Proceedings of XXI International Workshop on Deep-Inelastic Scattering and Related Subjects — PoS(DIS 2013)
We discuss production of two pairs of cc in proton-proton collisions at the LHC. Both doubleparto... more We discuss production of two pairs of cc in proton-proton collisions at the LHC. Both doubleparton scattering (DPS) and single-parton scattering (SPS) contributions are included in the analysis. Each step of DPS is calculated within k t-factorization approach. The conditions how to identify the DPS contribution are presented. The discussed mechanism leads to the production of pairs of mesons: each containing c quarks or each containingc antiquarks. We discuss corresponding production rates and some differential distributions for (D 0 D 0 +D 0D0) production. Within large theoretical uncertainties the predicted DPS cross section is fairly similar to the cross section measured recently by the LHCb collaboration. The best description is obtained with the Kimber-Martin-Ryskin (KMR) unintegrated gluon distribution. The contribution of SPS, calculated in the high-energy approximation, turned out to be rather small. Finally, we emphasize significant contribution of DPS mechanism to inclusive charmed meson spectra measured recently by ALICE, ATLAS and LHCb.
In the following we stress the advantages of the NICA research programme in the context of studyi... more In the following we stress the advantages of the NICA research programme in the context of studying the spectator-induced electromagnetic phenomena present in heavy-ion collisions. We point at the specific interest of using these phenomena as a new, independent source of information on the spacetime evolution of the reaction and of the non-perturbative process of particle production. We propose an extended series of measurements of well-defined observables to be performed in different types of nuclear reactions and in the whole range of collision energies available to NICA. We expect these measurements to bring very valuable new insight into the mechanism of non-perturbative strong interactions, complementary to the studies made at the SPS at CERN, RHIC at BNL, and the LHC.
Proceedings of XXI International Workshop on Deep-Inelastic Scattering and Related Subjects — PoS(DIS 2013)
We discuss production of charmed mesons as well as electrons/muons from semileptonic decays of ch... more We discuss production of charmed mesons as well as electrons/muons from semileptonic decays of charm and bottom mesons in proton-proton collisions at the LHC. The cross section for inclusive production of cc and bb pairs is calculated in the framework of the k ⊥-factorization approach. Here, the KMR and Jung CCFM unintegrated gluon distribution functions are used. Theoretical uncertainties of the model related to the choice of renormalization and factorization scales as well as due to the quark mass are also discussed. The hadronization of charm and bottom quarks is included within the fragmentation functions technique. Inclusive differential distributions in transverse momentum of charmed mesons are presented and compared to recent results of the ALICE collaboration. Furthermore, we also consider production of different DD pairs in unique kinematics of forward rapidities of the LHCb experiment. Kinematical correlations in azimuthal angle ϕ DD and invariant mass M DD distributions are presented and compared to LHCb data. Furthermore, the semileptonic decays of charm and bottom mesons are done with the help of decay functions found by fitting recent semileptonic data obtained by the CLEO and BABAR collaborations. Inclusive differential distributions in transverse momentum of leptons for several kinematical regions are presented and compared to recent results of the ALICE and CMS collaborations.
We discuss how the dijet azimuthal correlations in DIS and real photoproduction at HERA probe the... more We discuss how the dijet azimuthal correlations in DIS and real photoproduction at HERA probe the differential (unintegrated) gluon distribution in the proton. We find a strong dependence of the azimuthal correlation pattern on Bjorken-x, photon virtuality and the cut on the jet transverse momenta. A rise of the azimuthal decorrelations is observed with decreasing Bjorken-x due to the interplay of perturbative and nonperturbative effects. We predict a strong rise of the same-side jet rate with photon energy for real photoproduction. We discuss conditions for the correlation function to be dominated by hard perturbative gluons and ways of constraining the size of the nonperturbative soft component. We make some predictions for the THERA energy range. The analysis of the energy dependence of the isolated jet and two-jet cross sections in photoproduction would be a new way to study the not yet well constrained unintegrated gluon distributions and to explore the onset of the pQCD regime.
