Found 3 result(s)

### 14.09.2017 (Thursday)

#### The decay width of stringy hadrons

Exceptional Seminar Jacob Sonnenschein (Tel Aviv University)

 at: 14:00 ICroom 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 quark-diquark 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.

### 13.10.2014 (Monday)

#### Holographic stringy hadrons

Exceptional Seminar Sonnenschein Jacob (Tel Aviv)

 at: 14:00 ICroom H503 abstract: I will show that the non-stringy 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 Regge-like spectrum. I will determine a map between holographic stringy mesons and strings with massive endpoints in 4d flat space-time. 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 di-quark 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.

### 26.08.2009 (Wednesday)

#### Holographic Baryons

Exceptional Seminar Jacob Sonnenschein (Tel Aviv)

 at: 15:30 ICroom Blackett 630 abstract: