High Energy Physics Seminar

Speaker: Stanley J. Brodsky, SLAC & Stanford University

Title: Supersymmetric Features of Hadron Physics, Intrinsic Heavy Quarks, and other Novel Properties of Quantum Chromodynamics

Refreshments available at 1:30 pm.

Date: Tue, 16 Jan 2018, 1:45 pm – 2:45 pm

Type: Seminar

Location: 1400 BPS Bldg.

I will discuss a new approach to hadron dynamics and spectroscopy based on "light-front holography", a formalism which relates the bound-state amplitudes in the fifth dimension of AdS space to the boost-invariant light-front wavefunctions describing the structure of hadrons in physical space-time. The result is a set of frame-independent bound-state wave equations which incorporate quark confinement and predict many observed spectroscopic and dynamical features of hadron physics, such as linear Regge trajectories with universal slope in both the radial quantum number and the internal orbital angular momentum. Generalizing this procedure using superconformal algebra leads to a unified Regge spectroscopy of meson, baryon, and tetraquarks, including remarkable supersymmetric relations between the masses of mesons and baryons. The formalism also predicts nonperturbative hadronic observables such as structure functions, transverse momentum distributions, as well as distribution amplitudes. The analytic behavior of the QCD coupling controlling quark and gluon interactions, both at large and small momentum transfer, is determined. The implementation of conformal constraints leads to the elimination of renormalization scale ambiguities for perturbative QCD calculations.

This new approach to hadron dynamics also predicts an "intrinsic" component of the heavy quark distribution of the proton's PDF at high momentum fraction x which arises from amplitudes where the heavy quarks are multiply connected to the proton's valence quarks. The intrinsic heavy quark contributions lead to novel phenomena such as the hadroproduction of the Higgs, single and double quarkonium production, and even doubly-heavy baryon production at high Feynman x. I will also discuss the implications of the intrinsic charm of hadrons for the extraterrestrial neutrino spectrum measured at IceCube.