arXiv subjects

Piotr Lebiedowicz

Publications and source records attributed to Piotr Lebiedowicz.

86 records · Page 5Linked to original sources

arXiv2012

Exclusive production of meson pairs and resonances in proton-proton collisions

We report a study of the central exclusive production of $π^{+} π^{-}$ and $K^{+}K^{-}$ pairs in high energy hadron-hadron collisions. The amplitude is calculated in the Regge approach including both pomeron and secondary reggeon exchanges and absorption effects due to proton-proton interaction and $ππ$ ($KK$) rescattering. We discuss a measurement of exclusive production of a scalar $χ_{c0}$ meson via $χ_{c0} \to π^{+} π^{-}$, $K^{+} K^{-}$ decay. We find that the relative contribution of resonance states and the $ππ$ ($KK$) continuum strongly depend on the cut on pion (kaon) transverse momentum. We compare the results with the existing experimental data and present predictions for the RHIC, Tevatron and LHC colliders. We discuss also the $f_{2}(1270)$ meson production mediated by an effective tensor pomeron exchanges.

hep-ph↗

arXiv2012

Exclusive meson pair production in proton-proton collisions

We present a study of the exclusive production of meson pairs in the four-body $pp \to pp π^{+} π^{-}$, $pp K^{+}K^{-}$ reactions at high energies which constitute an irreducible background to resonance states (e.g. $ϕ$, $f_{2}(1270)$, $f_{0}(1500)$, $f_{2}'(1525)$, $χ_{c0}$). We consider central diffractive contribution mediated by Pomeron and Reggeon exchanges and new diffractive mechanism of emission of pions/kaons from the proton lines. We include absorption effects due to proton-proton interaction and pion/kaon rescattering. Predictions for the total cross section and differential distributions in pion/kaon rapidity and transverse momentum as well as two-pion/kaon invariant mass are presented for the RHIC, Tevatron and LHC colliders. Finally we consider a measurement of exclusive production of a scalar $χ_{c0}$ meson via $χ_{c0} \to π^{+} π^{-}$, $K^{+} K^{-}$ decay.

hep-ph↗

arXiv2012

Diffractive pQCD mechanism of exclusive production of $W^+ W^-$ pairs in proton-proton collisions

We present a study of central exclusive production of $W^+W^-$ pairs in proton-proton collisions at the LHC. We compare the contribution of the $γγ\to W^+ W^-$ mechanism with a new mechanism of exclusive diffractive production through the $gg \to W^+ W^-$ subprocess with intermediate virtual Higgs boson and quark box diagrams. The amplitude for the latter process is expressed in terms of the off-diagonal unintegrated gluon distribution functions. Several observables related to this process are calculated. The phase space integrated diffractive contribution when separated is only a small fraction of fb compared to 115.4 fb of the $γγ$-contribution without absorption. This opens a possibility of efficient searches for anomalous boson $γW^+ W^-$ and $γγW^+ W^-$ couplings due to new physics beyond Standard Model.

hep-ph↗

arXiv2012

Exclusive scalar $f_0(1500)$ meson production

We evaluate differential distributions for exclusive scalar $f_0(1500)$ meson (glueball candidate) production. Both QCD diffractive, pion-pion meson exchange current (MEC) components as well as double-diffractive mechanism with intermediate pionic loop are calculated. The pion-pion component, which can be reliably calculated, dominates close to the threshold while the diffractive component may take over only for larger energies. At the moment only upper limit for the QCD-diffractive component can be obtained. The diffractive component is calculated based on the Khoze-Martin-Ryskin approach proposed for diffractive Higgs boson production. Different unintegrated gluon distribution functions (UGDFs) from the literature are used. Rather large cross sections (due to pion-pion fusion) are predicted for PANDA energies, where the gluonic mechanism is shown to be negligible.

hep-ph↗

arXiv2011

Exclusive open strangeness production in the $pp \to pp K^{+} K^{-}$ reaction at high energies and a measurement of scalar $χ_{c0}$ meson

We discuss the results of exclusive $p p \to p p K^{+} K^{-}$ reaction at high energies which constitutes an irreducible background to three-body processes $p p \to p p M$, where $M=ϕ$, $f_{2}(1275)$, $f_{0}(1500)$, $f_{2}'(1525)$, $χ_{c0}$. We consider central diffractive contribution mediated by Pomeron and Reggeon exchanges including absorption effects due to proton-proton interaction and kaon-kaon rescattering. We make predictions for future experiments at RHIC, Tevatron and LHC. Differential distributions in invariant two-kaon mass, kaon rapidities and transverse momenta of kaons are presented. We discuss a measurement of exclusive production of scalar $χ_{c0}$ meson in the proton-(anti)proton collisions via $χ_{c0} \to K^{+}K^{-}$ decay. The corresponding amplitude for exclusive central diffractive $χ_{c0}$ meson production is calculated within the $k_{t}$-factorization approach.

