Search

The deconfined state of strongly interacting quarks and gluons, quark–gluon plasma, may be formed in relativistic ion collisions at sufficient temperature and energy density. The signatures of quark–gluon plasma formation were observed in heavy-ion collisions by studying meson production. In small-collision systems, such as , , , and , the volume and lifetime of the produced medium might be insufficient for observation of quark–gluon plasma effects. However various physics mechanisms reflecting initial state of the collision, cold nuclear matter effects, may lead to a collective-like behavior in small-collision systems without quark–gluon plasma formation. The nuclear modified parton distribution functions are considered to be an underlying physics mechanism of cold nuclear matter effects. This paper presents the comparison of meson production in , , , and collisions at GeV at midrapidity ( , measured by PHENIX, to PYTHIA calculations with nuclear modified parton distribution functions EPPS16 and CTEQ15. The meson production in collisions at GeV might be driven by mechanisms additional to nuclear modification of parton distribution functions. [ABSTRACT FROM AUTHOR]

We propose methods to produce gamma light source, muon and energetic meson beams such as charged and neutral Kaons, which are boosted to be collimated and with relatively long lifetime. The first type of method is based on asymmetric electron positron collisions with a center-of-mass energy of, e.g. 1020 MeV, and Kaons can be produced at a rate of 1 0 4 − 5 ∕ s. The electron and positron beams are either asymmetric in energy, e.g. 10 GeV electron beam with 26 MeV positron beam, or asymmetric in space, e.g. 10 GeV electron and positron beams collisions with an angle around 0.05 radius. Such proposals should be able to be achieved with a reasonable budget. The other type of method relies on TeV positron on target experiment, where Kaon beams can be achieved at around 1 0 7 per bunch crossing. Such Kaon beams are clean with small contamination, and can have great physics potential on, e.g. hyperon searches through Kaon nuclei collision, Kaon rare decay measurement, and Kaon proton or Kaon lepton collisions. The same technique can also be extended to other final states such as pions and tau leptons. [ABSTRACT FROM AUTHOR]

The differential expansion of the integral of elastic collisions of electrons with heavy neutral particles is derived under the assumption that the electron distribution function is symmetric with respect to the vector of the external electric field. [ABSTRACT FROM AUTHOR]

Weak decays of the vector D ∗ 0 and B (s) ∗ 0 mesons to the μ + μ - final state provide novel potential to test the Standard Model of particle physics. Such processes have extremely small branching fractions as the vector mesons are able to decay through electromagnetic and (for the D ∗ 0 meson) strong interactions. Nonetheless, the production of copious quantities of these particles in LHC collisions, and the ability to exploit experimental techniques that can suppress background to low levels, provides good potential to reach interesting sensitivity. The possibility to reconstruct these processes as part of the decay chain of B - or B c + mesons appears particularly attractive due to the clean experimental signature of the displaced vertex. Indeed, published LHCb data on B - → π - μ + μ - decays already implies a stringent limit on the branching fraction of D ∗ 0 → μ + μ - . Estimates are made on the achievable sensitivity to D ∗ 0 → μ + μ - and B (s) ∗ 0 → μ + μ - decays with the LHCb experiment. [ABSTRACT FROM AUTHOR]

Angular correlations of heavy-flavour and charged particles in high-energy proton–proton collisions are sensitive to the production mechanisms of heavy quarks and to their fragmentation as well as hadronisation processes. The measurement of the azimuthal-correlation function of prompt D mesons with charged particles in proton–proton collisions at a centre-of-mass energy of s = 13 TeV with the ALICE detector is reported, considering D 0 , D + , and D ∗ + mesons in the transverse-momentum interval 3 < p T < 36 GeV/ c at midrapidity ( | y | < 0.5 ), and charged particles with p T > 0.3 GeV/ c and pseudorapidity | η | < 0.8 . This measurement has an improved precision and provides an extended transverse-momentum coverage compared to previous ALICE measurements at lower energies. The study is also performed as a function of the charged-particle multiplicity, showing no modifications of the correlation function with multiplicity within uncertainties. The properties and the transverse-momentum evolution of the near- and away-side correlation peaks are studied and compared with predictions from various Monte Carlo event generators. Among those considered, PYTHIA8 and POWHEG+PYTHIA8 provide the best description of the measured observables. The obtained results can provide guidance on tuning the generators. [ABSTRACT FROM AUTHOR]

