arXiv subjects

Maxim V. Polyakov

Publications and source records attributed to Maxim V. Polyakov.

45 records · Page 3Linked to original sources

arXiv2008

Dual parameterization and Abel transform tomography for twist-3 DVCS

We derive dual parameterization for the DVCS amplitude to the twist-3 accuracy. The relation of the dual parameterization to the Abel transform tomography for amplitudes of hard exclusive processes is elaborated. We prove dispersion relations for the twist-3 DVCS amplitude in the Wandzura -- Wilczek approximation and show that the subtraction constant is given by the D-term form factor. The same as in the case of twist-2 DVCS amplitude.

hep-ph↗

arXiv2006

To see the exotic Theta^+ baryon from interference

Since all couplings of the exotic $Θ^+$ baryon to normal hadrons seem to be small it is hard to reveal it in standard resonance searching. We suggest to look for the $Θ^+$ production in interference with a known resonance yielding the same final state but having a high production rate. The interference process is linear in the $Θ^+$ couplings whereas the non-interference process is quadratic. That gives an obvious gain if the couplings are small. Moreover, employing the peculiar oscillating nature of the interference processes one can reduce considerably the parasitic background and determine the $Θ^+$ resonance parameters.

hep-ph↗

arXiv2006

Soft Pion Emission in Hard Exclusive Pion Production

We investigate hard exclusive reactions on the nucleon with soft pion emission. A parametrization of corresponding hadronic matrix elements in terms of parton distributions for final pion-nucleon state is provided. These distributions are calculated in terms of nucleon and pion GPDs and the pion distribution amplitude via soft-pion theorems. Some observables for the process of hard charged pion production on the proton with soft pion emission are computed.

hep-ph↗

arXiv1998

Flavor structure of the octet magnetic moments

We use the chiral quark-soliton model to identify all symmetry breaking terms linear in $m_{s}$ and investigate the strange magnetic moment in a ``model-independent'' way. Assuming hedgehog symmetry and employing the collective quantization, we obtain the most general expression for the flavor-singlet and flavor-octet magnetic moments in terms of seven independent parameters. Having fitted these parameters to the experimental magnetic moments of the octet baryons, we show that the strange magnetic moment turns out to be positive. The best fit obtained by minimizing $χ^2$ assuming 15% theoretical accuracy yields: $μ^{({\rm s})}_{N} = (0.41 \pm 0.18) μ_{N}$.

hep-ph↗

arXiv1997

Semileptonic decay constants of octet baryons in the chiral quark-soliton model

Based on the recent study of the magnetic moments and axial constants within the framework of the chiral quark-soliton model, we investigate the baryon semileptonic decay constants $(f_1,f_2)$ and $(g_1, g_2)$. Employing the relations between the diagonal transition matrix elements and off-diagonal ones in the vector and axial-vector channels, we obtain the ratios of baryon semileptonic decay constants $f_2/f_1$ and $g_1/f_1$. The $F/D$ ratio is also discussed and found that the value predicted by the present model naturally lies between that of the Skyrme model and that of the nonrelativistic quark model. The singlet axial constant $g^{(0)}_A$ can be expressed in terms of the $F/D$ ratio and $g^{(3)}_A$ in the present model and turns out to be small. The results are compared with available experimental data and found to be in good agreement with them. In addition, the induced pseudotensor coupling constants $g_2/f_1$ are calculated, the SU(3) symmetry breaking being considered. The results indicate that the effect of SU(3) symmetry breaking might play an important role for some decay modes in hyperon semileptonic decay.

hep-ph↗

arXiv1997

Weak electricity of the Nucleon in the Chiral Quark-Soliton Model

The induced pseudotensor constant (weak electricity) of the nucleon is calculated in the framework of the chiral quark soliton model. This quantity originates from the G-parity violation and hence is proportional to $m_u-m_d$. We obtain for $m_u-m_d=-5 MeV$ a value of $g_T/g_A =-0.0038$.

hep-ph↗

arXiv1996

Tensor Charges of the Nucleon in the SU(3) Chiral Quark Soliton Model

The tensor charges of the nucleon are calculated in the framework of the SU(3) chiral quark soliton model. The rotational $1/N_c$ and strange quark mass corrections are taken into account up to linear order. We obtain the following numerical values of the tensor charges: $δu=1.12$, $δd=-0.42$, and $δs=-0.008$. In contrast to the axial charges, the tensor charges in our model are closer to those of the nonrelativistic quark model, in particular, the net number of the transversely polarized strange quarks in a transversely polarized nucleon $δs$ is compatible with zero.

hep-ph↗

arXiv1996

Nucleon Tensor Charges in the SU(2) Chiral Quark--Soliton Model

We investigate the singlet $g_T^{(0)}$ and isovector $g_T^{(3)}$ tensor charges of the nucleon, which are deeply related to the first moment of the leading twist transversity quark distribution $h_1(x)$, in the SU(2) chiral quark-soliton model. With rotational $O(1/N_c)$ corrections taken into account, we obtain $g_T^{(0)}=0.69$ and $g_T^{(3)}=1.45$ at a low normalization point of several hundreds MeV. Within the same approximation and parameters the model yields $g_A^{(0)}=0.36$, $g_A^{(3)}=1.21$ for axial charges and correct octet--decuplet mass splitting. We show how the chiral quark-soliton model interpolates between the nonrelativistic quark model and the Skyrme model.

hep-ph↗

arXiv1995

Electromagnetic Form Factors of the SU(3) Octet Baryons in the semibosonized SU(3) Nambu-Jona-Lasinio Model

The electromagnetic form factors of the SU(3) octet baryons are investigated in the semibosonized SU(3) Nambu--Jona-Lasinio model (chiral quark-soliton model). The rotational $1/N_c$ and strange quark mass corrections in linear order are taken into account. The electromagnetic charge radii of the nucleon and magnetic moments are also evaluated. It turns out that the model is in a remarkable good agreement with the experimental data.

hep-ph↗