hep-ph↗

arXiv2011

$pp \to pp K^{+}K^{-}$ reaction at high energies

We evaluate differential distributions for the four-body $p p \to p p K^{+} K^{-}$ reaction at high energies which constitutes an irreducible background to three-body processes $p p \to p p M$, where $M=ϕ$, $f_{2}(1275)$, $f_{0}(1500)$, $f_{2}'(1525)$, $χ_{c0}$. We consider central diffractive contribution mediated by Pomeron and Reggeon exchanges as well as completely new mechanism of emission of kaons from the proton lines. We include absorption effects due to proton-proton interaction and kaon-kaon rescattering. We compare our results with measured cross sections for the CERN ISR experiment. We make predictions for future experiments at RHIC, Tevatron and LHC. Differential distributions in invariant two-kaon mass, kaon rapidities and transverse momenta of kaons are presented. Two-dimensional distribution in $(y_{K^+}, y_{K^-})$ is particularly interesting. The higher the incident energy, the higher preference for the same-hemisphere emission of kaons. We find that the kaons from the new mechanism of emission directly from proton lines are produced rather forward and backward but the corresponding cross section is rather small. The processes considered here constitute a sizeable contribution to the total proton-proton cross section as well as to kaon inclusive cross section. We consider a measurement of exclusive production of scalar $χ_{c0}$ meson in the proton-proton collisions via $χ_{c0} \to K^{+}K^{-}$ decay. The corresponding amplitude for exclusive central diffractive $χ_{c0}$ meson production is calculated within the $k_{t}$-factorization approach. The influence of kinematical cuts on the signal-to-background ratio is discussed.

hep-ph↗

arXiv2011

Exclusive production of χ_{c}(0^{+}) meson and its measurement in the π^{+}π^{-} channel

We report on the results of a theoretical study of the central exclusive production of scalar $χ_{c}(0^{+})$ meson via $χ_{c0} \to π^{+}π^{-}$ decay in high-energy hadron collisions at the RHIC, Tevatron and LHC. The corresponding amplitude for exclusive double-diffractive $χ_{c0}$ meson production was obtained within the $k_{t}$-factorization approach including virtualities of active gluons and the cross section is calculated with unintegrated gluon distribution functions (UGDFs) known from the literature. The four-body $p p \to p p π^+ π^-$ reaction constitutes an irreducible background to the exclusive $χ_{c0}$ meson production. We include the absorption effects due to proton-proton interaction and pion-pion rescattering. Several differential distributions for $pp(\bar{p}) \to pp(\bar{p})χ_{c0}$ process, including the absorptive corrections, were calculated. The influence of kinematical cuts on the signal-to-background ratio is investigated.

hep-ph↗

arXiv2011

Measurement of exclusive production of scalar $χ_{c0}$ meson in proton-(anti)proton collisions via $χ_{c0} \to π^{+}π^{-}$ decay

We consider a measurement of exclusive production of scalar $χ_{c}(0^{++})$ meson in the proton-proton collisions at LHC and RHIC and in the proton-antiproton collisions at the Tevatron via $χ_{c0} \to π^{+}π^{-}$ decay. The corresponding amplitude for exclusive double-diffractive $χ_{c0}$ meson production was obtained within the $k_{t}$-factorization approach including virtualities of active gluons and the corresponding cross section is calculated with unintegrated gluon distribution functions (UGDFs) known from the literature. The four-body $p p \to p p π^+ π^-$ reaction constitutes an irreducible background to the exclusive $χ_{c0}$ meson production. We calculate several differential distributions for $pp(\bar{p}) \to pp(\bar{p})χ_{c0}$ process including absorptive corrections. The influence of kinematical cuts on the signal-to-background ratio is investigated. Corresponding experimental consequences are discussed.

hep-ph↗

arXiv2011

Exclusive $pp \to nn π^{+}π^{+}$ reaction at LHC and RHIC

We evaluate differential distributions for the four-body $p p \to n n π^+ π^+$ reaction. The amplitude for the process is calculated in the Regge approach including many diagrams. We make predictions for possible future experiments at RHIC and LHC energies. Very large cross sections are found which is partially due to interference of a few mechanisms. Presence of several interfering mechanisms precludes extraction of the elastic $π^+ π^+$ scattering cross section. Absorption effects are estimated. Differential distributions in pseudorapidity, rapidity, invariant two-pion mass, transverse-momentum and energy distributions of neutrons are presented for proton-proton collisions at $\sqrt{s}$ = 500 GeV (RHIC) and $\sqrt{s}$ = 0.9, 2.36 and 7 TeV (LHC). Cross sections with experimental cuts are presented.

hep-ph↗

arXiv2010

Exclusive production of pi+ pi- pairs in proton-proton and proton-antiproton collisions

