BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:Pentaquark Spectroscopy in a Bethe Salpeter Approach DTSTART:20230925T140000Z DTEND:20230925T160000Z DTSTAMP:20260809T133058Z UID:c898c430-527b-40d6-a5d7-05a924632850 SEQUENCE:2 CREATED:20230922T081144Z DESCRIPTION:Abstract:One of the spectacular successes of this millennium&# x27\;s hadron spectroscopy experiments is the discovery of many exotic mes on states in the heavy-quark energy region\, which do not seem to fit into the conventional quark model picture. Our traditional understanding of ha drons is that they can be grouped into mesons (quark-antiquark states) and baryons (which are made of three valence quarks). Moreover\, over the las t years the LHCb collaboration has found prominent peaks in the J/ψ-proto n invariant mass spectrum. This implies a minimal quark content uudc-cbar and thus constitutes the first clear experimental evidence for pentaquarks . The proximity of those peaks to meson-baryon thresholds suggests a molec ular explanation in terms of meson-baryon molecules\, in analogy to severa l exotic meson candidates in the charmonium sector.The goal of this PhD pr oject is to establish a theoretical description of pentaquarks from a cova riant five-body Bethe-Salpeter equation in QCD\, namely as five-body syste ms made of four quarks and one antiquark where the (anti-)quarks interact through gluons. This is based on a body of preceding work on mesons\, bary ons and tetraquarks from 2-\, 3- and 4-body equations\, which have been su ccessful in describing the spectra and internal dynamics of these states. Therefore\, the generalization of the approach to the five-body problem wi ll substantially advance the status quo and deliver predictions on the spe ctrum and structure of pentaquarks directly from QCD.In this seminar\, I w ill mainly focus on three works: I will present the technical basis for tr eating the five-body equation for a scalar system\, which provides the sta rting point for detailed studies in view of the resonance behavior of pent aquarks\, their internal structure\, and also light-quark spectroscopy to investigate meson-cloud effects on baryons. I will also present the ongoin g work on the five-body equation using the leading tensor components. Seco ndly\, I will present the two-body equation for a pentaquark as a meson-ba ryon system and describe how the Dyson-Schwinger and Bethe-Salpeter equati ons work. Finally\, I will briefly discuss another project I have been wor king on\, namely the QCD contributions to flavor changing neutral currents which may pose constraints on flavor anomalies. LAST-MODIFIED:20230922T081206Z LOCATION:Online (Meeting-ID: 624 9382 9561 Password: 340344) URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/pentaquark-spectroscopy-in -a-bethe-salpeter-approach/ X-ALT-DESC;FMTTYPE=text/html:

Abstract:One of the spectacular successes of this millennium'\;s hadron spectroscopy expe riments is the discovery of many exotic meson states in the heavy-quark en ergy region\, which do not seem to fit into the conventional quark model p icture. Our traditional understanding of hadrons is that they can be group ed into mesons (quark-antiquark states) and baryons (which are made of thr ee valence quarks). Moreover\, over the last years the LHCb collaboration has found prominent peaks in the J/ψ-proton invariant mass spectrum. This implies a minimal quark content uudc-cbar and thus constitutes the first clear experimental evidence for pentaquarks. The proximity of those peaks to meson-baryon thresholds suggests a molecular explanation in terms of me son-baryon molecules\, in analogy to several exotic meson candidates in th e charmonium sector.

The goal of th is PhD project is to establish a theoretical description of pentaquarks fr om a covariant five-body Bethe-Salpeter equation in QCD\, namely as five-b ody systems made of four quarks and one antiquark where the (anti-)quarks interact through gluons. This is based on a body of preceding work on meso ns\, baryons and tetraquarks from 2-\, 3- and 4-body equations\, which hav e been successful in describing the spectra and internal dynamics of these states. Therefore\, the generalization of the approach to the five-body p roblem will substantially advance the status quo and deliver predictions o n the spectrum and structure of pentaquarks directly from QCD.

In this seminar\, I will mainly focus on three works: I will present the technical basis for treating the five-body equa tion for a scalar system\, which provides the starting point for detailed studies in view of the resonance behavior of pentaquarks\, their internal structure\, and also light-quark spectroscopy to investigate meson-cloud e ffects on baryons. I will also present the ongoing work on the five-body e quation using the leading tensor components. Secondly\, I will present the two-body equation for a pentaquark as a meson-baryon system and describe how the Dyson-Schwinger and Bethe-Salpeter equations work. Finally\, I wil l briefly discuss another project I have been working on\, namely the QCD contributions to flavor changing neutral currents which may pose constrain ts on flavor anomalies.

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