# The Rise and Fall of Pentaquarks in Experiments

@article{Schumacher2006TheRA,
title={The Rise and Fall of Pentaquarks in Experiments},
author={R. Schumacher},
journal={arXiv: Nuclear Experiment},
year={2006},
volume={842},
pages={409-417}
}
Experimental evidence for and against the existence of pentaquarks has accumulated rapidly in the last three years. If they exist, they would be dramatic examples of hadronic states beyond our well‐tested and successful particle models. The positive evidence suggests existence of baryonic objects with widths of at most a few MeV, some displaying exotic quantum numbers, such as baryons with strangeness S = +1. The non‐observations of these states have often come from reaction channels very… Expand
12 Citations

#### Figures from this paper

Constituent Counting Rules and Exotic Hadrons
The constituent counting rules, i.e., the scaling behavior of amplitudes (in terms of the number of fundamental constituents) for exclusive processes when high energy scales are present, have beenExpand
Nonstandard heavy mesons and baryons: Experimental evidence
• Physics
• 2018
Quantum chromodynamics (QCD), the generally accepted theory for strong interactions, describes the interactions between quarks and gluons. The strongly interacting particles that are seen in natureExpand
Searches for New Physics at the Large Hadron Collider
The experiments currently underway at the Large Hadron Collider are exploring the physics of the TeV energy scale, which may hold the answers to some of the most profound questions in particleExpand
• Physics
• 2007
Detailed investigations of the structure of hadrons are essential for understanding how matter is constructed from the quarks and gluons of Quantum chromodynamics (QCD), and amongst the questionsExpand
K* production in the KN → Kπp reaction *
• Physics
• 2020
We investigate the production in the reaction using the effective Lagrangian approach and the isobar model. To describe this reaction, we first take into account the contributions from the , andExpand
Search for a pentaquark decaying to Cascade- pi-
• Physics
• 2007
We present a search for a pentaquark decaying strongly to $\Xi^-\pi^-$ in $\gamma N$ collisions at a center-of-mass energy up to 25 GeV/c^2. Finding no evidence for such a state in the mass range ofExpand
Search for a pentaquark decaying to Ξ−π−
• Physics
• 2006
Abstract We present a search for a pentaquark decaying strongly to Ξ − π − in γN collisions at a center-of-mass energy up to 25 GeV / c 2 . Finding no evidence for such a state in the mass range ofExpand
LIGHT QUARK SPECTROSCOPY
This report summarizes the results in light quark spectroscopy achieved in last few years. The variety of experimental approaches, from kaon decays to fix target experiments and high statisticsExpand
Baryon spectrum in large N{sub c} chiral soliton and in quark models
• Physics
• 2006
Strangeness contents of baryons are calculated within the rigid rotator model for arbitrary number of colors N{sub c}. The problem of extrapolation to realistic value N{sub c}=3 is noted, based onExpand
Search for Σ(5)(0), N(5)(0), and Θ++ Pentaquark States
• Physics
• 2007
A high-resolution (σinstr.=1.5 MeV) search for narrow states (Γ<10 MeV) with masses of Mx≈1500–1850 MeV in ep→e′K+X,e′K-X, and e′π+X electroproduction at small angles and low Q2 was performed. TheseExpand

#### References

SHOWING 1-10 OF 121 REFERENCES
Search for Pentaquarks at BABAR
The results of searches for the strange pentaquark states, Theta(1540)+, Xi(1860)-- and Xi(1860)0 in data recorded by the BABAR experiment are presented. We search for these three states inclusivelyExpand
Recent results on searches for pentaquark states from STAR at RHIC
We present results on pentaquark searches from nuclear collisions at RHIC with the STAR detector system. An intriguing peak has been observed in the invariant mass distribution of from 18.6 MillionExpand
Evidence for a narrow baryonic state decaying to K 0 S p and K 0 S p̄ in deep inelastic scattering
A resonance search has been made in the K S p and K 0 S p̄ invariant-mass spectrum measured with the ZEUS detector at HERA using an integrated luminosity of 121 pb. The search was performed in theExpand
Evidence for the positive-strangeness pentaquark Θ+ in photoproduction with the SAPHIR detector at ELSA
• Physics
• 2003
Abstract The positive-strangeness baryon resonance Θ + is observed in photoproduction of the nK + K 0 s final state with the SAPHIR detector at the Bonn ELectron Stretcher Accelerator ELSA. It isExpand
Observation of a narrow baryon resonance decaying to pKS0 in proton-nucleus interactions at 70 GeV/c with the SVD-2 setup
AbstractData from the SVD-2 experiment that were obtained at the IHEP accelerator in 70-GeV/c proton-nucleus interactions are analyzed with the aim of searches for an exotic Θ+ baryon that decaysExpand
Evidence for a narrow anti-charmed baryon state
AbstractWe report an observation of a narrow resonance state inD*− andD*+ $$\bar p$$ in inelastic electron-proton collisions at centre-of-mass energies of 300 and 320 GeV at HERA. The resonance hasExpand
Evidence for a narrow |S |= 1 baryon state at a mass of 1528 MeV in quasi-real photoproduction
• Physics
• 2004
Abstract Evidence for a narrow baryon state is found in quasi-real photoproduction on a deuterium target through the decay channel pK0S→pπ+π−. A peak is observed in the pK0S  invariant mass spectrumExpand
Diquarks and exotic spectroscopy.
• Physics, Medicine
• Physical review letters
• 2003
It is proposed that the recently discovered Theta(+) baryon is a bound state of four quarks and an antiquark, containing two highly correlated ud pairs, and it lies in an near-ideally mixed SU(3)(f) 10;(f) plus sign in circle 8(f). Expand
Observation of an exotic S = +1 baryon in exclusive photoproduction from the deuteron.
In an exclusive measurement of the reaction gammad-->K(+)K(-)pn, a narrow peak that can be attributed to an exotic baryon with strangeness S=+1 is seen in the K(+)n invariant mass spectrum. The peakExpand
Observation of an exotic baryon with S=+1 in photoproduction from the proton.
The reaction gamma p-->pi(+)K(-)K(+)n was studied at Jefferson Laboratory using a tagged photon beam with an energy range of 3-5.47 GeV. A narrow baryon state with strangeness S=+1 and massExpand