Related papers: Pentaquark Searches
We find that several thresholds can contribute to the enhancements of the newly observed heavy pentaquark candidates $P_c^+(4380)$ and $P_c^+(4450)$ via the anomalous triangle singularity (ATS) transitions in the specific kinematics of…
If the recently discovered anomalous events at HERA are due to a scalar leptoquark, then it is very likely to have weak isospin $I = 1/2$. In that case, present precision measurements of the oblique radiative parameters $S$ and $T$ provide…
The 2015 LHCb discovery of a structure (denoted by $P_c^+$) decaying in $J/\psi \,p$ and conjectured to be a penta-quark state, has triggered a renewed interest in the question of possible existence of multi-quark states not predicted by…
If the Theta^+(1540) is interpreted as a bound state of a $\bar s$ quark and two (ud) diquarks in a relative P-wave, then it is very likely that there exist pentaquark states with a heavy antiquark, $\bar b$ or $\bar c$, and two ``light''…
The past decade witnessed the observation of several exotic charmonium-like resonances, some of which are manifestly non-qqbar mesons. We review one of the most popular interpretations of such states: the compact tetraquark in the…
We have investigated uudd\sbar pentaquarks by employing quark models with the meson exchange and the effective gluon exchange as qq and q\qbar interactions. The system for five quarks is dynamically solved; two quarks are allowed to have a…
This paper has been withdrawn by the author(s). Please see arXiv:0711.3910 for revision.
We have investigated negative-parity uudd\bar{s} pentaquarks by employing a quark model with the meson exchange and the effective gluon exchange as qq and q\bar{q} interactions. The system for the five quarks is dynamically solved; the…
We discuss the differences between several partial-wave analysis formalisms used in the construction of three-body decay amplitudes involving fermions. Specifically, we consider the decay Lambda_b -> psi p K- , where the hidden charm…
We analyze the possible existence of a strangeness $S=-3$, isospin $I=1$ pentaquark state $P_{sss}$ generated dynamically from the $\bar{K}\Xi$ interaction. We employ a unitarized scheme in coupled channels based on the chiral Lagrangian…
Data for magnetic moments and semileptonic decays show disagreements between experimental values and theoretical predictions not easily explained by simple models for $\Lambda$ and $\Sigma$ hyperons.
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…
The K0s-p invariant mass spectrum was reconstructed in several kinematic regions with the main emphasis on the studies of the production mechanism of the Theta+ candidate recently observed by ZEUS. The candidate Theta+ signal was found to…
The relativistic five-quark equations are found in the framework of the dispersion relation technique. The five-quark amplitudes for the low-lying pentaquarks including the u,d,s-quarks are calculated. The poles of these amplitudes…
We use a constituent model to analyze the stability of pentaquark $\bar Q qqqq$ configurations with a heavy antiquark $\bar c$ or $\bar b$, and four light quarks $uuds$, $ddsu$ or $ssud$. The interplay between chromoelectric and…
An earlier four-loop calculation of the fluctuation pressure of a fluid membrane between two infinite walls is extended to five loops. Variational perturbation theory is used to extract the hard-wall limit from perturbative results obtained…
In this review there is first a survey of the HERA data. Then we discuss the theory response including querying the consistency of the data, compositeness, contact terms, and leptoquarks including as a special case the R symmetry violating…
Statistical fluctuation problems are faced by all quantum key distribution (QKD) protocols under finite-key condition. Most of the current statistical fluctuation analysis methods work based on independent random samples, however, the…
In recent years, many tetraquarks and pentaquarks have been discovered by various experimental groups and X(3872), Zc(3900), X(4430), P + c (4312), P + c (4457) are some of the interesting observed tetraquark and pentaquark states. The…
We use a theoretical model of the $\gamma ~d \to ~K^+ K^- ~n ~p $ reaction adapted to the experiment done at LEPS where a peak was observed and associated to the $\Theta^{+}(1540)$ pentaquark. The study shows that the method used in the…