Zeitschrift f�r Physik C Particles and Fields, 1997
Recently the concept of the pion cloud in the nucleon turned out to be successful in understandin... more Recently the concept of the pion cloud in the nucleon turned out to be successful in understanding the Gottfried sum rule violation observed by the New Muon Collaboration and the Drell-Yan asymmetry measured in NA51 at CERN. We propose a further possibility to test this concept at HERA through the analysis of the structure of deep inelastic scattering (DIS) events induced by pion-exchange. Momentum and energy distributions of outgoing nucleons as well as rapidity and multiplicity distributions are investigated using Monte Carlo simulations. Most observables cannot distinguish this process from ordinary DIS, but in the energy distribution of final neutrons we find a significantly different prediction from the pion cloud model. Forward neutron calorimeters will be essential to test the concept of pions in the nucleon.
A few applications of recent unintegrated parton distributions from the solution of the recent eq... more A few applications of recent unintegrated parton distributions from the solution of the recent equations formulated by Jan Kwieciński are shown.
We discuss results of the k t-factorization approach for heavy quark-heavy antiquark correlations... more We discuss results of the k t-factorization approach for heavy quark-heavy antiquark correlations in proton-proton and proton-antiproton collisions for RHIC, Tevatron and LHC. We consider correlations in the azimuthal angle as well as in the two-dimensional space of transverse momentum of heavy quark and heavy antiquark. We compare results obtained with the help of different unintegrated parton distributions (UPDF) from the literature.
We report on a detailed investigation of exclusive J/ψ production in proton-proton and proton-ant... more We report on a detailed investigation of exclusive J/ψ production in proton-proton and proton-antiproton collisions. Predictions for Tevatron and LHC energies are included.
We discuss production of charm quarks and mesons as well as nonphotonic electrons in pp scatterin... more We discuss production of charm quarks and mesons as well as nonphotonic electrons in pp scattering at RHIC. The distributions in rapidity and transverse momentum of charm and bottom quarks/antiquarks are calculated in the k t-factorization approach. The hadronization of heavy quarks is done by means of fenomenological fragmentation functions. The semileptonic decay functions found by fitting semileptonic decay data measured by the CLEO and BABAR collaborations are used. Good description of the inclusive data at large transverse momenta of electrons is obtained and a missing strength at small transverse momenta of electrons is found. Furthermore we discuss kinematical correlations between charged leptons from semileptonic decays of open charm/bottom, leptons produced in the Drell-Yan mechanism as well as some other mechanisms not included so far in the literature. When calculating the Drell-Yan processes we include transverse momenta of q andq, using the Kwieciński parton distributions. Reactions initiated by purely QED γ * γ *-fusion in elastic and inelastic pp collisions as well as diffractive mechanism of exclusive cc production are included. A good description of the dilepton invariant mass spectrum measured by the PHENIX collaboration is achieved. Predictions for the dilepton pair transverse momentum distribution as well as distribution in azimuthal angle between electron and positron are presented.
We discuss exclusive central diffractive production of scalar ($f_{0}(980)$, $f_{0}(1370)$, $f_{0... more We discuss exclusive central diffractive production of scalar ($f_{0}(980)$, $f_{0}(1370)$, $f_{0}(1500)$), pseudoscalar ($\eta$, $\eta'(958)$), and vector ($\rho^{0}$) mesons in proton-proton collisions. The amplitudes are formulated in terms of effective vertices required to respect standard rules of Quantum Field Theory and propagators for the exchanged pomeron and reggeons. Different pomeron-pomeron-meson tensorial (vectorial) coupling structures are possible in general. In most cases two lowest orbital angular momentum - spin couplings are necessary to describe experimental differential distributions. For the $f_{0}(980)$ and $\eta$ production the reggeon-pomeron, pomeron-reggeon, and reggeon-reggeon exchanges are included in addition, which seems to be necessary at relatively low energies. The theoretical results are compared with the WA102 experimental data, in order to determine the model parameters. For the $\rho^{0}$ production the photon-pomeron and pomeron-photon exc...
Acta Physica Polonica B Proceedings Supplement, 2015
A few examples of quickly developing field of double parton scattering are discussed. We present ... more A few examples of quickly developing field of double parton scattering are discussed. We present arguments that the production of two pairs of charm quark-antiquark is the golden reaction to study the double parton scattering effects. We discuss briefly also mechanism of single parton scattering and show that it gives much smaller contribution to the cccc final state. In this context we discuss also the contribution of perturbative parton-splitting mechanism which should also be added to the conventional DPS mechanism. The presence of the letter leads to collision energy and other kinematical variables dependence of so-called σ ef f. We briefly discuss production of four jets. We concentrate on estimation of the contribution of DPS for jets widely separated in rapidity. Finally we briefly mention about DPS effects in production of W + W − .