In this work, we present the results of a component-level analysis with Monte Carlo simulations, which aid the interpretation of recent ALICE results of the azimutal correlation distribution of prompt D mesons with charged hadrons in pp and p–Pb collisions at s NN = 5.02 TeV. Parton-level contributions and fragmentation properties are evaluated. Charm and beauty contributions are compared in order to identify the observables that serve as sensitive probes of the production and hadronisation of heavy quarks. [ABSTRACT FROM AUTHOR]

We explore the system size dependence of heavy-quark-QGP interaction by studying the heavy flavor meson suppression and elliptic flow in Pb–Pb, Xe–Xe, Ar–Ar and O–O collisions at the LHC. The space-time evolution of the QGP is simulated using a (3 + 1) -dimensional viscous hydrodynamic model, while the heavy-quark-QGP interaction is described by an improved Langevin approach that includes both collisional and radiative energy loss inside a thermal medium. Within this framework, we provides a reasonable description of the D meson suppression and flow coefficients in Pb–Pb collisions, as well as predictions for both D and B meson observables in other collision systems yet to be measured. We find a clear hierarchy for the heavy meson suppression with respect to the size of the colliding nuclei, while their elliptic flow coefficient relies on both the system size and the geometric anisotropy of the QGP. Sizable suppression and flow are predicted for both D and B mesons in O–O collisions, which serve as a crucial bridge of jet quenching between large and small collision systems. Scaling behaviors between different collision systems are shown for heavy meson suppression factor and the bulk-eccentricity-rescaled heavy meson elliptic flow as functions of the number of participant nucleons in heavy-ion collisions. [ABSTRACT FROM AUTHOR]

The exclusive J / Ψ and Υ photoproduction in fixed - target collisions at the LHC and ep(A) collisions at the Electron ion collider in China (EicC) is investigated considering different models for the treatment of the vector meson production at low energies, close to the threshold. Results for the total cross sections and associated distributions are presented. We predict a large number of J / Ψ events at the LHC in the rapidity range covered by the LHCb detector. For the EicC, our predictions point out that a detailed analysis of the near threshold J / Ψ and Υ photoproduction is feasible. Moreover, our results indicate that the modeling of the near threshold vector meson production can be constrained by future experimental analyzes at the LHC and EicC. [ABSTRACT FROM AUTHOR]

The physics goal of the strong interaction program of the NA61/SHINE experiment at the CERN Super Proton Synchrotron (SPS) is to study the phase diagram of hadronic matter by a scan of particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents differential inclusive spectra of transverse momentum, transverse mass and rapidity of π - mesons produced in central 40 Ar+ 45 Sc collisions at beam momenta of 13A, 19A, 30A, 40A, 75A and 150 A Ge V / c . Energy and system size dependence of parameters of these distributions – mean transverse mass, the inverse slope parameter of transverse mass spectra, width of the rapidity distribution and mean multiplicity – are presented and discussed. Furthermore, the dependence of the ratio of the mean number of produced pions to the mean number of wounded nucleons on the collision energy was derived. The results are compared to predictions of several models. [ABSTRACT FROM AUTHOR]

