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M. Sadzikowski

Publications and source records attributed to M. Sadzikowski.

17 recordsLinked to original sources
arXiv2012

Evidence for breakdown of the DGLAP description in diffractive DIS at HERA

HERA data on diffractive DIS show deviations from twist 2 DGLAP predictions below $Q^2\sim 5$ GeV$^2$ at low pomeron $ξ$, which may reach up to 100%. These deviations are consistent with higher twists effects extracted from the saturation model. It is a first direct evidence for the higher twists in DIS. This finding affects determination of the diffractive parton densities that are used for the predictions at the LHC.

hep-ph↗
arXiv2012

Evidence for the higher twists effects in diffractive DIS at HERA

We study a twist decomposition of diffractive structure functions in the diffractive deep inelastic scattering at HERA. At low $Q^2$ and at large energy the data exhibit a strong deviation from the twist-2 NLO DGLAP description. It is found that this deviation in consistent with higher twist effects. We conclude that the DDIS at HERA provides the first, strong evidence of higher twist effects in DIS.

hep-ph↗
arXiv2012

Evidence of strong higher twist effects in diffractive DIS at HERA at moderate Q2

We study a twist decomposition of diffractive structure functions in the diffractive deep inelastic scattering (DDIS) at HERA. At low Q2 and at large energy the data exhibit a strong excess, up to about 100%, above the twist 2 NLO DGLAP description. The excess in consistent with higher twist effects. It is found, that complementing the DGLAP fit by twist 4 and 6 components of the GBW saturation model leads to a good description of data at low Q2. We conclude that the DDIS at HERA provides the first, strong evidence of higher twist effects in DIS.

hep-ph↗
arXiv2010

Andreev reflection between a normal metal and the FFLO superconductor II: a self-consistent approach

We consider Andreev reflection in a two dimensional junction between a normal metal and a heavy fermion superconductor in the Fulde-Ferrell (FF) type of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state. We assume s-wave symmetry of the superconducting gap. The parameters of the superconductor: the gap magnitude, the chemical potential, and the Cooper pair center-of-mass momentum Q, are all determined self-consistently within a mean-field (BCS) scheme. The Cooper pair momentum Q is chosen as perpendicular to the junction interface. We calculate the junction conductance for a series of barrier strengths. In the case of incoming electron with spin σ= 1 only for magnetic fields close to the upper critical field H_{c2}, we obtain the so-called Andreev window i.e. the energy interval in which the reflection probability is maximal, which in turn is indicated by a peak in the conductance. The last result differs with other non-self-consistent calculations existing in the literature.

cond-mat.supr-con↗
arXiv2003

The masses of $D_{sj}^\ast$(2317) and $D_{sj}^\ast$(2463) in the MIT bag model

The masses of the $D_{sj}^\ast$(2317)and $D_{sj}^\ast$(2463) were found in the MIT bag model in a reasonable agreement with the experimental values. The spectrum of ${0^\pm,1^\pm}$ for $D$ and $B$ mesons is presented. The equalities between the mass splittings $(1^+ - 1^-)(c\bar{q})\approx (1^+ - 1^-)(c\bar{s})$ and $(0^+ - 0^-)(c\bar{q})\approx (0^+ - 0^-)(c\bar{s})$, where $q=u, d$ are confirmed despite of the fact that $SU(3)_L\times SU(3)_R$ chiral symmetry is broken by the non-zero strange quark mass.

hep-ph↗
arXiv2003

Superconducting phase transition in the Nambu - Jona-Lasinio model

The Nambu - Bogoliubov - de Gennes method is applied to the problem of superconducting QCD. The effective quark-quark interaction is described within the framework of the Nambu - Jona-Lasinio model. The details of the phase diagram are given as a function of the strength of the quark-quark coupling constant $G^{\prime}$. It is find that there is no superconducting phase transition when one uses the relation between the coupling constants $G^{\prime}$ and $G$ of the Nambu - Jona-Lasinio model which follows from the Fierz transformation. However, for other values of $G^{\prime}$ one can find a rich phase structure containing both the chiral and the superconducting phase transitions.