The cross sections for the production of two-pions in ultraperipheral ultrarelativistic heavy ion... more The cross sections for the production of two-pions in ultraperipheral ultrarelativistic heavy ion collisions, calculated in the impact parameter Equivalent Photon Approximation (EPA), are presented. Differential distributions in impact parameter, dipion invariant mass, single pion and dipion rapidity, pion transverse momentum and pion pseudorapidity are shown. The γγ → π + π − subprocess constitutes a background to the AA → Aρ 0 (→ π + π −)A process, initiated by emission of a photon by one of colliding nuclei. Only a part of the dipion invariant mass distribution associated with the γγ-collisions can be visible as the cross section for the AA → Aρ 0 A reaction is very large. Differential distributions for two ρ 0 meson production in exclusive ultraperipheral, ultrarelativistic collisions via a double scattering mechanism are presented. The cross section for γA → ρ 0 A is parametrized based on a calculation from the literature. Smearing of ρ 0 masses is taken into account. The results of calculations are compared to experimental data obtained at RHIC and to the contribution of the two-photon mechanism. The double scattering mechanism populates larger ρ 0 ρ 0 invariant masses and larger rapidity distances between the two ρ 0 mesons compared to the γγ fusion. It gives a significant contribution to the AA → AAπ + π − π + π − reaction. Some observables related to charged pions are presented. The results of our calculation are compared with the STAR collaboration results for four charged pion production. While the shape in invariant mass of the four-pion system is very similar to the measured one, the predicted cross section constitutes only 20 % of the measured one.
The γγ → ππ reactions are discussed. To describe those processes, we include dipion continuum, re... more The γγ → ππ reactions are discussed. To describe those processes, we include dipion continuum, resonances, high-energy pion-pion rescatterings, ρ meson exchange and pQCD Brodsky-Lepage mechanisms. The cross section for the production of pion pairs in photon-photon collisions in peripheral heavy ion collisions is calculated with the help of Equivalent Photon Approximaption (EPA) in the impact parameter space. We show predictions at √sNN TeV which could be measured e.g. by the ALICE collaboration at the LHC.
ABSTRACT The angular distributions of elastic and inelastic scattering of the 12C ions on the 9Be... more ABSTRACT The angular distributions of elastic and inelastic scattering of the 12C ions on the 9Be nuclei were measured using the Kiev U-240 cyclotron at the beam energy 65 MeV for the transitions to the ground state of the 12C nucleus and to the ground, 1.68 MeV and 2.43 MeV excited states of the 9Be nucleus. These data and elastic scattering in the 9Be + 12C system in the energy range of Ecm=5.14–90.46 MeV were analyzed within the optical and coupled reaction channel (CRC) models. The elastic and inelastic scattering, transfer reactions and spin reorientation of the 9Be nucleus in the ground state were included in the coupled channel scheme. The data of inelastic scattering at Elab(12C)=65 MeV were used to determine the deformation parameters of 9Be nucleus in the ground state. It was found that the reorientation process dominates in the elastic scattering data at large angles. A good description of all sets of experimental data was achieved. The energy dependence of parameters for the real and imaginary parts of the optical potential was analyzed using analytic forms of the Woods–Saxon type. The dispersion relation between the real and imaginary parts of the optical potential was applied in the analysis of the energy dependence. The parameters for the energy dependence of the 9Be + 12C optical potential were determined.
ABSTRACT Angular distributions of the 6Li(18O, 17O)7Li reaction were measured at Elab(O18)=114 Me... more ABSTRACT Angular distributions of the 6Li(18O, 17O)7Li reaction were measured at Elab(O18)=114 MeV for ground and excited states of the exit channel nuclei for the first time. The data were analyzed within the coupled-reaction-channels method (CRC). The 6Li + 18O elastic and inelastic scattering channels as well as simplest one- and two-step reactions were included in the coupled-reaction-channels scheme. The 7Li + 17O potential was deduced by fitting CRC calculations to the reaction data. The spectroscopic amplitudes for single nucleon and nuclear cluster configurations were calculated within the translationally invariant shell model. Isotopic differences of the 7Li + 16, 17, 18O and 7, 8Li + 17O potentials and the reaction mechanisms were studied.