We report on a detailed investigation of four-body $p p \to p p π^+ π^-$ and $p \bar{p} \to p \bar{p} π^+ π^-$) reactions which constitute an irreducible background to three-body processes $p p \to p p M$, where $M$ is a broad resonance in the $π^+ π^-$ channel, e.g. $M=σ, ρ^{0}, f_{0}(980), f_{2}(1275), f_{0}(1500)$. We include double-diffractive contribution (both pomeron and reggeon exchanges) as well as the pion-pion rescattering contributions. The first process dominates at higher energies and small pion-pion invariant masses while the second becomes important at lower energies and higher pion-pion invariant masses. We compare our results with the experimental data. We make predictions for future experiments at PANDA, RHIC, Tevatron and LHC energies. The two-dimensional distribution in rapidity space of pions $(y_{π^+}, y_{π^-})$ is particularly interesting. The higher the incident energy, the higher preference for the same-hemisphere emission of pions. The processes considered constitute a sizeable contribution to the total nucleon-nucleon cross section as well as to pion inclusive cross section.

hep-ph↗

arXiv2009

Exclusive $pp \to pp π^{+}π^{-}$ reaction: from the threshold to LHC

We evaluate differential distributions for the four-body $p p \to p p π^+ π^-$ reaction which constitutes a irreducible background to three-body processes $p p \to p p M$, where $M$ are a broad resonances in the $π^+ π^-$ channel, e.g. $M=σ, ρ^{0}, f_{0}(980), f_{2}(1275), f_{0}(1500)$. We include both double-diffractive contribution (both pomeron and reggeon exchanges) as well as the pion-pion rescattering contribution. The first process dominates at higher energies and small pion-pion invariant masses while the second becomes important at lower energies and higher pion-pion invariant masses. The amplitude(s) is(are) calculated in the Regge approach. We compare our results with measured cross sections for the ISR experiments at CERN. We make predictions for future experiments at PANDA, RHIC, Tevatron and LHC energies. Differential distributions in effective two-pion mass, pion rapidities and transverse momenta of pions are presented. The two-dimensional distribution in $(y_{π^+}, y_{π^-})$ is particularly interesting. The higher the incident energy, the higher preference for the same-hemisphere emission of pions. The processes considered constitute a sizeable contribution to the total nucleon-nucleon cross section as well as to pion inclusive cross section.

hep-ph↗

arXiv2009

Exclusive scalar $f_0(1500)$ meson production for energy ranges available at the GSI Facility for Antiproton and Ion Research (GSI-FAIR) and at the Japan Proton Accelerator Research Complex (J-PARC)

We evaluate differential distributions for exclusive scalar $f_0(1500)$ meson (glueball candidate) production for $p \bar p \to N_1 N_2 f_0$ (FAIR@GSI) and $p p \to p p f_0$ (J-PARC@Tokai). Both QCD diffractive, pion-pion meson exchange current (MEC) components as well as double-diffractive mechanism with intermediate pionic loop are calculated for the first time in the literature. The pion-pion component, which can be reliably calculated, dominates close to the threshold while the diffractive component may take over only for larger energies. At the moment only upper limit for the QCD-diffractive component can be obtained. The diffractive component is calculated based on two-gluon impact factors as well as in the framework of Khoze-Martin-Ryskin approach proposed for diffractive Higgs boson production. Different unintegrated gluon distribution functions (UGDFs) from the literature are used. Rather large cross sections due to pion-pion fusion are predicted for PANDA energies, where the gluonic mechanism is shown to be negligible. The production of $f_0(1500)$ close to threshold could limit the so-called $πNN$ form factor in the region of larger pion virtualities. We discuss in detail the two-pion background to the production of the $f_0(1500)$ meson. We compare our result with the existing data of %the WA102 Collaboration.

nucl-th↗

arXiv2009

Low-energy pion-pion scattering in the $pp \to ppπ^{+}π^{-}$ and $p\bar p \to p\bar pπ^{+}π^{-}$ reactions

We evaluate the contribution of pion-pion rescattering to the $p p \to p p π^+ π^-$ and $p \bar p \to p \bar p π^+ π^-$ reactions. We compare our results with the close-to-threshold experimental data. The pion-pion rescattering contribution is found there to be negligible. The predictions for future experiments with PANDA detector at High Energy Storage Ring (HESR) in GSI Darmstadt are presented. It is discussed how to cut off the dominant Roper resonance and double-$Δ$ excitation mechanisms leading to the $p p π^+ π^-$ channel in final state. Differential distributions in momentum transfers, transverse momentum, effective two-pions mass, relative azimuthal angle between pions, and pion rapidities are presented.

nucl-th↗

arXiv2008

Exclusive scalar glueball $f_0(1500)$ production for FAIR and J-PARC energy range

We evaluate differential distributions for exclusive scalar $f_0(1500)$ production for $p \bar p \to N_1 N_2 f_0$ (FAIR@GSI) and $p p \to p p f_0$ (J-PARC@Tokai). Both QCD diffractive and pion-pion meson exchange current (MEC) components are included. Rather large cross sections are predicted. The pion-pion component, never discussed in the literature, dominates close to the threshold while the diffractive component takes over for larger energies. The diffractive component is calculated based on two-gluon impact factors as well as in the framework of Khoze-Martin-Ryskin approach proposed for diffractive Higgs boson production. Different unintegrated gluon distribution functions (UGDFs) from the literature are used. The production of $f_0(1500)$ close to threshold could limit the so-called $πNN$ form factor in the region of larger pion virtualities.

nucl-th↗