Probing a Probing a Pion Pion with Photons with Photons Adnan - PowerPoint PPT Presentation

Probing a Probing a Pion Pion with Photons with Photons Adnan Adnan Bashir Bashir Collaborators: Collaborators: Collaborators: Collaborators: L. Albino, University of Michoacán, Mexico L. Albino, University of Michoacán, Mexico F. Akram F. Akram, University of Punjab, Pakistan , University of Punjab, Pakistan A. Ahmad, University of Michoacán, Mexico A. Ahmad, University of Michoacán, Mexico J. J. Aslam Aslam, , Quaid Quaid-i-Azam Azam University, Pakistan University, Pakistan A. Ayala, UNAM, Mexico . Ayala, UNAM, Mexico M.A. M.A. Bedolla Bedolla, University of Michoacán, Mexico , University of Michoacán, Mexico B. El B. El-Bennish Bennish, , Cruzeiro do sul Cruzeiro do sul, Brazil , Brazil R. Bermudez, University of Sonora, Mexico R. Bermudez, University of Sonora, Mexico J. Cobos J. Cobos, University of Michoacán, Mexico , University of Michoacán, Mexico Y.X. Liu, Peking University, China Y.X. Liu, Peking University, China L. Chang, University of Adelaide, Australia L. Chang, University of Adelaide, Australia M.R. Pennington, M.R. Pennington, JLab JLab, USA , USA L.X. Gutiérrez L.X. Gutiérrez, University of Michoacán, Mexico , University of Michoacán, Mexico J.R. Quintero, Huelva University, Spain J.R. Quintero, Huelva University, Spain A. A. Raya, Michoacán University, Mexico Raya, Michoacán University, Mexico E. Gutiérrez E. Gutiérrez, University of Michoacán, Mexico , University of Michoacán, Mexico M.E. Tejeda M.E. Tejeda, USON, Mexico , USON, Mexico K. Raya, University of Michoacán, Mexico K. Raya, University of Michoacán, Mexico D. Wilson, D. Wilson, Jlab Jlab, USA , USA C.D. Roberts, Argonne National Laboratory, USA C.D. Roberts, Argonne National Laboratory, USA P.C. Tandy, Kent State University, P.C. Tandy, Kent State University, USA USA XV Mexican Workshop on Particles and Fields XV Mexican Workshop on Particles and Fields Mazatlan, Mazatlan, México México 2-6 November 2015 6 November 2015

Contents Contents • • Facts and Challenges Facts and Challenges Facts and Challenges Facts and Challenges • • Pions Pions Pions and Pions and and Chiral and Chiral Chiral Symmetry Chiral Symmetry Symmetry Symmetry • • Schwinger Schwinger Schwinger-Dyson Equations Schwinger-Dyson Equations Dyson Equations Dyson Equations • • The Quark Propagator The Quark Propagator The Quark Propagator The Quark Propagator • • The Gluon Propagator The Gluon Propagator The Gluon Propagator The Gluon Propagator • • Bethe Bethe Bethe Salpeter Bethe Salpeter Salpeter Amplitude Salpeter Amplitude Amplitude Amplitude • • Pion Pion Pion Electromagnetic Form Factor Pion Electromagnetic Form Factor Electromagnetic Form Factor Electromagnetic Form Factor • • Pion Pion Pion Transition Form Factor Pion Transition Form Factor Transition Form Factor Transition Form Factor • • Other Mesons and Baryons Other Mesons and Baryons Other Mesons and Baryons Other Mesons and Baryons • • Further Challenges Further Challenges Further Challenges Further Challenges

Facts and Challenges Facts and Challenges • • Color degrees of freedom (quarks and gluons) are not Color degrees of freedom (quarks and gluons) are not Color degrees of freedom (quarks and gluons) are not Color degrees of freedom (quarks and gluons) are not observable observable observable (confinement). observable (confinement). (confinement). (confinement). • Dynamical • Dynamical Dynamical mass Dynamical mass mass generation mass generation generation generation for for for for massless massless massless quarks massless quarks quarks; quarks; (dynamical (dynamical (dynamical chiral (dynamical chiral chiral symmetry chiral symmetry symmetry breaking) symmetry breaking) breaking). breaking). • • Both these • Both these Both these phenomena Both these phenomena phenomena are phenomena are are emergent are emergent emergent and owe themselves emergent and owe themselves and owe themselves and owe themselves to large coupling strength in the infrared. to large coupling strength in the infrared. to large coupling strength in the infrared. to large coupling strength in the infrared. • How do we study • How do we study How do we study physics beyond perturbation theory How do we study physics beyond perturbation theory physics beyond perturbation theory? physics beyond perturbation theory? ? ? • Studying QCD: lattice, • Studying QCD: lattice, Studying QCD: lattice, Schwinger Studying QCD: lattice, Schwinger Schwinger-Dyson and Bethe Schwinger-Dyson and Bethe Dyson and Bethe- Dyson and Bethe- Salpeter Salpeter Salpeter equations Salpeter equations equations, equations, , chiral , chiral chiral perturbation theory, chiral perturbation theory, perturbation theory, perturbation theory, effective quark models. effective quark models. effective quark models. effective quark models.