The measurements of the inclusive J / ψ yield at midrapidity (| y | < 0.9) and forward rapidity (2.5 < y < 4) in Pb–Pb collisions at s NN = 5.02 TeV with the ALICE detector at the LHC are reported. The inclusive J / ψ production yields and nuclear modification factors, R AA , are measured as a function of the collision centrality, J / ψ transverse momentum (p T), and rapidity. The J / ψ average transverse momentum and squared transverse momentum (〈 p T 〉 and 〈 p T 2 〉) are evaluated as a function of the centrality at midrapidity. Compared to the previous ALICE publications, here the entire Pb–Pb collisions dataset collected during the LHC Run 2 is used, which improves the precision of the measurements and extends the p T coverage. The p T -integrated R AA shows a hint of an increasing trend towards unity from semicentral to central collisions at midrapidity, while it is flat at forward rapidity. The p T -differential R AA shows a strong suppression at high p T with less suppression at low p T where it reaches a larger value at midrapidity compared to forward rapidity. The ratio of the p T -integrated yields of J / ψ to those of D0 mesons is reported for the first time for the central and semicentral event classes at midrapidity. Model calculations implementing charmonium production via the coalescence of charm quarks and antiquarks during the fireball evolution (transport models) or in a statistical approach with thermal weights are in good agreement with the data at low p T. At higher p T , the data are well described by transport models and a model based on energy loss in the strongly-interacting medium produced in nuclear collisions at the LHC. [ABSTRACT FROM AUTHOR]

The experimental transverse momentum spectra of the charged pions and kaons, protons and antiprotons, produced at midrapidity in inelastic p + p collisions at (s) 1 / 2 = 2. 7 6 , 5.02, and 7 TeV, measured by ALICE collaboration, are analyzed systematically using the thermodynamically consistent Tsallis distribution function as well as Hagedorn function with the embedded transverse flow. To compare directly the results obtained from combined (simultaneous) fits with the above theoretical model functions of midrapidity spectra of the charged pions and kaons, protons and antiprotons in p + p collisions at (s) 1 / 2 = 2. 7 6 , 5.02, and 7 TeV, we use the optimal identical fitting p t ranges (p t ≥ 0. 5 GeV / c) in p + p collisions at (s) 1 / 2 = 2. 7 6 , 5.02, and 7 TeV. The parameter q increases consistently for all the particle species with increasing (s) 1 / 2 of p + p collisions from 2.76 to 5.02 TeV, remaining practically constant within fit errors in the collision energy range (s) 1 / 2 = 5 –7  TeV, suggesting probably a saturation and limiting behavior of the q value in p + p collisions at (s) 1 / 2 > 5  TeV. Approximate equality of the extracted nonextensivity parameter q for the pions and kaons (q (pions) ≈ q (kaons)) and relation q (mesons) > q (baryons) are obtained in p + p collisions at (s) 1 / 2 = 2. 7 6 , 5.02, and 7 TeV. Very negligible transverse (radial) flow velocity (consistent with zero value within the fit errors) is obtained in p + p collisions at (s) 1 / 2 = 2. 7 6 , 5.02, and 7 TeV from fitting the p t distributions of the charged pions and kaons, protons and antiprotons with the Hagedorn formula with the embedded transverse flow in the selected optimal identical p t ranges as well as in the full measured p t ranges. [ABSTRACT FROM AUTHOR]

The pT-differential non-linear flow modes, v4,22, v5,32, v6,33 and v6,222 for π±, K±, K S 0 , p + p ¯ , Λ + Λ ¯ and ϕ-meson have been measured for the first time at s NN = 5.02 TeV in Pb-Pb collisions with the ALICE detector at the Large Hadron Collider. The results were obtained with a multi-particle technique, correlating the identified hadrons with reference charged particles from a different pseudorapidity region. These non-linear observables probe the contribution from the second and third order initial spatial anisotropy coefficients to higher flow harmonics. All the characteristic features observed in previous pT-differential anisotropic flow measurements for various particle species are also present in the non-linear flow modes, i.e. increase of magnitude with increasing centrality percentile, mass ordering at low pT and particle type grouping in the intermediate pT range. Hydrodynamical calculations (iEBE-VISHNU) that use different initial conditions and values of shear and bulk viscosity to entropy density ratios are confronted with the data at low transverse momenta. These calculations exhibit a better agreement with the anisotropic flow coefficients than the non-linear flow modes. These observations indicate that non-linear flow modes can provide additional discriminatory power in the study of initial conditions as well as new stringent constraints to hydrodynamical calculations. [ABSTRACT FROM AUTHOR]

