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DOE OSTI2018

Search for Hidden-Charm Pentaquark with CLAS12

LHCb recently announced the discovery of two exotic structures in the J/?+p decay channel, which have been referred to as charmonium-pentaquark states. Resolving differences between models for these states, clarifying the nature of the discovered hidden-charm pentaquark peaks, and discovery of any similar states with other quantum numbers, will require further experimental studies. It is natural to expect that such pentaquark states should be produced in the photoproduction process ?+p-> Pc -> J/?+p, where they will appear as s-channel resonances at photon energy around 10 GeV. The energy and luminosity of the Jefferson Lab CLAS12 photon beam will permit detailed studies of the production and decay properties of such pentaquark resonances. This presentation will discuss a search for these pentaquark states which is currently underway with CLAS12.

Kubarovsky, Valery↗

DOE OSTI2024

Search for prompt production of pentaquarks in charm hadron final states

A search for hidden-charm pentaquark states decaying to a range of Σ c D ¯ and Λ c + D ¯ final states, as well as doubly charmed pentaquark states to Σ c D and Λ c + D , is made using samples of proton-proton collision data corresponding to an integrated luminosity of 5.7 fb − 1 recorded by the LHCb detector at s = 13 TeV . Since no significant signals are found, upper limits are set on the pentaquark yields relative to that of the Λ c + baryon in the Λ c + → p K − π + decay mode. The known pentaquark states are also investigated, and their signal yields are found to be consistent with zero in all cases. © 2024 CERN, for the LHCb Collaboration 2024 CERN

Aaij, R. (ORCID:0000000305331952)↗

DOE OSTI2021

The J/ψ-007 Experiment: A Search for the LHCB Charm Pentaquarks in Hall C at Jefferson Lab

In the Jefferson Lab E12-16-007 (J/ψ- 007) experiment we measured the differential J/ψ photo-production cross section as a function of photon energy, Ey and Mandelstam variable t- the momentum transfer from the initial photon to the produced J/ψ- in the energy region where all the charm pentaquark states were discovered by the LHCb (Large Hadron Collider beauty) collaboration. The J/ψ-007 experiment was conducted in the experimental Hall C of the Thomas Jefferson National Accelerator Facility using a high-intensity real photon beam generated by a 10.6 GeV incident electron beam traversing a copper radiator upstream of a liquid hydrogen target. Two arm spectrometers of Hall C, HMS (High Momentum Spectrometer), and SHMS (Super High Momentum Spectrometer) were used to detect the e + e - dilepton J/ψ decay pairs in coincidence. The spectrometers' four momentum and angle settings scanned a photon beam energy range between 9.1 and 10.6 GeV and |t| up to 5 GeV 2 . An enhanced sensitivity to the s-channel resonant J/ψ photo-production was achieved by optimizing the spectrometer settings at a higher t region where the non-resonant standard t-channel J/ψ production cross section is strongly suppressed. No evidence for pentaquarks was observed and, the cross section upper limits for each LHCb pentaquark candidate were determined and are presented in this document.

Duran, Burcu↗

DOE OSTI2021

Fine structure of pentaquark multiplets in the dynamical diquark model

In this work, we apply the dynamical diquark model to predict the spectrum of hidden-charm pentaquark states in both unflavored and open-strange sectors. Using only Hamiltonian parameters introduced in the tetraquark S - and P -wave multiplets, the model naturally produces the level spacing supported by the most recent LHCb results for P c structures. Furthermore, using model inputs obtained from data of hidden-charm, open-strange tetraquarks ( Z c s ), we predict the spectrum of P c s states, including the recently observed P c s ( 4459 ) . We find all pentaquark candidates observed to date to belong to the 1 P multiplet and hence have positive parity.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2020

Hidden-charm and bottom tetra- and pentaquarks with strangeness in the hadro-quarkonium and compact tetraquark models

In two recent papers, we used the hadro-quarkonium model to study the properties of hiddencharm and bottom tetraquarks and pentaquarks. Here, we extend the previous results and calculate the masses of heavy-quarkonium-kaon/hyperon systems. We also compute the spectrum of hiddencharm and bottom tetraquarks with strangeness in the compact tetraquark (diquark-antidiquark) model. If heavy-light exotic systems with non-null strangeness content were to be observed experimentally, it might be possible to distinguish among the large variety of available theoretical pictures for tetra- and pentaquark states and, possibly, rule out those which are not compatible with the data.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2025

Pentaquarks made of light quarks and their admixture to baryons

This paper is a continuation of our studies of multiquark hadrons. The antisymmetrization of their wave functions required by Fermi statistics is nontrivial, as it mixes orbital, color, spin, and flavor structures. In our previous papers we developed a method to find them based on the representations of the permutation group, and derived the explicit wave functions for baryons excited to the first and second shells (L = 1, 2), tetraquarks $qq$$\overline{q}$$\overline{q}$ and hexaquarks (6q). Now we apply it to light pentaquarks ($qqq$$\overline{q}$), in the S- and P-shells (L = 0, 1). Using Jacobi coordinates, one can use the hyperdistance approximation in 12-dimensional space. We further address the issue of “unquenching” of baryons, by considering their mixing with pentaquarks, via two channels, through the addition of σ-like or π-like $\overline{q}$$q$ pairs. This mixing is central for understanding of the observed flavor asymmetry of the antiquark sea, the amount of orbital motion issue as well as other nucleon properties.

Baryons↗

DOE OSTI2018

Search for weakly decaying b -flavored pentaquarks

Investigations of the existence of pentaquark states containing a single b (anti)quark decaying weakly into four specific final states J/ψK + π – p, J/ψK – π – p, J/ψK – π + p, and J/ψΦ(1020)p are reported. The data sample corresponds to an integrated luminosity of 3.0 fb –1 in 7 and 8 TeV pp collisions acquired with the LHCb detector. Signals are not observed and upper limits are set on the product of the production cross section times branching fraction with respect to that of the Λ 0 b .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2023

Observation of a J / ψ Λ Resonance Consistent with a Strange Pentaquark Candidate in B - → J / ψ Λ p ¯ Decays

An amplitude analysis of Β - → J/ψ⁢Λ⁢$\overline{p}$ decays is performed using 4400 signal candidates selected on a data sample of pp collisions recorded at center-of-mass energies of 7, 8, and 13 TeV with the LHCb detector, corresponding to an integrated luminosity of 9 fb -1 . A narrow resonance in the J/ψ⁢Λ system, consistent with a pentaquark candidate with strangeness, is observed with high significance. The mass and the width of this new state are measured to be 4338.2±0.7±0.4 MeV and 7.0±1.2±1.3 MeV, where the first uncertainty is statistical and the second systematic. The spin is determined to be 1/2 and negative parity is preferred. Because of the small Q-value of the reaction, the most precise single measurement of the B- mass to date, 5279.44±0.05±0.07 MeV, is obtained.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2019