-relativistic quark model remains a valuable tool for organizing the spectrum of nucleon and resonances, a variety of theoretical frameworks have emerged to offer deeper understanding, including phenomenological quark models, holographic QCD, functional methods, effective field theories, and lattice QCD. We examine the interplay between these approaches, highlight their respective strengths and explore how they complement each other in shaping our knowledge of light baryon resonances. We address several open questions in baryon spectroscopy, including the nature of the enigmatic , ongoing searches for exotic states such as hybrid baryons and pentaquarks, and the dichotomy between microscopic descriptions of baryons in terms of quarks and gluons versus effective hadronic descriptions based on meson–baryon dynamics.
{"title":"The impact of γN and γ∗N interactions on our understanding of nucleon excitations","authors":"Volker Burkert , Gernot Eichmann , Eberhard Klempt","doi":"10.1016/j.ppnp.2025.104214","DOIUrl":"10.1016/j.ppnp.2025.104214","url":null,"abstract":"<div><div>We review recent progress in our understanding of the nucleon excitation spectrum. Thanks to dedicated efforts at facilities such as ELSA, MAMI and Jefferson Lab, several new nucleon resonances have been discovered, and evidence for previously elusive states has been significantly improved. Numerous decay channels have been observed for the first time, and resonance properties are being extracted from these data by several groups through coupled-channel analyses of varying complexity. Electroproduction experiments have provided further insights into the internal structure of light baryon resonances — for example, the long-debated Roper resonance <span><math><mrow><mi>N</mi><mrow><mo>(</mo><mn>1440</mn><mo>)</mo></mrow></mrow></math></span> is observed as a three-quark state with a significant meson-cloud component. While the non-relativistic quark model remains a valuable tool for organizing the spectrum of nucleon and <span><math><mi>Δ</mi></math></span> resonances, a variety of theoretical frameworks have emerged to offer deeper understanding, including phenomenological quark models, holographic QCD, functional methods, effective field theories, and lattice QCD. We examine the interplay between these approaches, highlight their respective strengths and explore how they complement each other in shaping our knowledge of light baryon resonances. We address several open questions in baryon spectroscopy, including the nature of the enigmatic <span><math><mrow><mi>Λ</mi><mrow><mo>(</mo><mn>1405</mn><mo>)</mo></mrow></mrow></math></span>, ongoing searches for exotic states such as hybrid baryons and pentaquarks, and the dichotomy between microscopic descriptions of baryons in terms of quarks and gluons versus effective hadronic descriptions based on meson–baryon dynamics.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"146 ","pages":"Article 104214"},"PeriodicalIF":17.9,"publicationDate":"2025-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145485584","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 : 2025-09-12DOI: 10.1016/j.ppnp.2025.104199
Prabal Adhikari , Martin Ammon , Sidney S. Avancini , Alejandro Ayala , Aritra Bandyopadhyay , David Blaschke , Fabio L. Braghin , Pavel Buividovich , Rafael P. Cardoso , Casey Cartwright , Jorge David Castaño-Yepes , Maxim N. Chernodub , Máximo Coppola , Mayusree Das , Mariana Dutra , Gergely Endrődi , Jianjun Fang , Ricardo L.S. Farias , Eduardo S. Fraga , Arthur Frazon , Zenia Zuraiq
Magnetic fields are ubiquitous across different physical systems of current interest; from the early Universe, compact astrophysical objects, and heavy-ion collisions to condensed matter systems. A proper treatment of the effects produced by magnetic fields during the dynamical evolution of these systems can help to understand observables that otherwise show puzzling behavior. Furthermore, when these fields are comparable to or stronger than , they serve as excellent probes to help elucidate the physics of strongly interacting matter under extreme conditions of temperature and density. This work provides a detailed report that contains in-depth analysis and expert insights into the specific topic of the effects of strong magnetic fields on QED and QCD systems. In this sense, the report is intended as a white paper contribution to the field. The subjects developed include the modification of meson static properties such as masses and form factors, the chiral magnetic effect, the description of anomalous transport coefficients, superconductivity in extreme magnetic fields, the properties of neutron stars, the evolution of heavy-ion collisions, as well as effects on the QCD phase diagram. We describe recent theory and phenomenological developments using effective models as well as LQCD methods. The work was motivated by presentations and discussions during the “Workshop on Strongly Interacting Matter in Strong Electromagnetic Fields” that took place in the European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*) in the city of Trento, Italy, September 25–29, 2023.