We critically discuss fragmentation of quarks or antiquarks to massive particles (mesons or baryons) in proton–proton collisions. Both heavy and light quark/antiquark fragmentations are discussed using universal z-dependent fragmentation functions. Different scenarios of how to define the z variable are considered: as a fraction of energy, momentum or light-cone momentum of the parent quark/antiquark. Also, a choice of the direction of motion of hadron with respect to the parent parton must be made in the simplest approach. Energy and flavor violation is discussed for the region of small pt and/or center-of-mass y ∼ 0. Results of different approaches are compared. We show that at the LHC energies all schemes become consistent for D-meson transverse momenta larger than 2 GeV. Relations to results from the literature are made. We present some examples for production of D mesons from light and charm quarks/antiquarks. Emission with respect to the direction of motion lowers the cross section of D mesons at larger rapidities compared to the traditional approach (). As illustrated here the effect of using different prescriptions is particularly large at low energies (fixed target experiments). [ABSTRACT FROM AUTHOR]

The production yields of non-prompt D s + mesons, namely D s + mesons from beauty-hadron decays, were measured for the first time as a function of the transverse momentum (p T) at midrapidity (| y | < 0.5) in central and semi-central Pb–Pb collisions at a centre-of-mass energy per nucleon pair s NN = 5.02 TeV with the ALICE experiment at the LHC. The D s + mesons and their charge conjugates were reconstructed from the hadronic decay channel D s + → ϕ π + , with ϕ → K − K + , in the 4 < p T < 36 GeV / c and 2 < p T < 24 GeV / c intervals for the 0–10% and 30–50% centrality classes, respectively. The measured yields of non-prompt D s + mesons are compared to those of prompt D s + and non-prompt D 0 mesons by calculating the ratios of the production yields in Pb–Pb collisions and the nuclear modification factor R AA. The ratio between the R AA of non-prompt D s + and prompt D s + mesons, and that between the R AA of non-prompt D s + and non-prompt D 0 mesons in central Pb–Pb collisions are found to be on average higher than unity in the 4 < p T < 12 GeV / c interval with a statistical significance of about 1.6 σ and 1.7 σ , respectively. The measured R AA ratios are compared with the predictions of theoretical models of heavy-quark transport in a hydrodynamically expanding QGP that incorporate hadronisation via quark recombination. [ABSTRACT FROM AUTHOR]

Very precise high-statistics data furnished by experiments at the Large Hadron Collider at CERN and the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, as well as a few smaller experiments, have definitely brought the field into the precision era. This topical issue summarises some of the results realised thanks to the COST Action CA15213, which was running under the acronym THOR - short for I Theory of hot matter and relativistic heavy-ion collisions i - from November 2016 until April 2021. [Extracted from the article]

We investigate the contribution of partonic interactions between incident nucleons and produced mesons to the dilepton continuum in heavy-ion reactions. A schematic model is employed in order to calculate the resulting Drell–Yan yield as a function of collision energy and for different scenarios concerning the formation of hadrons. The secondary Drell–Yan process is found to be significant for invariant masses m ≈ 1. 5 GeV in central A + A collisions around s NN ≈ 1 5 − 2 0 GeV, but less so at much lower or much higher energies. Secondary Drell–Yan dileptons should be observable in experiments due to their distinct rapidity dependence as a characteristic deviation from the well-known (primary) Drell–Yan contribution due to N + N interactions. The predicted strong dependence of the secondary Drell–Yan contribution on the nuclear collision energy can be used to experimentally probe the effective hadronic formation time of secondaries. [ABSTRACT FROM AUTHOR]

