Trimuon production by antineutrinos

We examine the electromagnetic and hadronic contribution to antineutrino trimuon production. The μ⁺μ⁺μ^? rate and distributions are in reasonable agreement with the experimental values quoted by the CDHS group for their eight events. More data is required before any detailed comparison can be made between theory and experiment.     

Strange particle production at RHIC

We report STAR measurements of mid-rapidity yields for the Λ , , K _S ⁰ , Ξ ⁻, , Ω ⁻, particles in Cu + Cu and Au + Au  GeV collisions. We show that at a given number of participating nucleons, bulk strangeness production is higher in Cu + Cu collisions compared to Au + Au collisions at the same center of mass energy, counter to predictions from the Canonical formalism. We compare both the Cu + Cu and Au + Au yields to AMPT and EPOS predictions, and find they reproduce key qualitative aspects of the data. Finally, we investigate other scaling parameters and find bulk strangeness production for both the measured data and theoretical predictions, scales better with the number participants that undergo more than one collision.     

Trilepton production by neutrinos and antineutrinos

We calculate the electromagnetic and hadronic contributions to neutrino production of μ^?e⁺e^? events and antineutrino production of μ⁺e⁺e^? events. Due to an increase in cross section and acceptance, these rates are much larger in bubble-chamber experiments than the corresponding rates for trimuon events in counter experiments. Verification of these rates would confirm our understanding of the physics behind trilepton events. We stress the importance of measuring also a rate for μ^?e^? events to determine the cross section for the associated production of charmed particles.     

Strange particle production from SIS to LHC

A review of meson emission in heavy-ion collisions at incident energies from SIS up to collider energies is presented. A statistical model assuming chemical equilibrium and local strangeness conservation (i.e. strangeness conservation per collision) explains most of the observed features, e.g. the different centrality dependences of pions and kaons. Furthermore, the independence of theK ⁺ toK ^- ratio on the number of participating nucleons observed between SIS and relativistic heavy-ion collider (RHIC) is consistent with this model. The observed maximum in theK ⁺/π⁺ excitation function is also seen in the ratio of strange to non-strange particle production. The appearance of this maximum around 30 A.GeV is due to the energy dependence of the chemical freeze-out parametersT and μ_B.     

Strange particle production in the hadrochemical model

Strange particle production in heavy ion collisions is calculated in the framework of a hadrochemical model. It is compared with the results of cascade and fireball model calculations and experimental data. The importance of πN and πΔ collisions in producing kaons and hyperons is pointed out.     

Strange particle production in relativistic collisions of heavy ions

This review examines data on strange particle production in Pb + Pb collisions obtained in heavy ion experiments at CERN SPS. The yields of K, Λ, Ξ and Ω are considered, as well as their rapidity and transverse mass distributions, depending on the centrality of Pb + Pb collisions at SPS energies. Experimental results are compared with predictions of the statistical nuclear fireball and microscopic parton -string models. We discuss in detail the experimentally observed effect of strangeness enhancement in nucleus-nucleus collisions as compared to nucleon-nuclear interactions and its interpretation within the framework of various theoretical models. Also, we analyze the behavior of hyperon yields and nuclear modification factors in passing from SPS to RHIC energies.     

Strange particle production and charmed particle search in the gargamelle neutrino experiment

Data is given for single and multiple strange particle production in neutrino reactions in both charged and neutral current channels. A total of 15000 neutrino and antineutrino events has been examined for possible evidence of semi-leptonic decay of a charmed particle. One candidate has been observed. Upper limits on charmed particle production cross-sections are given as a function of the neutrino energy and the invariant mass of the final state hadrons.     

Strange particle production in proton-nucleus reactions at ultrarelativistic energies

Enhanced yields of lambdas and other strange hadrons in experiments on nuclear targets at incident energies of 200 GeV have been recently reported by several experimental groups. We calculated events for proton projectiles on different targets in the framework of the relativistic quantum molecular dynamics approach which is based on string excitation and fragmentation with subsequent hadronic collisions. Here we address the question whether the experimentally found lambda enhancement in hadron-nucleus collisions can be understood by interactions of secondary hadrons formed in the target nucleus. Our results for Λ's, kaons and \(\bar \Lambda 's\) agree well with the experimental measurements. We find a doubling of lambda production in the target fragmentation region forp collisions on heavy targets due to nuclear cascading of the produced mesons. Resonances play an important role in creating strange quark pairs confirming earlier findings of their outstanding role inAA collisions.     

Strange particle production at RHIC in the dual parton model

We compute the mid-rapidity densities of pions, kaons, baryons and antibaryons in Au-Au collisions at GeV in the dual parton model supplemented with final state interaction (comovers interaction). The ratios ( ) increase between peripheral ( ) and central ( collisions by a factor 2.4 (2.0) for the , 4.8 (4.1) for the and 16.5 (13.5) for the . The ratio increases by a factor 1.3 in the same centrality range. A comparison with the available data is presented.Received: 28 April 2003, Published online: 11 July 2003     

Diffractive production of charmed strange mesons by neutrinos and antineutrinos

The diffractive production of charmed strangeD _s ^* and possiblyD _s mesons by neutrinos and antineutrinos on nucleons in hydrogen, deuterium and neon targets is observed. The slope parameter of thet distribution is 3.3±0.8 (GeV)^?2. The production rate per charged current neutrino interaction with an isoscalar target times the D _s ⁺ →φτ⁺ branching fraction is (1.03±0.27)×10^?4.     