Pions Pions and and Chiral Chiral Symmetry Breaking Symmetry Breaking In In October In October In October 1934 October 1934 1934, Hideki 1934, Hideki Hideki Yukawa Hideki Yukawa Yukawa Yukawa predicted predicted predicted the predicted the the existence the existence existence of existence of of of a “heavy a a “heavy a “heavy quantum” “heavy quantum” quantum” , meson, quantum” , meson, meson, exchanging meson, exchanging exchanging nuclear exchanging nuclear nuclear force nuclear force force between force between between between neutrons n neutrons n eutrons and eutrons and and protons and protons protons. protons. . . 1949 1949 1950 1950 1969 1969 2008 2008 It It It It was was was discovered was discovered discovered by discovered by by by Cecil Cecil Cecil Cecil Powel Powel Powel Powel in in in in 1949 1949 1949 in 1949 in in cosmic in cosmic cosmic ray cosmic ray ray ray tracks tracks racks in racks in in a photographic in a photographic photographic emulsion photographic emulsion emulsion. emulsion. . . Pion was Pion Pion Pion was was nicely was nicely nicely accommodated nicely accommodated accommodated accommodated in in in in The The The Eight The Eight Eight Fold Eight Fold Fold way Fold way way of way of of of Murray Murray Murray Gell Murray Gell Gell – Mann Gell – Mann Mann in Mann in in in 1961 1961 1961. 1961. . . Yoichiro Yoichiro Nambu Yoichiro Nambu Yoichiro Nambu associated Nambu associated associated it associated it it with it with with CSB with CSB CSB in CSB in in 1960 in 1960 1960. 1960.

Pions Pions and and Chiral Chiral Symmetry Breaking Symmetry Breaking Pions Pions are Pions Pions are are the are the the lightest the lightest lightest of lightest of of hadrons of hadrons hadrons. They hadrons. They They do They do do not do not not have not have have zero have zero zero zero mass. mass mass mass. . . A A typical typical typical meson typical meson meson like meson like like a like a ρ has ρ has has has a mass a mass mass of mass of of 770 of 770 770 MeV 770 MeV MeV while MeV while while the while the the the nucleon has nucleon nucleon has nucleon has a mass has a mass mass of mass of of of 940 940 940 MeV 940 MeV MeV. This MeV. This This is This is is consistent is consistent consistent with consistent with with a with a constituent constituent constituent u,d constituent u,d u,d, mass u,d, mass mass of mass of of of around around around around 300 300 300 MeV 300 MeV MeV. MeV. However, pions However, However, However, pions pions only pions only only weigh only weigh weigh weigh about about about about 140 140 140 140 MeV MeV MeV, MeV, , which , which which is which is is 1/5th is 1/5th th of th of of of the mass the the the mass mass of mass of of the of the the ρ . the ρ . This This This This cannot cannot cannot be cannot be be an be an an accident an accident accident. accident. The The connection The connection The connection of connection of of pions of pions pions with pions with with chiral with chiral chiral chiral symmetry symmetry symmetry symmetry breaking breaking breaking was breaking was was was present present in present in present in the in the the Gell the Gell Gell-Mann Gell-Mann Mann-Oakes Mann-Oakes Oakes-Renner Oakes-Renner Renner relation Renner relation relation. relation.

Pions Pions and and Chiral Chiral Symmetry Breaking Symmetry Breaking Dynamical chiral Dynamical Dynamical Dynamical chiral chiral symmery chiral symmery symmery breaking symmery breaking breaking yields breaking yields yields large yields large large effective large effective effective effective quark quark masses quark quark masses masses and masses and and the and the the existence the existence existence of existence of of of Goldstone Goldstone Goldstone bosons Goldstone bosons bosons: pions bosons: pions pions. pions. Nobel Prize 2008: Nobel Prize 2008: Nobel Prize 2008: Nobel Prize 2008: “for “for the “for the “for the discovery the discovery discovery of discovery of of of the the the the mechanism mechanism mechanism mechanism of of of of spontaneous spontaneous spontaneous spontaneous broken broken broken symmetry broken symmetry symmetry in symmetry in in subatomic in subatomic subatomic subatomic physics” physics” physics” physics” quark-anti-quark quark-anti-quark