Related papers: Improvement of the Theta+ width estimation method …
We report on a study of the pentaquark Theta^+(1540), using a variety of different interpolating fields. We use Chirally Improved fermions in combination with Jacobi smeared quark sources to improve the signal and get reliable results even…
To study crystals that contain heavy atoms, it is important to consider the relativistic effects, as electrons in orbitals close to the atom's nucleus can reach speeds comparable to that of light in a vacuum. In this study, we utilized the…
Here we study the quark orbital angular momentum of the ground octet baryons employing an extended chiral constituent quark model, within which the baryon wave functions are taken to be superposition of the traditional $qqq$ and the…
A chiral effective theory of quarks and diquarks is formulated and applied to exotic tetraquarks and pentaquarks. The effective theory is similar to the chiral quark effective theory with the addition of diquark degrees of freedom and…
I overview the physical picture of QCD at low energies that has led to the prediction of a narrow exotic baryon Theta^+ which cannot be made of three quarks. The very narrow width of the Theta^+ and a possible reason why it is seen in low-…
The possibility of the existence of multiquark hadrons made of 4-quark for mesons and 5-quark for baryons was predicted by Gell-Mann in Ref. [1]. The renewed interest for the search of exotic pentaquark states was initiated by the paper by…
In this paper, we apply the Maximum Entropy Method to estimate the proton radius and determine the valence quark distributions in the proton at extremely low resolution scale Q$^{2}_{0}$. Using the simplest functional form of the valence…
We use the NRQCD factorization formalism to calculate the relativistic corrections to the fragmentation function for a gluon fragmenting into a spin-triplet S-wave heavy quarkonium. We make use of the gauge-invariant formulation of the…
We derive the imaginary part of the potential NRQCD Hamiltonian up to order 1/m^4, when the typical momentum transfer between the heavy quarks is of the order of Lambda_{QCD} or greater, and the binding energy E much smaller than…
A neutron or proton excess in nuclei leads to an isovector-vector mean-field which, through its coupling to the quarks in a bound nucleon, implies a shift in the quark distributions with respect to the Bjorken scaling variable. We show that…
We analyze the existence of the exotic $\Theta^+$ from the perspective of instanton induced quark dynamics. The 't Hooft interaction gives strong attraction in specific channels of the triquark $ud\bar s$ and diquark $ud$ configurations. In…
We present the study of the semileptonic decay \Lambda_c to \Lambda\ell^+\nu by using the light-cone sum rule approach. Distribution amplitudes (DAs) for the \Lambda baryon are discussed to the leading order conformal spin, and QCD sum rule…
We calculate the contribution of relativistic dynamics on the neutron-deuteron scattering length and triton binding energy employing five sets trinucleon potential models and four types of three-dimensional relativistic three-body equations…
The cross sections for the M1-capture n + p -> D + gamma, the photo-magnetic and anti-neutrino disintegration of the deuteron are evaluated in the relativistic field theory model of the deuteron (RFMD). The cross section for M1-capture is…
We perform a QCD sum rule analysis for the pentaquark baryon Theta^+ with the non-interacting $KN$ contribution treated carefully. The coupling of the Theta^+ current to the $KN$ state is evaluated by applying the soft kaon theorem and…
The next-to-leading-order electroweak corrections to $pp\to l^+l^-/\bar\nu\nu+\gamma+X$ production, including all off-shell effects of intermediate Z bosons in the complex-mass scheme, are calculated for LHC energies, revealing the…
Prompted by the recent surprising results in QCD spectroscopy, we extend to heavy flavors the hadron mass relations showing that the constituent quark mass differences and ratios have the same values when obtained from mesons and baryons.…
If the exotic baryon $\Theta^+(1540)$ is a correlated $udud\bar{s}$ with $J^P = {1/2}^+$, then there should exist an exotic meson, $J^P = 1^-$ $\vartheta^+ (S=+2)$ $\to K^+K^0$ $\sim 1.6$GeV with width $O(10-100)$MeV. The $\pi_1(1400;1600)$…
The 1/N expansion for exotic baryons is developed, and applied to the masses, meson couplings and decay widths. Masses and widths of the 27 and 35 pentaquark states in the same tower as the Theta+ are related by spin-flavor symmetry. The 27…
In the search for the pentaquark $\Theta^+$ baryon, the world data on $K^+n\to K^+n$ and $K^+n\to K^0\,p$ reactions on the deuteron target and $K^0\,p\to K^+n$ and $K^0_L\,p\to K^0_S\,p$ reactions on the hydrogen target are revisited to…