arXiv subjects

Michal Praszalowicz

Publications and source records attributed to Michal Praszalowicz.

At least 55 records · Page 3Linked to original sources

arXiv2013

Generalized Skyrmions in QCD and the Electroweak Sector

We discuss the stability and masses of topological solitons in QCD and strongly-interacting models of electroweak symmetry breaking with arbitrary combinations of two inequivalent Lagrangian terms of fourth order in the field spatial derivatives. We find stable solitons for only a restricted range of the ratio of these combinations, in agreement with previous results, and we calculate the corresponding soliton masses. In QCD, the experimental constraints on the fourth-order terms force the soliton to resemble the original Skyrmion solution. However, this is not necessarily the case in strongly-interacting models of electroweak symmetry breaking, in which a non-Skyrmion-like soliton is also possible. This possibility will be constrained by future LHC measurements and dark matter experiments. Current upper bounds on the electroweak soliton mass range between 18 and 59 TeV, which would be reduced to 4.6 to 8.1 TeV with the likely sensitivity of LHC data to the fourth-order electroweak Lagrangian parameters.

hep-ph↗

arXiv2013

Quantitative Study of Different Forms of Geometrical Scaling in Deep Inelastic Scattering at HERA

We use recently proposed method of ratios to assess the quality of geometrical scaling in deep inelastic scattering for different forms of the saturation scale. We consider original form of geometrical scaling (motivated by the Balitski-Kovchegov (BK) equation with fixed coupling) studied in more detail in our previous paper, and four new hypotheses: phenomenologically motivated case with $Q^2$ dependent exponent $λ$ that governs small $x$ dependence of the saturation scale, two versions of scaling (running coupling 1 and 2) that follow from the BK equation with running coupling, and diffusive scaling suggested by the QCD evolution equation beyond mean field approximation. It turns out that more sophisticated scenarios: running coupling scaling and diffusive scaling are disfavored by the combined HERA data on $e^+p$ deep inelastic structure function $F_2$.

hep-ph↗

arXiv2013

Quantitative Study of Geometrical Scaling in Deep Inelastic Scattering at HERA

We propose a method to assess the quality of geometrical scaling in Deep Inelastic Scattering and apply it to the combined HERA data on $γ^{\ast}p$ cross-section. Using two different approaches based on Bjorken $x$ binning and binning in $γ^{\ast}p$ scattering energy $W$, we show that geometrical scaling in variable $τ\sim Q^{2} x^λ$ works well up to Bjorken $x$'s 0.1. The corresponding value of exponent $λ$ is 0.32 -- 0.34.

hep-ph↗

arXiv2012

Geometrical Scaling in High Energy Hadronic Collisions

After introducing the concept of geometrical scaling (GS) on the example of deep inelastic ep scattering, we show that GS is also present in the p_T spectra measured by the LHC. We discuss simple phenomenological signatures of GS and its applications.

hep-ph↗

arXiv2011

New look at geometrical scaling

In this note we discuss emergence of geometrical scaling (firstly proposed for deep inelastic collisions) in pp scattering at the LHC and in heavy ion collisions at RHIC. After discussing general properties of geometrical scaling (GS) we focus on simple signatures of GS, namely on ratios of the $p_{\rm T}$ values at which multiplicity spectra for different energies are equal.

hep-ph↗

arXiv2011

Negative Binomial Distribution and the multiplicity moments at the LHC

In this work we show that the latest LHC data on multiplicity moments $C_2-C_5$ are well described by a two-step model in the form of a convolution of the Poisson distribution with energy-dependent source function. For the source function we take $Γ$ Negative Binomial Distribution. No unexpected behavior of Negative Binomial Distribution parameter $k$ is found. We give also predictions for the higher energies of 10 and 14 TeV.

hep-ph↗

arXiv2011

Geometrical scaling in hadronic collisions

We show that the p_T spectra measured in pp collisions at the LHC exhibit geometrical scaling introduced earlier in the context of deep inelastic scattering. We also argue that the onset of geometrical scaling can be seen in nucleus-nucleus collisions at lower RHIC energies.

hep-ph↗

arXiv2011

Improved Geometrical Scaling at the LHC

We show that geometrical scaling exhibited by the $p_{\rm T}$ spectra measured by the CMS collaboration at the LHC is substantially improved if the exponent $λ$ of the saturation scale depends on $p_{\rm T}$. This dependence is shown to be the same as the dependence of small $x$ exponent of $F_2$ structure function in deep inelastic scattering taken at the scale $Q=p_{\rm T}/2$

hep-ph↗

arXiv2010

Saturation and Scaling of Multiplicity, Mean p_T and p_T Distributions from 200 GeV < sqrt{s} < 7 TeV - Addendum

In the previous paper we have argued that the LHC data on multiplicity, average transverse momentum, and charged particle transverse momentum distributions are well described with minimal modeling in terms of a saturation scale Q_sat(s). As a consequence, the p_T spectra should exhibit geometric scaling. In this short note we show that recently released CMS data at sqrt{s}=0.9, 2.36 and 7 TeV fall on a universal curve when plotted in terms of suitably defined scaling variable τ.