{"title":"Strongly interacting matter in extreme magnetic fields","authors":"Prabal Adhikari , Martin Ammon , Sidney S. Avancini , Alejandro Ayala , Aritra Bandyopadhyay , David Blaschke , Fabio L. Braghin , Pavel Buividovich , Rafael P. Cardoso , Casey Cartwright , Jorge David Castaño-Yepes , Maxim N. Chernodub , Máximo Coppola , Mayusree Das , Mariana Dutra , Gergely Endrődi , Jianjun Fang , Ricardo L.S. Farias , Eduardo S. Fraga , Arthur Frazon , Zenia Zuraiq","doi":"10.1016/j.ppnp.2025.104199","DOIUrl":"10.1016/j.ppnp.2025.104199","url":null,"abstract":"<div><div>Magnetic fields are ubiquitous across different physical systems of current interest; from the early Universe, compact astrophysical objects, and heavy-ion collisions to condensed matter systems. A proper treatment of the effects produced by magnetic fields during the dynamical evolution of these systems can help to understand observables that otherwise show puzzling behavior. Furthermore, when these fields are comparable to or stronger than <span><math><msub><mrow><mi>Λ</mi></mrow><mrow><mtext>QCD</mtext></mrow></msub></math></span>, they serve as excellent probes to help elucidate the physics of strongly interacting matter under extreme conditions of temperature and density. This work provides a detailed report that contains in-depth analysis and expert insights into the specific topic of the effects of strong magnetic fields on QED and QCD systems. In this sense, the report is intended as a white paper contribution to the field. The subjects developed include the modification of meson static properties such as masses and form factors, the chiral magnetic effect, the description of anomalous transport coefficients, superconductivity in extreme magnetic fields, the properties of neutron stars, the evolution of heavy-ion collisions, as well as effects on the QCD phase diagram. We describe recent theory and phenomenological developments using effective models as well as LQCD methods. The work was motivated by presentations and discussions during the “Workshop on Strongly Interacting Matter in Strong Electromagnetic Fields” that took place in the European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*) in the city of Trento, Italy, September 25–29, 2023.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"146 ","pages":"Article 104199"},"PeriodicalIF":17.9,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145182896","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 : 2025-09-04DOI: 10.1016/j.ppnp.2025.104200
L.F. Pašteka , E. Eliav , M.L. Reitsma , A. Borschevsky
Theory can provide important support at all the stages of spectroscopic experiments, from planning the measurements to the interpretation of the results. Such support is particularly valuable for the challenging experiments on heavy, unstable, and superheavy elements and for precision measurements aimed at testing the Standard Model of particle physics. To be reliable and useful in experimental context, theoretical predictions should be based on high-accuracy calculations. For heavy elements, such calculations must treat both relativistic effects and electron correlation on the highest possible level. Relativistic coupled cluster is considered one of the most powerful methods for accurate calculations on heavy many-electron atoms and molecules. This approach is highly accurate and versatile and can be used to obtain energies and a variety of atomic and molecular properties. Furthermore, its robust and transparent formulation allows for systematic improvement of the accuracy of the calculated results and for assigning uncertainties on theoretical values. The Fock-space coupled cluster (FSCC) variant of this method is particularly useful in the context of spectroscopic measurements as it provides access to atomic spectra and properties of the excited states. In this review, we present in detail the relativistic coupled cluster approach and its FSCC variant. We provide a description of the computational procedure used for accurate calculations and for assigning uncertainties. Outstanding recent examples of application to atomic properties, focusing on the experimental context, are presented. Finally, we provide a brief discussion of the perspectives for future developments and applications of the CC approach.
