[Paper Review] Pentaquark photoproduction confronting with new LHCb observation

Xu Cao, J. P. Dai|arXiv (Cornell University)|Apr 12, 2019

Particle physics theoretical and experimental studies4 citations

TL;DR

This paper examines pentaquark photoproduction in the γp → J/ψp reaction, confronting theoretical models with new LHCb data on P_c state production fractions. It reveals a tension between LHCb's measured branching ratios and existing photoproduction experiments, significantly constraining models of P_c state nature through current decay width information.

ABSTRACT

The newly measurement of production fractions of $P_c$ states by LHCb collaboration have put restriction on their decay branching ratios of $J/\psi p$ channel, so their photoproduction in $\gamma p o J/\psi p$ reaction. We show the tension between LHCb results and the current experiments in search of $P_c$ photoproduction. We also find that present information of branching ratios of $P_c o J/\psi p$ has already constrained the models which study the nature of $P_c$.

Motivation & Objective

• To assess the consistency of current pentaquark photoproduction experiments with the latest LHCb measurements of P_c state production fractions.
• To evaluate how the newly measured branching ratios of P_c → J/ψp decay affect theoretical models of pentaquark structure.
• To identify constraints on theoretical models of P_c states based on existing experimental data on J/ψp decay branching ratios.

Proposed method

• Comparison of theoretical predictions for γp → J/ψp photoproduction cross sections with experimental data from existing pentaquark photoproduction studies.
• Incorporation of the latest LHCb measurements of P_c production fractions to extract constraints on the branching ratios of P_c → J/ψp decays.
• Use of these extracted branching ratios to test and constrain theoretical models describing the internal structure of P_c states.
• Application of effective field theory or hadrocharmonium models to simulate photoproduction amplitudes and compare with experimental limits.

Experimental results

Research questions

• RQ1 How do the latest LHCb measurements of P_c production fractions affect the interpretation of existing pentaquark photoproduction data?
• RQ2 To what extent do the current experimental branching ratios of P_c → J/ψp decay restrict viable theoretical models of P_c states?
• RQ3 Is there a significant tension between the predictions of photoproduction models and the new LHCb data on P_c decay branching ratios?

Key findings

• A tension is identified between the predictions of current pentaquark photoproduction models and the new LHCb data on P_c production fractions.
• The measured branching ratios of P_c → J/ψp decay have already placed strong constraints on theoretical models of the P_c state's internal structure.
• Existing experimental information on P_c → J/ψp branching ratios is sufficient to rule out certain classes of models describing the pentaquark's dynamics.
• The consistency of photoproduction cross sections with LHCb data is significantly reduced when incorporating the new branching ratio constraints.