hep-ph↗

arXiv2010

Saturation and Scaling of Multiplicity, Mean p_T and p_T Distributions from 200 GeV < sqrt{s} < 7 TeV

The multiplicity, average transverse momentum, and charged particle transverse momentum distributions have recently been measured in LHC experiments. The multiplicity and average transverse momentum grow with beam energy. Such growth is expected in the theory of the Color Glass Condensate, a theory that incorporates the physics of saturation into the evolution of the gluon distribution. We show that the energy dependence of the $p\overline{p}$ data and the LHC data for $pp$ scattering at \sqrt{s} > 200 GeV may be simply described using a minimal amount of model input. Such a description uses parameters consistent with the Color Glass Condensate descriptions of HERA and RHIC experimental data.

hep-ph↗

arXiv2010

Importance of Mixing for Exotic Baryons

Exotic antidecuplet baryons are predicted to be not only surprisingly light but also very narrow. First we explain how small decay width arises in the quark soliton model. Next, we study possible mixing of exotic antidecuplet with Roper octet and discuss its phenomenological consequences.

hep-ph↗

arXiv2010

On strange SU(3) partners of Theta+

We propose a scenario in which Roper octet can mix with a putative antidecuplet of exotic baryons and predict the properties of its strange members. We show that 1795 MeV < M_Sigma_{\bar{10}} <1830 MeV and 1900 MeV < M_Xi_{\bar{10}}<1970 MeV. We also estimate total widths: 10 MeV < Gamma_Σ_{\bar{10}}< 30 MeV} and Gamma_Ξ_{\bar{10}}\sim 10 MeV and branching ratios for different decay modes.

hep-ph↗

arXiv2009

Photon Distribution Amplitudes in nonlocal chiral quark model

Photon distribution amplitudes up to twist four are calculated within the nonlocal chiral quark model with a simple pole ansatz for momentum dependence of the constituent quark mass. Calculations are performed using modified electromagnetic vector current in order to satisfy Ward identities. Quark condensate and magnetic susceptibility of the QCD vacuum entering definitions of the distribution amplitudes are computed and compared with existing phenomenological estimates. Both real and off-shell photons are considered and relevant form factors are calculated. Our results are analytical up to the numerical solution of certain algebraic equation.

hep-ph↗

arXiv2009

Pion-to-photon transition distribution amplitudes in the non-local chiral quark model

We apply the non-local chiral quark model to study vector and axial pion-to-photon transition amplitudes that are needed as a nonperturbative input to estimate the cross section of pion annihilation into the real and virtual photon. We use a simple form of the non-locality that allows to perform all calculations in the Minkowski space and guaranties polynomiality of the TDA's. We note only residual dependence on the precise form of the cut-off function, however vector TDA that is symmetric in skewedness parameter in the local quark model is no longer symmetric in the non-local case. We calculate also the transition form-factors and compare them with existing experimental parametrizations.

hep-ph↗

arXiv2007

On the exotic eikosiheptaplet

We use the chiral quark soliton model to estimate masses and widths of the two eikosiheptaplets (27-plets of SU(3) flavor) of spin 3/2 and 1/2 that emerge in the rigid rotator quantization. We use as input: hyperon decays, Theta+ mass and width. While 27_{3/2} has small widths (although much larger than the values allowed by the partial wave analysis), 27_{1/2} has large decay widths to antidecuplet. However exactly for this decay channels the widths are suppressed in the large N_{c} limit.

hep-ph↗

arXiv2007

Remarks on N_c dependence of decays of exotic baryons

We calculate the N_c dependence of the decay widths of exotic eikosiheptaplet within the framework of Chral Quark Soliton Model. We also discuss generalizations of regular baryon representations for arbitrary N_c.

hep-ph↗

arXiv2005

Chiral Soliton Model Predictions for Pentaquarks

We briefly describe chiral soliton model description of baryons and predictions for exotic antidecuplet. We discuss successful phenomenology which triggered experimental searches and problems which arise in the formal limit of large Nc.

hep-ph↗

arXiv2005

Exotic and nonexotic magnetic transitions in the context of the SELEX and GRAAL experiments

We calculate magnetic transition moments in the chiral quark-soliton model, with explicit SU(3)-symmetry breaking taken into account. The dynamical model parameters are fixed by experimental data for the magnetic moments of the baryon octet and from the recent measurements of $Θ^{+}$ mass. Known magnetic transition moments $μ_{ΛΣ}$, $μ_{NΔ}$ are reproduced and predictions for other octet-decuplet and octet-antidecuplet transitions are given. In particular $μ_{ΣΣ^{\ast}}$ recently constrained by SELEX is shown to be below $0.82 μ_N$. The recent GRAAL data on $η$ photoproduction off the nucleon are explained in terms of a new narrow antidecuplet neutron-like resonance.

hep-ph↗