{"title":"Relativistic atomic structure calculations in support of spectroscopy","authors":"L.F. Pašteka , E. Eliav , M.L. Reitsma , A. Borschevsky","doi":"10.1016/j.ppnp.2025.104200","DOIUrl":"10.1016/j.ppnp.2025.104200","url":null,"abstract":"<div><div>Theory can provide important support at all the stages of spectroscopic experiments, from planning the measurements to the interpretation of the results. Such support is particularly valuable for the challenging experiments on heavy, unstable, and superheavy elements and for precision measurements aimed at testing the Standard Model of particle physics. To be reliable and useful in experimental context, theoretical predictions should be based on high-accuracy calculations. For heavy elements, such calculations must treat both relativistic effects and electron correlation on the highest possible level. Relativistic coupled cluster is considered one of the most powerful methods for accurate calculations on heavy many-electron atoms and molecules. This approach is highly accurate and versatile and can be used to obtain energies and a variety of atomic and molecular properties. Furthermore, its robust and transparent formulation allows for systematic improvement of the accuracy of the calculated results and for assigning uncertainties on theoretical values. The Fock-space coupled cluster (FSCC) variant of this method is particularly useful in the context of spectroscopic measurements as it provides access to atomic spectra and properties of the excited states. In this review, we present in detail the relativistic coupled cluster approach and its FSCC variant. We provide a description of the computational procedure used for accurate calculations and for assigning uncertainties. Outstanding recent examples of application to atomic properties, focusing on the experimental context, are presented. Finally, we provide a brief discussion of the perspectives for future developments and applications of the CC approach.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"146 ","pages":"Article 104200"},"PeriodicalIF":17.9,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145098727","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 : 2025-07-21DOI: 10.1016/j.ppnp.2025.104198
Ralf Schützhold
The goal of this article is to review developments regarding the use of ultra-cold atoms as quantum simulators. Special emphasis is placed on relativistic quantum phenomena, which are presumably most interesting for the audience of this journal. After a brief introduction into the main idea of quantum simulators and the basic physics of ultra-cold atoms, relativistic quantum phenomena of linear fields are discussed, including Hawking radiation, the Unruh effect, cosmological particle creation, the Gibbons–Hawking and Ginzburg effects, super-radiance, Sauter–Schwinger and Breit–Wheeler pair creation, as well as the dynamical Casimir effect. After that, the focus is shifted to phenomena of non-linear fields, such as the sine–Gordon model, the Kibble–Zurek mechanism, false-vacuum decay, and quantum back-reaction. In order to place everything into proper context, the basic underlying mechanisms of these phenomena are briefly recapitulated before their simulators are discussed. Even though effort is made to provide a review as fair as possible, there can be no claim of completeness and the selection as well as the relative weights of the topics may well reflect the personal view and taste of the author.
{"title":"Ultra-cold atoms as quantum simulators for relativistic phenomena","authors":"Ralf Schützhold","doi":"10.1016/j.ppnp.2025.104198","DOIUrl":"10.1016/j.ppnp.2025.104198","url":null,"abstract":"<div><div>The goal of this article is to review developments regarding the use of ultra-cold atoms as quantum simulators. Special emphasis is placed on relativistic quantum phenomena, which are presumably most interesting for the audience of this journal. After a brief introduction into the main idea of quantum simulators and the basic physics of ultra-cold atoms, relativistic quantum phenomena of linear fields are discussed, including Hawking radiation, the Unruh effect, cosmological particle creation, the Gibbons–Hawking and Ginzburg effects, super-radiance, Sauter–Schwinger and Breit–Wheeler pair creation, as well as the dynamical Casimir effect. After that, the focus is shifted to phenomena of non-linear fields, such as the sine–Gordon model, the Kibble–Zurek mechanism, false-vacuum decay, and quantum back-reaction. In order to place everything into proper context, the basic underlying mechanisms of these phenomena are briefly recapitulated before their simulators are discussed. Even though effort is made to provide a review as fair as possible, there can be no claim of completeness and the selection as well as the relative weights of the topics may well reflect the personal view and taste of the author.</div></div>","PeriodicalId":412,"journal":{"name":"Progress in Particle and Nuclear Physics","volume":"145 ","pages":"Article 104198"},"PeriodicalIF":17.9,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144722325","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}
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