相关论文: Pentaquarks: review of the experimental evidence
We review and discuss the experimental evidence on predicted baryonic states made by 4 quarks and one antiquark, called pentaquarks. Theoretical and experimental advances in the last few years led to the observation of pentaquark candidates…
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…
The pentaquarks are exotic baryons formed of four quarks and an antiquarks. Their existence has been discussed in the literature over the last 30 years or more, first in connection with kaon nucleon scattering data. The subject has been…
A review is given of the theoretical ideas concerning the mysterious pentaquark baryons proposed during the first year after its discovery. We focus on the difficulties involved with the constituent quark models and the discrepancy between…
The experimental evidence for pentaquarks is reviewed and compared with the experiments that do not see any sign of pentaquarks.
The experimental evidence for pentaquarks, both old an new, is discussed. Constraints due to $K^+N$ scattering data from previous decades is first reviewed, followed by experiments with positive evidence and those with null results.…
Pentaquark baryons are a natural expectation of an extended picture of hadrons where quarks and diquarks are the fundamental units. The parity/mass pattern observed, when compared to that of exotic mesons, appears as the footprint of a…
The strange-anticharmed Pentaquark is a uud(cbar)s or udd(cbar)s five-quark baryon that is expected to be either a narrow resonance, or possibly even stable against strong decay. We describe this hyperon here; its structure, binding energy…
It has been ten years since the first report for a positive strangeness pentaquark-like baryon state. However the existence of the pentaquark state is still controversial. Some contradictions between the experiments are unsolved. In this…
The present experimental evidence for the existence of light pentaquarks is reviewed, including both positive and null results. I also discuss the CLAS experiments at Jefferson Laboratory that are forthcoming in the near future to address…
The strange-anticharmed Pentaquark is a $uud\bar{c}s$ or $udd\bar{c}s$ five-quark baryon that is expected to be either a narrow resonance, or possibly even stable against strong and electromagnetic decay. We describe this hyperon here, its…
Several experimental groups have reported evidence for baryons with flavor exotic quantum numbers that cannot be explained as $qqq$ bound states but require a minimum of five quarks -- $qqqq \bar q$. These pentaquark states include the…
Recent evidence for pentaquark baryons is critically reviewed in the light of new high statistics data. The search of the WA89 experiment for the $\Xi^{--}(1860)$ is presented in detail and consequences of its non-observations are…
The status of the search for pentaquark baryons is reviewed in light of new results from the first two dedicated experiments from CLAS at Jefferson Lab and of new analyses from several laboratories on the $Theta^+(1540)$. Evidence for and…
Since LEPS collaboration reported the first evidence of $\Theta^+$ pentaquark in early 2003, eleven other experimental groups have confirmed this exotic state while many other groups didn't see any signal. If this state is further…
Is there a theory or good experimental evidence? Bj's question: Pentaquark is created by $e^+e^-$. $2q + q \to$ Baryon $; ~ ~ ~ 2q + \bar q \to $ Triquark$ ; ~ ~ ~ 2q + $Triquark $ \to $Pentaquark Does it live long onough to be observable?…
Evidence for the $\Theta^+$ pentaquark is still sketchy at the present time. This state, if it exists, has a small width and consequently a small production cross section. No single experiment has overwhelming evidence for the $\Theta^+$…
I first give a brief overview of the status of exotic hadron search so far. Then I review the recent theoretical development on pentaquarks. Finally I emphasize that none of theoretical formalisms predicts the existence of $\Theta$…
Multiquark resonances are undoubtedly experimentally observed. The number of states and the amount of details on their properties has been growing over the years. It is very recent the discovery of two pentaquarks and the confirmation of…
The existence of an anti-decuplet of pentaquark particles has been predicted some year ago within the chiral soliton model. In the last year, several experimental groups have reported evidence for a S=+1 baryon resonance, with mass ranging…