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X-ORIGINAL-URL:https://w3.lnf.infn.it
X-WR-CALDESC:Eventi per INFN-LNF
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TZID:Europe/Rome
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DTSTART:20250330T010000
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DTSTART:20251026T010000
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DTSTART;TZID=Europe/Rome:20251126T130000
DTEND;TZID=Europe/Rome:20251128T190000
DTSTAMP:20260510T232124
CREATED:20250905T104717Z
LAST-MODIFIED:20250905T104717Z
UID:39546-1764162000-1764356400@w3.lnf.infn.it
SUMMARY:Light Dark Sectors @ LNF (LDS@LNF)
DESCRIPTION:The Workshop on Light Dark Sectors @ LNF (LDS@LNF) will gather researchers to discuss recent progress in the study of light dark sectors (covering light dark matter\, axion-like particles\, dark photons\, and related scenarios). The program will cover topics ranging from theoretical motivations to novel experimental strategies\, with the aim of encouraging exchanges and fostering collaborations within the community. \nThis workshop is also supported by the PRIN2022K4B58X project “AxionOrigins: Towards a Complete Theory for the Origin of the Axion” (PI: L. Di Luzio)\, a collaborative effort involving INFN\, the University of Padua\, and Sapienza University of Rome. The meeting serves as the closing event of this initiative. \nThe workshop will take place in the Salvini Auditorium (Building 36\, access via the LNF secondary entrance at Via E. Fermi\, 60 – see map). \n(Talks by invitation only)
URL:/event/light-dark-sectors-lnf-ldslnf/
LOCATION:Aula Salvini
CATEGORIES:Conferenze & Workshops
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DTSTART;TZID=Europe/Rome:20251126T143000
DTEND;TZID=Europe/Rome:20251126T163000
DTSTAMP:20260510T232124
CREATED:20251119T102008Z
LAST-MODIFIED:20251119T102008Z
UID:39995-1764167400-1764174600@w3.lnf.infn.it
SUMMARY:Physics of θ-Vacua and Inevitability of Axions in Standard Model and Gravity.
DESCRIPTION:Speaker: Gia Dvali (LMU and MPP. Munich) \nIn this talk we first review why the CP-violating θ-vacuum is a built-in feature of QCD and how the mass of the η′-meson provides a direct experimental evidence for it. We then explain how the axion protects CP dynamically and define the axion-quality measure. This discussion\, in particular\, will make it transparent that the η′-meson is nothing but a poor-quality axion. Next\, we introduce the so-called gauge formulation of axion in which the axion emerges as intrinsic part of QCD gauge redundancy without the need of any anomalous global symmetry. By the power of gauge symmetry\, the gauge axion has an exact quality\, as it is protected agains arbitrary continuous deformations of the theory. Next\, we show that in a generic gauge theory the elimination of the θ vacua by an anomalous symmetry is correlated with the existence of a pseudo-scalar particle that non-linearly realizes that symmetry. Applied to the electroweak sector\, this implies the existence of a new particle\, a so-called ηw-meson\, which is sourced by the B+L-anomaly and gets its mass from the topological susceptibility of the electroweak vacuum. We then discuss how gravity opens up a whole new perspective on the axion\, promoting it into a consistency issue. Namely\, once coupled to gravity\, every topologically non-trivial gauge sector must be accompanied by the axion of exact quality. This requirement must be fulfilled by gravity itself which\, due to Eguchi-Hanson instantons\, possesses the CP-violating θ-vacuum. Strikingly\, this implies the existence of a “gravi-axion”\, a pseudo-Goldstone coupled via the gravitational chiral anomaly of spin-3/2 fermions. Thus\, the gravitational θ-vacuum demands the existence of local supersymmetry. In conclusion\, Standard Model is predicted to be accompanied by three axions\, one per each gauge sector: QCD\, electroweak and gravity. We discus some phenomenological and cosmological implications of the presented topics.
URL:/event/physics-of-%ce%b8-vacua-and-inevitability-of-axions-in-standard-model-and-gravity/
LOCATION:Aula Salvini
CATEGORIES:Seminari generali
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