Search

The 2D3V Aspherical Particle-in-Cell (APIC) code is developed for modeling of interactions of non-spherical dust grains with plasmas. It simulates the motion of plasma electrons and ions in a self-consistent electric field of plasma-screened charged dust particle. Due to absorption/recombination of plasma particles impinging on the grain surface, they transfer charge, momentum, angular momentum, as well as kinetic and binding energy, creating currents, forces, torques, and heat fluxes to the grain. The values of such physical parameters determine dust behavior in plasma, including its dynamics and ablation, and can be used in various plasma studies and applications, such as dusty plasmas, fusion devices, laboratory experiments, and astrophysical research. Obtaining these physical values for select non-spherical shapes of conducting dust grains is the main goal of the APIC code simulations.

It is shown that stationary non-spherical dust grain immersed into stationary non-magnetized plasma can experience a force caused by the grain-plasma interactions.

The contributions of the chiral gauge leptoquarks $V^{L,R}$ induced by the chiral four color quark-lepton symmetry to the branching ratios of $ K_L^0, B^0, B_s \to l_1 \, l_2 $ decays are calculated and analysed using the general parametrizations of the fermion mixing matrices in the leptoguark currents. From the current experimental data on these decays under assumption $ m_{V^L} \ll m_{V^R} $ the lower mass limit $ m_{V^L} \cos{\gamma_L} > 5.68 \,\, \mbox{TeV}$ is found, which in particular case of equal gauge coupling constants gives $ m_{V^L} > 8.03 \,\, \mbox{TeV} $. The branching ratios of the decays under consideration predicted by the chiral gauge leptoquarks are calculated and analysed in dependence on the leptoquark masses and the mixing parameters. It is shown that in consistency with the current experimental data these branching ratios for $ B_s, B^0 \to \mu e $ decays can be close to their experimental limits and those for $ B_s, B^0 \to \tau e, \tau \mu $ decays can be of order of~$10^{-7}$. The calculated branching ratios will be useful in the further experimental searches for these decays., Comment: 13 pages, 1 table, accepted for publication in Modern Physics Letters A

An impact of neutrals on anomalous edge plasma transport and zonal flow (ZF) is considered. As an example, it is assumed that edge plasma turbulence is driven by the resistive drift wave (RDW) instability. It is found that the actual effect of neutrals is not related to a suppression of the instability \textit{per se}, but due to an impact on the ZF. Particularly, it is shown that, whereas the neutrals make very little impact on the linear growth rate of the RDW instability, they can largely reduce the zonal flow generation in the nonlinear stage, which results in an enhancement of the overall anomalous plasma transport. Even though only RDW instability is considered, it seems that such an impact of neutrals on anomalous edge plasma transport has a very generic feature. It is conceivable that such neutral induced enhancement of anomalous plasma transport is observed experimentally in a detached divertor regime, which is accompanied by a strong increase of neutral density.

The contributions of the vector leptoquarks of Pati-Salam type to the branching ratios of $K_L^0, B^0, B_s \to l \, l^{\prime}$ decays are calculated with account of the fermion mixing in the leptoguark currents of the general type. Using the general parametrizations of the mixing matrices the lower vector leptoquark mass limit $ m_V > 86 \,\, TeV $ is found from the current experimental data on these decays. The branching ratios of the decays $B^0, B_s \to l \, l^{\prime}$ predicted at $m_V = 86 \,\, TeV$ are calculated. These branching ratios for the decays $ B^0, B_s \to \mu^+ \mu^-, e \mu $ are close to the experimental data whereas those for the decays $B^0 \to e^+ e^-, e \tau, \mu \tau$, and $B_s \to e^+ e^-$ are by order of $2\div4$ less than their current experimental limits. For the decays $B_s \to e \tau, \mu \tau$ these branching ratios are of order $10^{-10}$ and $10^{-9}$ respectively. The predicted branching ratios will be usefull in the current and future experimental searches for these decays., Comment: 10 pages, 1 table, minor corrections, final version for publication in Modern Physics Letters A

The scalar color octet contribution to the resonance $t\bar{t}$-pair production at the LHC is calculated and analysed with account of the one loop effective two gluon vertex. It is shown that this contribution from the scalar color octet $F_2$ predicted by the minimal model with the four color quark-lepton symmetry is for $\sqrt{s}=13$ TeV of about a few percents for $750 < m_{F_2} < 1800$ GeV and can exceed 10% for $400 < m_{F_2} < 750$ GeV. It is also pointed out that the search for the scalar octet $F_2$ as the resonance in the dijet mass spectra seems to be difficult because of the smallness of its one loop effective two gluon interaction., Comment: 12 pages, 5 figures, accepted for publication in Modern Physics Letters A

The contributions of $G'$-boson predicted by the chiral color symmetry of quarks to the differential dijet cross-sections in $pp$-collisions at the LHC are calculated and analysed in dependence on two free parameters of the model, the $G'$ mass $m_{G'}$ and mixing angle $\theta_G$. The exclusion and consistency $m_{G'}-\theta_G$ regions imposed by the ATLAS and CMS data on dijet cross-sections are found. Using the CT10 (MSTW~2008) PDF set we show that the $G'$-boson for $\theta_G=45^{\circ}$, i.e. the axigluon, with the masses $m_{G'} < 2.3 \,\, (2.6) \,\, \mbox{TeV}$ and $m_{G'} < 3.35 \,\, (3.25) \,\, \mbox{TeV}$ is excluded at the probability level of $95\%$ by the ATLAS and CMS dijet data respectively. For the other values of $\theta_G$ the exclusion limits are more stringent. The $m_{G'}-\theta_G$ regions consistent with these data at $CL=68\%$ and $CL=90\%$ are also found., Comment: 13 pages, 3 figures, accepted for publication in Modern Physics Letters A

The contributions of $G'$-boson predicted by the chiral color symmetry of quarks to the charge asymmetry $A_C(p p \to t\bar{t})$ in $t \bar{t}$ production at the LHC and to the forward-backward asymmetry $A_{\rm FB}(p\bar{p} \to t\bar{t})$ in $t\bar{t}$ production at the Tevatron are calculated and analysed in dependence on two free parameters of the model, the $G'$ mass $m_{G'}$ and mixing angle $\theta_G$. The $m_{G'} - \theta_G$ regions of $1 \sigma$ consistency with the CMS data on the cross section $\sigma(pp \to t\bar{t})$ and on the charge asymmetry $A_C(p p \to t\bar{t})$ are found and compared with those resulted from the CDF data on the cross section $\sigma(p\bar{p} \to t\bar{t})$ and on the forward-backward asymmetry $A_{\rm FB}(p\bar{p} \to t\bar{t})$ of $t \bar{t}$ production at the Tevatron with account of the current SM predictions for $A_{\rm FB}(p\bar{p} \to t\bar{t})$., Comment: 11 pages, 3 figures, accepted for publication in Modern Physics Letters A; v2: corrected misprint, added references

The contributions of scalar leptoquarks in lepton flavor violating (LFV) processes of type $l_i\to l_j \gamma$ are investigated in frame of the minimal model with the four color symmetry and Higgs mechanism of quark and lepton mass generation. It is shown that experimental data on the decays $\mu\to e \gamma$, $\tau \to \mu \gamma$, $\tau\to e \gamma$ allow the existence of light scalar leptoquarks of type under consideration, with masses of order 1 TeV or below., Comment: 7 pages, 4 figures. Submitted to Proceedings of the 16th International Seminar on High Energy Physics "QUARKS-2010", Kolomna, Russia, 6-12 June, 2010

The contributions to the cross section $\sigma_{t\bar{t}}$ and to the forward-backward asymmetry $A_{\rm FB}^{t \bar t}$ of $t\bar{t}$ production at the Tevatron from $Z'$-boson and scalar leptoquarks $S^{(\pm)}_a$ and scalar gluons $F_a$ predicted by the minimal model with four color quark-lepton symmetry are calculated. These contributions are shown to be small in tree approximation and can be significant with account of the 1-loop $gt\bar{t}$ effective vertex induced by the scalar doublets. The lower mass limit for scalar gluons $m_F \gtrsim 320\, GeV$ from the Tevatron data is obtained and it is shown that for $m_{F_1}\lesssim 990\,GeV$ the scalar gluon $F_1$ can be evident at LHC at the significance not less that $3\sigma$ (for $\sqrt{s}=14$ TeV, $L=10\,fb^{-1}$)., Comment: 11 pages, 5 figures. Submitted to Proceedings the 16th International Seminar on High Energy Physics "QUARKS-2010", Kolomna, Russia, 6-12 June, 2010

A gauge model with chiral color symmetry of quarks is considered and possible effects of the color $G'$-boson octet predicted by this symmetry are investigated. The contributions of the $G'$-boson to the cross section $\sigma_{t\bar{t}}$ and to the forward-backward asymmetry $A_{\rm FB}^{p \bar p}$ of $t\bar{t}$ production at the Tevatron are calculated and analysed in dependence on two free parameters of the model, the mixing angle $\theta_G$ and $G'$ mass $m_{G'}$. The $G'$-boson contributions to $\sigma_{t\bar{t}}$ and $A_{\rm FB}^{p \bar p}$ are shown to be consistent with the Tevatron data on $\sigma_{t\bar{t}}$ and $A_{\rm FB}^{p \bar p}$, the allowed region in the $m_{G'} - \theta_G$ plane is discussed and around $m_{G'}=1.2 \, TeV, \; \theta_G=14^\circ $ the region of $1 \sigma$ consistency is found., Comment: 7 pages, 1 figure. Submitted to Proceedings of the 16th International Seminar on High Energy Physics "QUARKS-2010", Kolomna, Russia, 6-12 June, 2010. Misprints in formula (8) are corrected. All the other results are valid

The contributions of $G'$-boson predicted by the chiral color symmetry of quarks to the cross section $\sigma_{t\bar{t}}$ and to the forward-backward asymmetry $A_{\rm FB}^{p \bar p}$ of $t\bar{t}$ production at the Tevatron are calculated with account of the difference of the strengths of the $\bar q q G$ and $\bar q q G'$ interactions. The results are analysed in dependence on two free parameters of the model, the mixing angle $\theta_G$ and $G'$ mass $m_{G'}$. The $G'$-boson contributions to $\sigma_{t\bar{t}}$ and $A_{\rm FB}^{p \bar p}$ are shown to be consistent with the Tevatron data on $\sigma_{t\bar{t}}$ and $A_{\rm FB}^{p \bar p}$, the allowed region in the $m_{G'} - \theta_G$ plane is discussed and around $m_{G'}=1.2 \, TeV, \; \theta_G=14^\circ $ the region of $1 \sigma$ consistency is found., Comment: 9 pages, 1 figure, misprints in formula (14) are corrected, all the other results are valid

A gauge model with chiral color symmetry is considered and possible effects of the color $G'$-boson octet predicted by this symmetry are investigated in dependence on two free parameters, the mixing angle $\theta_G$ and $G'$ mass $m_{G'}$. The allowed region in the $m_{G'} - \theta_G$ plane is found from the Tevatron data on the cross section $\sigma_{t\bar{t}}$ and forward-backward asymmetry $A_{\rm FB}^{p \bar p}$ of the $t\bar{t}$ production. The mass limits for the $G'$-boson are shown to be stronger than those for the axigluon. A possible effect of the $G'$-boson on the $t\bar{t}$ production at the LHC is discussed and the mass limits providing for the $G'$-boson evidence at the LHC are estimated in dependence on $\theta_G$., Comment: 11 pages, 2 figures, accepted for publication in Modern Physics Letters A

The cross section of the $\mu^+\mu^-$ pair production in $pp$-collisions at the LHC is calculated with acount of the $Z'$ boson induced by the minimal four color quark-lepton symmetry($MQLS$). The $\mu^+\mu^-$ invariant mass spectrum with account of the $MQLS$ $Z'$ boson is analysed in dependence on the $Z'$ mass. The mass region for the $MQLS$ $Z'$ boson observable at the LHC is found in dependence on the significance and on the integrated luminosity., Comment: 11 pages, 2 figures, accepted for publication in Modern Physics Letters A

Cross sections of the colored scalar particle production in $pp$-collisions are calculated and differential and total cross sections of the corresponding parton subprocesses are obtained. The total cross section of scalar gluon production in $pp$-collisions at the LHC is estimated and the dominant decays of scalar gluons are discussed. The production cross section of scalar gluons $F$ with masses $m_F\lesssim 1300$ GeV is shown to be sufficient for the effective production of these particles at the LHC., Comment: 10 pages, 3 figures, to be published in Mod. Phys. Lett. A

The contributions of scalar and gauge leptoquarks into widths of $K^0_L \to e^{\mp} \mu^{\pm}$, $B^0 \to e^{\mp} \tau^{\pm}$ decays are calculated in the models with the vectorlike and chiral four color symmetry and with the Higgs mechanism of the quark-lepton mass splitting. From the current data on $K^0_L$ and $B^0$ decays the mass limits for scalar and chiral leptoquarks and the updated vector leptoquark mass limits are obtained. It is shown that unlike the gauge leptoquarks the scalar leptoquark mass limits are weak, of order or below their direct mass limits. The search for such scalar leptoquarks at LHC and the further search for leptonic decays $ B^0 \to l^+_i l^-_j $ are of interest., Comment: 9 pages, 2 figures. To be published in Mod. Phys. Lett. A

The contributions of the scalar leptoquark doublets into widths of the $K^0_L \to e^{\mp} \mu^{\pm}$, $B^0 \to e^{\mp} \tau^{\pm}$ decays are calculated in MQLS model with Higgs mechanism of the quark-lepton mass splitting. The resulted mass limits for the scalar leptoquarks are investigated in comparision with those for vector and chiral gauge leptoquarks. It is shown that the scalar leptoquark mass limits are essentially weaker (about $200 GeV$) than those (a few hundreds $TeV$) for gauge leptoquarks. The search for such scalar leptoquark doublets at LHC and the search for the leptonic decays $ B^0 \to l^+_i l^-_j $ are of interest., Comment: 7 pages, 3 figures, submitted to Proceedings of the 14th International Seminar "Quarks'2006", Repino, St.Petersburg, Russia, May 19 - 25, 2006. Typos and mistake corrected, text and figures improved

Fermionic decays of the scalar leptoquarks $ S=S_1^{(+)}, S_1^{(-)}, S_m $ and of the scalar gluons $F=F_1, F_2$ predicted by the four color symmetry model with the Higgs mechanism of the quark-lepton mass splitting are investigated. Widths and branching ratios of these decays are calculated and analysed in dependence on coupling constants and on masses of the decaying particles. It is shown that the decays $ S_1^{(+)}\to tl^+_j, S_1^{(-)}\to \nu_i\tilde b, S_m\to t\tilde \nu_j, F_1\to t\tilde b, F_2\to t\tilde t $ are dominant with the widths of order of a few GeV for $m_S, m_F<1$ TeV and with the total branching ratios close to 1. In the case of $m_S < m_t$ the dominant scalar leptoquark decays are $ S_1^{(+)}\to cl_j^+, S_1^{(-)}\to \nu_i\tilde b, S_m\to b\l_j^+, S_m\to c\tilde \nu_j $ with the total branching ratios $Br(S_1^{(+)}\to cl^+) \approx $ $Br(S_1^{(-)}\to \nu\tilde b) \approx 1$, $Br(S_m\to bl^+) \approx 0.9$ and $Br(S_m\to c\tilde \nu) \approx 0.1.$ A search for such decays at the LHC and Tevatron may be of interest., Comment: 11 pages, 1 figure, 1 table, to be published in Modern Physics Letters A

The rare t-quark decays $t \to c l_j^{+} l_k^{-}$, $t \to c \tilde{\nu_j} \nu_k$ via the scalar leptoquark doublets are investigated in the minimal four color symmetry model with the Higgs mechanism of the quark-lepton mass splitting. The partial widths of these decays are calculated and the total width of the charged lepton mode $ \Gamma(t \to c {l^{+}}' l^{-})= \sum_{j,k} \Gamma(t \to c l_{j}^{+} l_{k}^{-})$ and the total width of the neutrino mode $ \Gamma(t \to c \tilde{\nu}' \nu)= \sum_{j,k} \Gamma(t \to c \tilde{\nu_{j}} \nu_{k})$ are found. The corresponding branching ratios are shown to be $ Br(t \to c {l^{+}}' l^{-}) \approx (3.5 - 0.4) 10^{-5}, $ $ Br(t \to c {\tilde{\nu}}' \nu) \approx (7.1 - 0.8) 10^{-5} $ for the scalar leptoquark masses $ m_{S}= 180 - 250 GeV $ and for the appropriate values $ (\sin{\beta} \approx 0.2) $ of the mixing angle of the model. The search for such decays at LHC may be of interest., Comment: 18 pages, 2 figures, 1 table, to be published in Modern Physics Letters A; corrected typos

The contributions into radiative correction parameters S, T, U from scalar leptoquark and scalar gluon doublets are investigated in the minimal four color symmetry model. It is shown that the existence of the relatively light scalar leptoquarks and scalar gluons (with masses of order of 1 TeV or less) is consistent with the current experimental data on S, T, U and the more light particles (with masses below 400 GeV) improve the fit. In particular, the lightest scalar leptoquarks with masses below 300 GeV are consistent with the current data on S, T, U at $\chi^2 < 3.1(3.2)$ for $m_H=115(300) GeV$ in comparison with $\chi^2 = 3.5(5.0)$ in the Standard Model. The lightest scalar gluon in this case is expected to lie below $ 850(720) GeV.$ The possible significance of such particles in the t-quark physics at LHC is emphasized and their effect on the gauge coupling constant unification is briefly discussed., Comment: 10 pages, 2 figures, submitted to Proceedings of the 12 th International Seminar on High Energy Physics "Quarks-2002", Novgorod the Great, Russia, June 1-7, 2002

The contributions into radiative correction parameters S, T, U from scalar leptoquark and scalar gluon doublets are investigated in the minimal four color symmetry model. It is shown that the current experimental data on S, T, U allow the scalar leptoquarks and the scalar gluons to be relatively light (with masses of order of 1 TeV or less), the lightest particles are preferred to lie below 400 GeV. In particular, the lightest scalar leptoquarks with masses below 300 GeV are shown to be compatible with the current data on S, T, U at $\chi^2 < 3.1 (3.2)$ for $m_H = 115 (300) GeV$ in comparison with $\chi^2 = 3.5 (5.0)$ in the Standard Model. The lightest scalar gluon in this case is expected to lie below 850 (720) GeV. The possible significance of such particles in the t-quark physics at LHC is emphasized., Comment: 14 pages, 2 figures, to appear in Physics Letters B

Quark-gluon decays of heavy paraquarkonia $^1 S_0(\bar Q Q) \to \bar q q g$ are investigated with account of the masses of final quarks. The decay widths and the energy distributions of the final quarks and gluons are calculated in dependence on the relative quark masses. The strong collinear enhancement of the gluon energy distribution at the end of the spectrum is shown to take place in all such decays of $\eta_c$ and $\eta_b$ mesons except the decay $\eta_b \to \bar c c g$. The total decay width is shown to have an essential dependence on the final quark masses. The corresponding branching ratios of $\eta_c$ and $\eta_b$ mesons are numerically estimated with a good agreement of $Br(\eta_c \to \bar s s g)$ with experimental data on $\eta_c$ decays., Comment: 12 pages, 4 ps figures, LaTeX, uses epsf.sty, corrected some typos

The contributions into radiative correction parameters S, T, U from the scalar leptoquarks are calculated in the minimal gauge model with the four-color quark-lepton symmetry. It is shown that the contributions into T and U from the scalar leptoquark doublets are not positive definite. Using the current experimental data on S, T, U the bounds on the scalar leptoquark masses are obtained. In particular, the existence of the relatively light scalar leptoquark with electric charge 2/3 is shown to be compatible with the current experimental data on S, T, U., Comment: 14 pages, 3 ps figures, LaTeX, uses epsf.sty, accepted for publication in Physics Letters B

A minimal extension of the Standard Model containing the four-color quark-lepton symmetry is proposed and discussed. The existence of a rather light extra $Z'$-boson originated from the four-color quark-lepton symmetry is shown to be compatible with the current electroweak data. The cross sections $\sigma(e^+ e^- \rightarrow \gamma, Z, Z' \rightarrow \bar f f)$ are calculated, and their deviations from the SM predictions are shown to be significant at $\sqrt s \ge 200 GeV$ and available for the measurements at the LEP200 and future colliders., Comment: 15 pages, LaTeX, 1 figure available on request; to be published in Phys. Lett. B

The decay of heavy orthoquarkonium into quark-antiquark pair and two gluons is considered. The differential probability of the decay in the tree approximation is calculated and the final quark mass influence on the quark and gluon distribution functions is studied. It is shown that the collinear strengthening of the bottomonium decay probability takes place at the $u \bar u$-, $d \bar d$- and $s \bar s$- pair production and is absent at the $c \bar c$- production., Comment: (talk given at the VIII International Seminar "Quarks-94", Vladimir, Russia, May 11-18, 1994), 6 pages, LaTeX (uses world_sci.sty), (three figures may be received by request), Yaroslavl, Yaroslavl State University preprint YARU-HE-94/07

A minimal extension of the Standard Model containing the four-color quark-lepton symmetry is discussed. Some features of an additional $Z'$-boson originated from this symmetry are investigated and the limits on $m_{Z'}$ from the current TRISTAN data and the possible limits on $m_{Z'}$ from the future LEP200 collider are obtained., Comment: (talk given at the VIII International Seminar "Quarks-94", Vladimir, Russia, May 11-18, 1994), 9 pages, LaTeX (uses world_sci.sty), (three figures may be received by request), Yaroslavl, Yaroslavl State University preprint YARU-HE-94/06