Dilepton and trilepton production by antineutrinos and neutrinos in neon

A sample of over 25,000 fully measured neutrino and antineutrino charged current interactions in BEBC includes 192 dilepton candidates. The prompt signal after subtraction of background is 41 ±7µ⁺ e ^-, 35±7µ⁺µ^- events from \(\bar v\) interactions, and 32±7µ^-µ⁺ events from ν interactions. There are 2 trileptons, µ^-µ^- e ⁺ and µ^-µ^-µ⁺. Results are compared with other experimental data and with the standard model. Limits to prompt like sign µ⁺ e ⁺, µ⁺µ⁺ and µ^-µ^- signals are given and compared with other experiments and with theoretical calculations.     

Strange particle production mechanisms in proton—Proton collisions at RHIC

We present data on strange particle production in elementary proton-proton collisions at RHIC energies. Comparison to leading order and next-to-leading order (NLO) calculations shows that the fragmentation process is flavor dependent and that higher order corrections are needed to describe all spectra, in particular at these collision energies, which are modest compared to those at the Tevatron. A model (EPOS) which takes into account multiple scattering between projectile constituents seems to describe the data best.     

Strange particle production in nuclear collisions at 200 GeV per nucleon

Multiplicities and spectra of strange particles ( andK ^– produced in central³²S+S,³²S+Ag and³²S+Au collisions at 200 GeV per nucleon are presented and compared with data on strange particle production in protonnucleus and nucleon-nucleon interactions. It is shown that strangeness production in³²S+Ag collisions is enhanced by a factor of two, similar to that found previously in central³²S+S collisions.     

Strange particle production from π−p interactions at 1.69 GeV/c

The three-body final states $\text{Σ}{}^{\mathrm{\pm }}\text{π}{}^{\mathrm{?}}\text{K}{}^0\text{, Σ}{}^{\mathrm{<mtext>0</mtext>}}\text{π}{}^{\mathrm{<mtext>0</mtext>}}\text{K}{}^{\mathrm{+}}$ and $\text{Λπ}{}^{\mathrm{<mtext>0</mtext>}}\text{K}{}^{\mathrm{+0}}$ produced from πp interactions at 1.69 GeV/c are examined. The quasi-two-body state Λ(1405)K⁰ is discussed in detail. In particular, the spin of Λ(1405) is determined, via the method of Byers and Fenster, to be consistent with $\text{1}\text{2}$. The Σ^±π^? mass spectrum is compared to that produced by various zero-range and effective-range parametrizations and the Λ(1405) is found to have a mass of 1405 MeV and width of 45–55 MeV. Production and decay characteristics of the quasi-two-body states $\text{Σ(1385)}{}^{\mathrm{<mtext>0</mtext>}}\text{K}{}^{\mathrm{<mtext>0</mtext>}}$ are reported.     

Strange particle production in relativistic nucleus-nucleus collisions at RHIC and LHC energy regions

PACIAE, a parton and hadron cascade model, is utilized to systematically investigate strange particle production and strangeness enhancement in Au＋Au collisions and in Pb＋Pb collisions with the √SNN = 200 GeV at the RHIC and 2.76 TeV at the LHC, respectively. The experimental results at different centralities, using data from the STAR collaboration and the ALICE collaboration, are well described by the PACIAE model. This may represent the importance of the parton and hadron rescatterings, as well as the reduction mechanism for strange quark suppression, that are implemented in the PACIAE model.     

Strange particle production in relativistic nucleus-nucleus collisions in the RHIC BES energy region

The parton and hadron cascade model PACIAE is used to investigate strange particle production in Au + Au collisions at s~(1/2) = 62.4 GeV in different centralities and at s~(1/2) =39, 11.5 and 7.7 GeV in the most central collision, respectively. It is shown that the transverse momentum distributions of strange particles by the PACIAE model fit the RHIC Beam Energy Scan experimental results well.     

Strange particle production at the intersection of soft and hard processes at RHIC

Nuclear suppression factor and u ₂ measurements as a function of transverse momentum for neutral strange particles are shown and compared to particle identified spectra from PHENIX and WA98 and to models that attempt to describe the suppression of particles at moderate pt in central RHIC Au?Au collisions. It is shown that identified spectra carry additional information to the published charged particle spectra. In particular, dependencies of the R _AA and u ₂ values on the measured particle species will be discussed in the context of several models.     

Strange particle production in relativistic nucleus-nucleus collisions at RHIC and LHC energy regions

PACIAE, a parton and hadron cascade model, is utilized to systematically investigate strange particle production and strangeness enhancement in Au+Au collisions and in Pb+Pb collisions with the √s_NN=200 GeV at the RHIC and 2.76 TeV at the LHC, respectively. The experimental results at different centralities, using data from the STAR collaboration and the ALICE collaboration, are well described by the PACIAE model. This may represent the importance of the parton and hadron rescatterings, as well as the reduction mechanism for strange quark suppression, that are implemented in the PACIAE model.     

Determination of charm production cross-sections for neutrinos and antineutrinos

It is shown that existing data for production rates of opposite-sign dileptons by neutrinos and antineutrinos are mutually consistent when acceptance corrections are calculated using a standard four-quark parton model, and a flat fragmentation function for charmed quarks. Together with a corrected cross-section, model calculations which adequately describe the data are presented.