The angular distributions of elastic and inelastic scattering of the ~4N ions on the ~2C nuclei a... more The angular distributions of elastic and inelastic scattering of the ~4N ions on the ~2C nuclei at the energy E(~4N) = 116 MeV for the transitions to the 4.44 MeV (2 +) excited state of ~2C and to the 3.95 MeV (1+), 4.915 MeV (0-) +5.11 MeV (2-) excited states of 14N as well as the 12C(14N, 13C)13N, 12C(14N, 13N)I3C and 12C(14N, 12C)14N transfer reactions were measured. The experimental data were analyzed using the coupled reaction channels (CRC) model. All measured quasi-elastic channels were included in the coupling scheme of the CRC calculation. The strong coupled-channel effects were observed. The optical model potentials for the ~2C+~4N and ~3C + 13N channels were deduced. The deformation parameters for the ~2C and ~4N nuclei were obtained from the CRC analysis of inelastic scattering. The isotopic effects in the 14N ion scattering off the J2C and ~4C targets were investigated. Both one-and two-step processes were studied for transfer channels. It was found that two-step transfers give significant contributions to some reaction channels. Good description of all experimental data was achieved. (~) 1997 Elsevier Science B.V.
A generalization of the usual PWIA in the application to quasi-free reaction processes has been p... more A generalization of the usual PWIA in the application to quasi-free reaction processes has been presented. The existence of quasi-free effects was tested in the 9Be(d, ta)4He reaction at 7 MeV. Evidence for quasi-free effects has been found by comparison of discrepancies between the experimental data and the R-matrix theory of resonant states, with predictions of the model presented. PACS 24.50-Direct reactions and scattering. PACS 25.10-Nuclear reactions and scattering involving few-nucleon systems.
The "triple-Regge" analysis of subleading Reggeon contributions to the diffractive structure func... more The "triple-Regge" analysis of subleading Reggeon contributions to the diffractive structure function in DIS at HERA is presented. The recently published data allow to determine the only free parameter of the analysis related to the ratio of the RRIP and IP IP IP couplings. The large value of this ratio is prefered which is in agreement with analyses of soft hadronic interactions. The role of the subleading Reggeons as well as pions for the fast forward neutron production in diffractive processes is estimated. The forward πN state production is also discussed.
Proceedings of XXI International Workshop on Deep-Inelastic Scattering and Related Subjects — PoS(DIS 2013)
We discuss production of two pairs of cc in proton-proton collisions at the LHC. Both doubleparto... more We discuss production of two pairs of cc in proton-proton collisions at the LHC. Both doubleparton scattering (DPS) and single-parton scattering (SPS) contributions are included in the analysis. Each step of DPS is calculated within k t-factorization approach. The conditions how to identify the DPS contribution are presented. The discussed mechanism leads to the production of pairs of mesons: each containing c quarks or each containingc antiquarks. We discuss corresponding production rates and some differential distributions for (D 0 D 0 +D 0D0) production. Within large theoretical uncertainties the predicted DPS cross section is fairly similar to the cross section measured recently by the LHCb collaboration. The best description is obtained with the Kimber-Martin-Ryskin (KMR) unintegrated gluon distribution. The contribution of SPS, calculated in the high-energy approximation, turned out to be rather small. Finally, we emphasize significant contribution of DPS mechanism to inclusive charmed meson spectra measured recently by ALICE, ATLAS and LHCb.
In the following we stress the advantages of the NICA research programme in the context of studyi... more In the following we stress the advantages of the NICA research programme in the context of studying the spectator-induced electromagnetic phenomena present in heavy-ion collisions. We point at the specific interest of using these phenomena as a new, independent source of information on the spacetime evolution of the reaction and of the non-perturbative process of particle production. We propose an extended series of measurements of well-defined observables to be performed in different types of nuclear reactions and in the whole range of collision energies available to NICA. We expect these measurements to bring very valuable new insight into the mechanism of non-perturbative strong interactions, complementary to the studies made at the SPS at CERN, RHIC at BNL, and the LHC.
