Found 3 result(s)
Exceptional Seminar Jacob Sonnenschein (Tel Aviv University)
at: 14:00 room H503  abstract: I will start with briefly describing the HISH ( Holography In spired Hadronic String) model and reviewing the fits of the spectra of mesons, baryons, glueballs and exotic hadrons. I will present the determination of the hadron strong decay widths. The main decay mechanism is that of a string splitting into two strings. The corresponding total decay width behaves as Γ = πATL/2 where T and L are the tension and length of the string and A is a dimensionless universal constant. The partial width of a given decay mode is given by Γ_i/Γ = Φ_i exp(−2πCm^2_sep/T) where Φi is a phase space factor, msep is the mass of the ”quark” and ”antiquark” created at the splitting point, and C is a dimensionless coefficient close to unity. I will show the fits of the theoretical results to experimental data for mesons and baryons. I will examine both the linearity in L and the expo nential suppression factor. The linearity was found to agree with the data well for mesons but less for baryons. The extracted coefficient for mesons A = 0.095 ± 0.015 is indeed quite universal. The exponential suppression was applied to both strong and radiative decays. I will discuss the relation with string fragmentation and jet formation. I will extract the quarkdiquark structure of baryons from their decays. A stringy mechanism for Zweig sup pressed decays of quarkonia will be proposed and will be shown to reproduce the decay width of Υ states. The dependence of the width on spin and flavor symmetry will be discussed. We further apply this model to the decays of glueballs and exotic hadrons. 
Exceptional Seminar Sonnenschein Jacob (Tel Aviv)
at: 14:00 room H503  abstract: I will show that the nonstringy holographic description of hadrons, namely the one based on fields that reside on the bulk and flavor branes, fails to reproduce the hadronic spectra. I will briefly review the stringy duals of Wilson loops and determine the sufficient conditions of confining backgrounds. I will show that the latter are also the requirements for holographic stringy mesons to admit a Reggelike spectrum. I will determine a map between holographic stringy mesons and strings with massive endpoints in 4d flat spacetime. Models of classical rotating strings with massive endpoints will be written down. I will discuss the (still unsolved) quantization of such systems. Fits of the models to mesonic data will be presented. A universal model that describes mesons of u,d,s,c quarks will be developed. Mesons with b quarks will also be fitted. I will describe the construction of stringy baryons in holography. I will show that the best description of baryons is in terms of a single string with a quark and a diquark on its ends. I will present fits of such a model to the baryonic data. Finally I will describe the stringy decays of holographic hadrons. 
Exceptional Seminar Jacob Sonnenschein (Tel Aviv)
at: 15:30 room Blackett 630  abstract:
