Jun 2 – 7, 2019
Carnegie Mellon University
America/New_York timezone

## New results on Nucleon/Baryon Timelike Form Factors

Jun 4, 2019, 5:30 PM
30m
Rangos 3

### Rangos 3

Contributed Nucleon Structure

### Speaker

Prof. Marco Maggiora (Department of Physics, University of Turin and INFN, Turin)

### Description

An important tool to study the Nucleon Structure are the Nucleon/Baryon Timelike Form Factors.

Many unexpected features have recently been found by BESIII and other experiments concerning $e^+e^-\rightarrow N \bar{N}$ as well as $e^+e^-\rightarrow B \bar{B}$, close to their thresholds, like for instance:

• oscillations in the Proton Timelike Effective Form Factor as a
function of the energy;
• steep steps in the cross section at threshold followed by a
plateau in $e^+e^-\rightarrow p \bar{p}$, as well as in $e^+e^-\rightarrow \Lambda_c \bar{\Lambda_c}$ and simiiar behaviour in other $e^+e^-\rightarrow B \bar{B}$ cross sections.

Data will be shown and possible interpretations discussed.
Concerning the near future, some features of $e^+e^-\rightarrow \Lambda_c \bar{\Lambda_c}$ will be reported, that might be related to the recently found XYZ new resonances, if interpreted as four quarks states.
BESIII will collect more data above the maximum energy, achieved at present.