Proceedings of XXI International Workshop on Deep-Inelastic Scattering and Related Subjects — PoS(DIS 2013)
We discuss production of charmed mesons as well as electrons/muons from semileptonic decays of ch... more We discuss production of charmed mesons as well as electrons/muons from semileptonic decays of charm and bottom mesons in proton-proton collisions at the LHC. The cross section for inclusive production of cc and bb pairs is calculated in the framework of the k ⊥-factorization approach. Here, the KMR and Jung CCFM unintegrated gluon distribution functions are used. Theoretical uncertainties of the model related to the choice of renormalization and factorization scales as well as due to the quark mass are also discussed. The hadronization of charm and bottom quarks is included within the fragmentation functions technique. Inclusive differential distributions in transverse momentum of charmed mesons are presented and compared to recent results of the ALICE collaboration. Furthermore, we also consider production of different DD pairs in unique kinematics of forward rapidities of the LHCb experiment. Kinematical correlations in azimuthal angle ϕ DD and invariant mass M DD distributions are presented and compared to LHCb data. Furthermore, the semileptonic decays of charm and bottom mesons are done with the help of decay functions found by fitting recent semileptonic data obtained by the CLEO and BABAR collaborations. Inclusive differential distributions in transverse momentum of leptons for several kinematical regions are presented and compared to recent results of the ALICE and CMS collaborations.
We discuss how the dijet azimuthal correlations in DIS and real photoproduction at HERA probe the... more We discuss how the dijet azimuthal correlations in DIS and real photoproduction at HERA probe the differential (unintegrated) gluon distribution in the proton. We find a strong dependence of the azimuthal correlation pattern on Bjorken-x, photon virtuality and the cut on the jet transverse momenta. A rise of the azimuthal decorrelations is observed with decreasing Bjorken-x due to the interplay of perturbative and nonperturbative effects. We predict a strong rise of the same-side jet rate with photon energy for real photoproduction. We discuss conditions for the correlation function to be dominated by hard perturbative gluons and ways of constraining the size of the nonperturbative soft component. We make some predictions for the THERA energy range. The analysis of the energy dependence of the isolated jet and two-jet cross sections in photoproduction would be a new way to study the not yet well constrained unintegrated gluon distributions and to explore the onset of the pQCD regime.
Zeitschrift f�r Physik C Particles and Fields, 1997
Recently the concept of the pion cloud in the nucleon turned out to be successful in understandin... more Recently the concept of the pion cloud in the nucleon turned out to be successful in understanding the Gottfried sum rule violation observed by the New Muon Collaboration and the Drell-Yan asymmetry measured in NA51 at CERN. We propose a further possibility to test this concept at HERA through the analysis of the structure of deep inelastic scattering (DIS) events induced by pion-exchange. Momentum and energy distributions of outgoing nucleons as well as rapidity and multiplicity distributions are investigated using Monte Carlo simulations. Most observables cannot distinguish this process from ordinary DIS, but in the energy distribution of final neutrons we find a significantly different prediction from the pion cloud model. Forward neutron calorimeters will be essential to test the concept of pions in the nucleon.
A few applications of recent unintegrated parton distributions from the solution of the recent eq... more A few applications of recent unintegrated parton distributions from the solution of the recent equations formulated by Jan Kwieciński are shown.
We discuss results of the k t-factorization approach for heavy quark-heavy antiquark correlations... more We discuss results of the k t-factorization approach for heavy quark-heavy antiquark correlations in proton-proton and proton-antiproton collisions for RHIC, Tevatron and LHC. We consider correlations in the azimuthal angle as well as in the two-dimensional space of transverse momentum of heavy quark and heavy antiquark. We compare results obtained with the help of different unintegrated parton distributions (UPDF) from the literature.
We report on a detailed investigation of exclusive J/ψ production in proton-proton and proton-ant... more We report on a detailed investigation of exclusive J/ψ production in proton-proton and proton-antiproton collisions. Predictions for Tevatron and LHC energies are included.
We discuss production of charm quarks and mesons as well as nonphotonic electrons in pp scatterin... more We discuss production of charm quarks and mesons as well as nonphotonic electrons in pp scattering at RHIC. The distributions in rapidity and transverse momentum of charm and bottom quarks/antiquarks are calculated in the k t-factorization approach. The hadronization of heavy quarks is done by means of fenomenological fragmentation functions. The semileptonic decay functions found by fitting semileptonic decay data measured by the CLEO and BABAR collaborations are used. Good description of the inclusive data at large transverse momenta of electrons is obtained and a missing strength at small transverse momenta of electrons is found. Furthermore we discuss kinematical correlations between charged leptons from semileptonic decays of open charm/bottom, leptons produced in the Drell-Yan mechanism as well as some other mechanisms not included so far in the literature. When calculating the Drell-Yan processes we include transverse momenta of q andq, using the Kwieciński parton distributions. Reactions initiated by purely QED γ * γ *-fusion in elastic and inelastic pp collisions as well as diffractive mechanism of exclusive cc production are included. A good description of the dilepton invariant mass spectrum measured by the PHENIX collaboration is achieved. Predictions for the dilepton pair transverse momentum distribution as well as distribution in azimuthal angle between electron and positron are presented.