It is advocated that geometry of the interaction region of two heavy nuclei colliding at large impact parameters is important for the relative role of light-by-light scattering and QCD-initiated processes. Exclusive production of resonances is possible by dense electromagnetic fields in the interior space between the nuclei. The cross-section of the two-photon processes is evaluated and some examples are considered. It is speculated that the exclusive production of ρ 0 -mesons by "two-photon" processes forbidden by the Landau–Yang rule may be allowed within strong magnetic fields due to odd number of photons becoming involved. [ABSTRACT FROM AUTHOR]

Abstract The cross sections for ϒ(1S), ϒ(2S), and ϒ(3S) production in lead–lead (PbPb) and proton–proton (pp) collisions at s NN = 5.02 TeV have been measured using the CMS detector at the LHC. The nuclear modification factors, R AA , derived from the PbPb-to- p p ratio of yields for each state, are studied as functions of meson rapidity and transverse momentum, as well as PbPb collision centrality. The yields of all three states are found to be significantly suppressed, and compatible with a sequential ordering of the suppression, R AA (ϒ (1S)) > R AA (ϒ (2S)) > R AA (ϒ (3S)). The suppression of ϒ(1S) is larger than that seen at s NN = 2.76 TeV , although the two are compatible within uncertainties. The upper limit on the R AA of ϒ (3 S) integrated over p T , rapidity and centrality is 0.096 at 95% confidence level, which is the strongest suppression observed for a quarkonium state in heavy ion collisions to date. [ABSTRACT FROM AUTHOR]

Abstract Inclusive ϒ(1S) and ϒ(2S) production have been measured in Pb–Pb collisions at the centre-of-mass energy per nucleon–nucleon pair s NN = 5.02 TeV, using the ALICE detector at the CERN LHC. The ϒ mesons are reconstructed in the centre-of-mass rapidity interval 2.5 < y < 4 and in the transverse-momentum range p T < 15 GeV/ c , via their decays to muon pairs. In this Letter, we present results on the inclusive ϒ(1S) nuclear modification factor R AA as a function of collision centrality, transverse momentum and rapidity. The ϒ(1S) and ϒ(2S) R AA , integrated over the centrality range 0–90%, are 0.37 ± 0.02 (stat) ± 0.03 (syst) and 0.10 ± 0.04 (stat) ± 0.02 (syst) , respectively, leading to a ratio R AA ϒ (2S) / R AA ϒ (1S) of 0.28 ± 0.12 (stat) ± 0.06 (syst). The observed ϒ(1S) suppression increases with the centrality of the collision and no significant variation is observed as a function of transverse momentum and rapidity. [ABSTRACT FROM AUTHOR]

Abstract These conferences proceedings summarize the experimental findings of collective effects in nuclear collisions, as presented at the Quark Matter 2018 conference. [ABSTRACT FROM AUTHOR]

Abstract The measurements of open charm production was proposed as an important tool to investigate the properties of the hot and dense matter formed in nucleus-nucleus collisions as well as to provide the means for model independent interpretation of the existing data on J/ ψ suppression. Recently, the experimental setup of the NA61/SHINE experiment was supplemented with a Vertex Detector which was motivated by the importance and the possibility of the first direct measurements of open charm meson production in heavy ion collisions at SPS energies. First test data taken in December 2016 on Pb+Pb collisions at 150 A GeV/ c allowed to validate the general concept of D0 meson detection via its D0 → π + + K − decay channel and delivered a first indication of open charm production. The physics motivation of open charm measurements at SPS energies, pilot results on open charm production, and finally, the future plans of open charm measurements in the NA61/SHINE experiment after LS2 are presented. [ABSTRACT FROM AUTHOR]