hep-ph↗
arXiv2002

Andreev reflection at QGP/CFL interface

In this letter we address the question of the phenomena of Andreev reflection between the cold quark-gluon plasma phase and CFL color superconductor. We show that there are two different types of reflections connected to the structure of the CFL phase. We also calculate the probability current at the interface and we show that it vanishes for energy of scattering quarks below the superconducting gap.

hep-ph↗
arXiv2002

Quark scattering at QGP/2SC interface

We considered the phenomenon of the Andreev reflection of quarks at the interface between the cold quark-gluon plasma phase and 2SC color superconductor.

hep-ph↗
arXiv1998

Antibaryon density in the central rapidity region of a heavy ion collision

We consider (anti-)baryons production in heavy ion collisions as production of topological defects during the chiral phase transition. Non-zero quark masses which explicitly break chiral symmetry supress the (anti-)baryon density. Hardly any (anti-)baryons will be produced in the central rapidity region of a heavy ion collision.

hep-ph↗
arXiv1998

Quantum radiation from spherical mirrors

We consider mirrors of the spherical shape, that can expand or contract. Due to the excitation of the vacuum around, some spherical waves radiated from vibrating mirrors are encountered. Using experience from well-known literature on studies of two-dimensional conformal models, we adopt a similar framework to investigate such quantum phenomena in four dimensions. We calculate quantum averages of the energy-momentum tensor for s-wave approximation.

hep-th↗
arXiv1997

Exclusive $η_c$ photo- and electroproduction at HERA as a possible probe of the odderon singularity in QCD

Theory and phenomenology of the eta_c photo- and electroproduction is developed from the point of view of probing the odderon singularity in QCD which corresponds to the three gluon exchange mechanism. This mechanism leads to the cross-sections which are independent of W^2 for the exchange of three non-interacting gluons or exhibit increase with increasing W^2 (or 1/x) for the odderon intercept above unity. The η_c electroproduction in the three gluon exchange mechanism is shown to be entirely controlled by the transversely polarised virtual photons. The magnitude of the eta_c photoproduction cross-section is estimated to be around 11-45pb. The t-dependence of the differential cross-section is also discussed.

hep-ph↗
arXiv1996

Meson bound states in multiflavour massive Schwinger model

The problem of meson bound states with $N_f$ massive fermions in two dimensional quantum electrodynamics is discussed. We speculate about the spectrum of the lightest particles by means of the effective semiclassical description. In particular, the systems of fundamental fermions with $SU(2)$ and $SU(3)$ flavour symmetries broken by massive terms are investigated.

hep-ph↗
arXiv1994

Semileptonic Decays of Heavy to Light Mesons from an Mit Bag Model

Using the (modified) MIT bag model we calculated formfactors and decay widths for pseudoscalar - pseudoscalar and pseudoscalar - vector semileptonic decays of heavy to light mesons. We discuss the physical phenomena which are important in these processes and their influence on the measurable quantities. Our results are consistent with the available experimental data. A comparison with the results of other models is also given.

hep-ph↗
arXiv1994

Isgur - Wise Functions for Confined Light Quarks in a Colour Electric Potential

We explore the influence on the Isgur-Wise function of the colour electric potential between heavy and light quarks in mesons. It is shown that in bag models, its inclusion tends to restore light quark flavour symmetry relative to the MIT bag predictions, and that relative to this model it flattens the Isgur-Wise function. Results compare very well with observations.

hep-ph↗
arXiv1993

Isgur-Wise Functions from the Mit Bag Model

The Isgur-Wise functions for the ground state to ground state semileptonic decays involving $b \rightarrow c$ transitions are calculated from the (modified) MIT bag model. It is checked that the results for the decays $\overline{B} \rightarrow D l \overlineν$ and $\overline{B} \rightarrow D^* l \overlineν$ agree well with experiment. Predictions for the decays $Λ_b \rightarrow Λ_c l \overlineν$, $\overline{B}_s \rightarrow D_s l \overlineν$ and $\overline{B}_s \rightarrow D^*_s l \overlineν$ are given and discussed.

hep-ph↗