We discuss exclusive central diffractive production of scalar ($f_{0}(980)$, $f_{0}(1370)$, $f_{0... more We discuss exclusive central diffractive production of scalar ($f_{0}(980)$, $f_{0}(1370)$, $f_{0}(1500)$), pseudoscalar ($\eta$, $\eta'(958)$), and vector ($\rho^{0}$) mesons in proton-proton collisions. The amplitudes are formulated in terms of effective vertices required to respect standard rules of Quantum Field Theory and propagators for the exchanged pomeron and reggeons. Different pomeron-pomeron-meson tensorial (vectorial) coupling structures are possible in general. In most cases two lowest orbital angular momentum - spin couplings are necessary to describe experimental differential distributions. For the $f_{0}(980)$ and $\eta$ production the reggeon-pomeron, pomeron-reggeon, and reggeon-reggeon exchanges are included in addition, which seems to be necessary at relatively low energies. The theoretical results are compared with the WA102 experimental data, in order to determine the model parameters. For the $\rho^{0}$ production the photon-pomeron and pomeron-photon exc...
Acta Physica Polonica B Proceedings Supplement, 2015
A few examples of quickly developing field of double parton scattering are discussed. We present ... more A few examples of quickly developing field of double parton scattering are discussed. We present arguments that the production of two pairs of charm quark-antiquark is the golden reaction to study the double parton scattering effects. We discuss briefly also mechanism of single parton scattering and show that it gives much smaller contribution to the cccc final state. In this context we discuss also the contribution of perturbative parton-splitting mechanism which should also be added to the conventional DPS mechanism. The presence of the letter leads to collision energy and other kinematical variables dependence of so-called σ ef f. We briefly discuss production of four jets. We concentrate on estimation of the contribution of DPS for jets widely separated in rapidity. Finally we briefly mention about DPS effects in production of W + W − .
The cross sections for the production of two-pions in ultraperipheral ultrarelativistic heavy ion... more The cross sections for the production of two-pions in ultraperipheral ultrarelativistic heavy ion collisions, calculated in the impact parameter Equivalent Photon Approximation (EPA), are presented. Differential distributions in impact parameter, dipion invariant mass, single pion and dipion rapidity, pion transverse momentum and pion pseudorapidity are shown. The γγ → π + π − subprocess constitutes a background to the AA → Aρ 0 (→ π + π −)A process, initiated by emission of a photon by one of colliding nuclei. Only a part of the dipion invariant mass distribution associated with the γγ-collisions can be visible as the cross section for the AA → Aρ 0 A reaction is very large. Differential distributions for two ρ 0 meson production in exclusive ultraperipheral, ultrarelativistic collisions via a double scattering mechanism are presented. The cross section for γA → ρ 0 A is parametrized based on a calculation from the literature. Smearing of ρ 0 masses is taken into account. The results of calculations are compared to experimental data obtained at RHIC and to the contribution of the two-photon mechanism. The double scattering mechanism populates larger ρ 0 ρ 0 invariant masses and larger rapidity distances between the two ρ 0 mesons compared to the γγ fusion. It gives a significant contribution to the AA → AAπ + π − π + π − reaction. Some observables related to charged pions are presented. The results of our calculation are compared with the STAR collaboration results for four charged pion production. While the shape in invariant mass of the four-pion system is very similar to the measured one, the predicted cross section constitutes only 20 % of the measured one.
The γγ → ππ reactions are discussed. To describe those processes, we include dipion continuum, re... more The γγ → ππ reactions are discussed. To describe those processes, we include dipion continuum, resonances, high-energy pion-pion rescatterings, ρ meson exchange and pQCD Brodsky-Lepage mechanisms. The cross section for the production of pion pairs in photon-photon collisions in peripheral heavy ion collisions is calculated with the help of Equivalent Photon Approximaption (EPA) in the impact parameter space. We show predictions at √sNN TeV which could be measured e.g. by the ALICE collaboration at the LHC.