Abstract The spin alignment of ϕ and K *0 vector mesons is sensitive to different hadronization scenarios and the vorticity of the colliding system. We present STAR's measurement of global spin alignment of ϕ and K *0 for Au + Au collisions at s N N = 7.7 (ϕ meson only), 11.5, 14.5 (K *0 meson only) 19.6, 27, 39 and 200 (ϕ meson only) GeV. The alignment is quantified by the diagonal spin density matrix element, ρ 00 , with respect to the normal of the event plane. The ρ 00 measurement based on the 1st- and 2nd-order event planes are presented. The results are shown as a function of transverse momentum, collision centrality and beam energy The implications of our results on the vorticity and the hadronization scenarios are discussed. [ABSTRACT FROM AUTHOR]

Abstract The study of charm production in heavy-ion collisions is considered an excellent probe for the properties of the hot and dense medium created in heavy-ion collisions. Measurements of D 0-meson nuclear modification factor can provide strong constraints into the mechanisms of in-medium energy loss and charm flow in the medium. The measurement of D 0-meson elliptic flow in pPb collisions helps us understand the strength of charm quarks coupling to significantly reduced systems which demonstrate hydrodynamic properties. In this paper, the measurements of the D 0-meson nuclear modification factor in PbPb collisions at 5.02 TeV together with the new measurement of D 0-meson elliptic flow in high multiplicity pPb collisions at 5.02 TeV using the two-particle correlation method will be presented. [ABSTRACT FROM AUTHOR]

We expose the current experimental and theoretical situation of the interesting case of the production of ϕ mesons in up to very high energy collisions of hadrons on both nucleon and nuclear targets, and we present a quantitatively good theoretical description of the corresponding experimental data, based on the formalism of the well established Quark–Gluon String Model, that has proved to be valid for a wide energy range. All the available experimental data for ϕ -meson production in hadron–nucleon collisions on the spectra of secondary ϕ , and on the ratios of ϕ / π − and ϕ / K − production cross-sections, as well the corresponding ones for ϕ -meson production on nuclear targets, are considered. In particular, it is seen that the production of ϕ -mesons on nuclear targets presents unusually small shadow corrections for the inclusive density in the central rapidity region. [ABSTRACT FROM AUTHOR]

Abstract We describe the Belle II detector at the SuperKEKB electron–positron accelerator. SuperKEKB operates at the energy of the ϒ (4 S) resonance where pairs of B mesons are produced in a coherent quantum mechanical state with no additional particles. Belle II, the first Super B factory detector, aims to achieve performance comparable to the original Belle and BaBar B factory experiments, which first measured the large CP violating effects in the B meson system, with much higher luminosity collisions and larger beam-induced backgrounds. [ABSTRACT FROM AUTHOR]

Abstract Hidden charm mesons continue playing an essential role as relevant probes to understand the evolution of partonic matter. It is expected that the charmonia that survived the quark-gluon plasma phase suffer collisions with other particles composing the hadronic matter. In this work, we intend to contribute on this subject by presenting an updated study about the interactions of J / ψ with surrounding hadronic medium. The meson-meson interactions are described with a S U (4) effective Lagrangian, and within the framework of unitarized coupled channel amplitudes projected onto s -wave. The symmetry is explicitly broken to S U (3) by suppression of the interactions driven by charmed mesons. We calculate the cross sections for J / ψ scattering by light pseudoscalar mesons (π , K , η) and vector mesons (ρ , K ⁎ , ω), as well as their inverse processes. Keeping the validity of this present approach in the low CM energy range, the most relevant channels are evaluated and a comparison of the findings with existing literature is performed. [ABSTRACT FROM AUTHOR]