ABSTRACT The angular distributions of elastic and inelastic scattering of the 12C ions on the 9Be... more ABSTRACT The angular distributions of elastic and inelastic scattering of the 12C ions on the 9Be nuclei were measured using the Kiev U-240 cyclotron at the beam energy 65 MeV for the transitions to the ground state of the 12C nucleus and to the ground, 1.68 MeV and 2.43 MeV excited states of the 9Be nucleus. These data and elastic scattering in the 9Be + 12C system in the energy range of Ecm=5.14–90.46 MeV were analyzed within the optical and coupled reaction channel (CRC) models. The elastic and inelastic scattering, transfer reactions and spin reorientation of the 9Be nucleus in the ground state were included in the coupled channel scheme. The data of inelastic scattering at Elab(12C)=65 MeV were used to determine the deformation parameters of 9Be nucleus in the ground state. It was found that the reorientation process dominates in the elastic scattering data at large angles. A good description of all sets of experimental data was achieved. The energy dependence of parameters for the real and imaginary parts of the optical potential was analyzed using analytic forms of the Woods–Saxon type. The dispersion relation between the real and imaginary parts of the optical potential was applied in the analysis of the energy dependence. The parameters for the energy dependence of the 9Be + 12C optical potential were determined.
ABSTRACT Angular distributions of the 6Li(18O, 17O)7Li reaction were measured at Elab(O18)=114 Me... more ABSTRACT Angular distributions of the 6Li(18O, 17O)7Li reaction were measured at Elab(O18)=114 MeV for ground and excited states of the exit channel nuclei for the first time. The data were analyzed within the coupled-reaction-channels method (CRC). The 6Li + 18O elastic and inelastic scattering channels as well as simplest one- and two-step reactions were included in the coupled-reaction-channels scheme. The 7Li + 17O potential was deduced by fitting CRC calculations to the reaction data. The spectroscopic amplitudes for single nucleon and nuclear cluster configurations were calculated within the translationally invariant shell model. Isotopic differences of the 7Li + 16, 17, 18O and 7, 8Li + 17O potentials and the reaction mechanisms were studied.
The angular distributions of elastic and inelastic scattering of the ~4N ions on the ~2C nuclei a... more The angular distributions of elastic and inelastic scattering of the ~4N ions on the ~2C nuclei at the energy E(~4N) = 116 MeV for the transitions to the 4.44 MeV (2 +) excited state of ~2C and to the 3.95 MeV (1+), 4.915 MeV (0-) +5.11 MeV (2-) excited states of 14N as well as the 12C(14N, 13C)13N, 12C(14N, 13N)I3C and 12C(14N, 12C)14N transfer reactions were measured. The experimental data were analyzed using the coupled reaction channels (CRC) model. All measured quasi-elastic channels were included in the coupling scheme of the CRC calculation. The strong coupled-channel effects were observed. The optical model potentials for the ~2C+~4N and ~3C + 13N channels were deduced. The deformation parameters for the ~2C and ~4N nuclei were obtained from the CRC analysis of inelastic scattering. The isotopic effects in the 14N ion scattering off the J2C and ~4C targets were investigated. Both one-and two-step processes were studied for transfer channels. It was found that two-step transfers give significant contributions to some reaction channels. Good description of all experimental data was achieved. (~) 1997 Elsevier Science B.V.
A generalization of the usual PWIA in the application to quasi-free reaction processes has been p... more A generalization of the usual PWIA in the application to quasi-free reaction processes has been presented. The existence of quasi-free effects was tested in the 9Be(d, ta)4He reaction at 7 MeV. Evidence for quasi-free effects has been found by comparison of discrepancies between the experimental data and the R-matrix theory of resonant states, with predictions of the model presented. PACS 24.50-Direct reactions and scattering. PACS 25.10-Nuclear reactions and scattering involving few-nucleon systems.
The "triple-Regge" analysis of subleading Reggeon contributions to the diffractive structure func... more The "triple-Regge" analysis of subleading Reggeon contributions to the diffractive structure function in DIS at HERA is presented. The recently published data allow to determine the only free parameter of the analysis related to the ratio of the RRIP and IP IP IP couplings. The large value of this ratio is prefered which is in agreement with analyses of soft hadronic interactions. The role of the subleading Reggeons as well as pions for the fast forward neutron production in diffractive processes is estimated. The forward πN state production is also discussed.
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Papers by A. Szczurek