The photoproduction of J/ψ mesons off nuclei at the energies of 8 and 11 GeV, which are close to the threshold for their production on a free nucleon, is considered on the basis of the first-collisionmodel relying on the nuclear spectral function and including incoherent processes of charmonium production in photon-nucleon collisions. The model takes into account the absorption of final J/ψ mesons, the binding of target nucleons, and their Fermi motion, as well as the effect of the scalar J/ψ-nucleus potential (or the inmedium shift of the J/ψ-meson mass) on these processes. Under various assumptions on the magnitude of this shift, the momentum dependences of various observables, such as the relative transparency of carbon and gold nuclei and the J/ψ-meson yields, are calculated for meson production on these nuclei. The observables in question include the relative transparencies of these nuclei to J/ψ mesons and the absolute and relativemeson yields from them. It is shown that, at the energy of 11 GeV, which is above the threshold, the first observable is virtually independent of the in-medium change in the J/ψ-meson mass. At the same time, it is moderately sensitive to this change at the subthreshold energy of 8 GeV. On the other hand, it is shown that, at these photon energies, the absolute and relative values of the differential cross sections, especially for the the heavy nucleus of 197 Au, in the momentum range of 4-6 GeV/с are highly sensitive to the in-medium change in the J/ψ-meson mass. Therefore, the present calculations can be used to determine the unknown shift of the J/ψ-meson mass in nuclei by means of comparing their results with data expected from experiments in Hall C at the Continuous Electron Beam Accelerator Facility (CEBAF, USA) upgraded to the energy of 12 GeV. [ABSTRACT FROM AUTHOR]

We make predictions for cross sections of ρ and ϕ vector meson photoproduction in ultraperipheral Xe–Xe collisions at s N N = 5.44 TeV . Analyzing the momentum transfer distribution of ρ mesons in this process, we explore the feasibility of extracting the nuclear density of 129 Xe, which is needed in searches for dark matter with Xenon-based detectors. [ABSTRACT FROM AUTHOR]

We study inclusive charm and bottom production, for both D and B mesons, in p–Pb collisions at the LHC. Numerical results for p T -differential production cross sections are obtained at next-to-leading-order in the general-mass variable-flavour-number scheme. We compare our results with recent data from ALICE, LHCb and CMS at a centre-of-mass energy of 5 TeV and find good agreement. A comparison with p–p cross sections does not reveal the presence of nuclear initial-state interaction effects that could be expected to become visible as deviations of the ratio of p–Pb and p–p cross sections from one. [ABSTRACT FROM AUTHOR]

A collisional model for hadron resonances appearing in hadron collisions is proposed. The given approach leads to a simple explanation of the scalar sector below 1 GeV with correct predictions for masses and dominant decay modes. [ABSTRACT FROM AUTHOR]

The article focuses on an analysis of nuclei collisions with determination of different accelerators. Topics discussed include analysis of ultraperipheral collisions among hadrons by researchers with particle accelerators; observation of photon flux advantage over heavy ions with nuclear charge in comparison with protons that leads to an exchange of protons among ions; and assessment of gluon distribution conditions among protons with an exchange of mesons.

This is an addendum to the article JHEP 11 (2015) 205 [1]. The figures 3 (right), 4 (right) and 5 are updated with published results on non-prompt J/ ψ-meson production from the CMS collaboration [2]. [ABSTRACT FROM AUTHOR]

We study the correlations of D mesons produced in p+p and p+Pb collisions. These are found to be sensitive to the effects of the cold nuclear medium and the transverse momentum ( $ p_{{\rm T}}$ ) regions we are looking into. In order to put this on a quantitative footing, as a first step we analyse the azimuthal correlations of D meson-charged hadron (Dh), and then predict the same for D meson-anti D meson ( $ {\rm D}\overline{{\rm D}}$ ) pairs in p+p and p+Pb collisions with strong coupling at leading order $\mathcal{O}(\alpha_{{\rm s}}^{2})$ and next-to-leading order $\mathcal{O}(\alpha_{{\rm s}}^{3})$ , which includes space-time evolution (in both systems) as well as cold nuclear matter effects (in p+Pb). This also sets the stage and baseline for the identification and study of medium modification of azimuthal correlations in relativistic collision of heavy nuclei at the Large Hadron Collider. [ABSTRACT FROM AUTHOR]