A collection of results is presented relevant for the analysis of azimuthal asymmetries in inclusive two-hadron production at BELLE. The aim of this overview is to provide theoretical ingredients necessary to extract the Collins effect fragmentation function. The latter arises within the Collins-Soper factorization formalism, which describes both the transverse momentum and Q^2 dependence of the cross section and its angular dependences at low and moderate transverse momentum. Since the Collins effect is not the only source of angular dependences, a discussion of various other effects is included. This concerns higher twist contributions, photon-Z-boson interference effects, radiative corrections, beam polarization and weak decays. Furthermore, different frames, transverse momentum weighting and ratios of asymmetries are discussed. These issues are all of relevance for the unambiguous measurement of the Collins effect.
With the first data being recorded at Belle II, we are at the brink of a new era in quark flavour physics. The many exciting new opportunities for Belle~II include a full angular analysis of inclusive ${\bar B \to X_{s} \, \ell^+\ell^-}$ which has the potential to reveal new physics, in particular by its interplay with the exclusive $b \to s \ell^+\ell^-$ counterparts studied extensively at LHCb. In this paper, we present fully updated Standard Model predictions for all angular observables necessary for this endeavour. These predictions are tailored to Belle II and include an elaborate study o…
In 2018 the Belle II experiment, aimed at detailed studies of B-mesons, started operation at the electron-positron collider SuperKEKB at KEK (Japan). This was preceded by a long and quite successful work of the B-factories of previous generations, including the Belle experiment for which Belle II is a successor. This experiment is unique and has no analogues or competitors in the world. The spectrum of problems it is aimed at is quite broad: from studies of hadronic states containing heavy quarks to precision measurements and searches for New Physics beyond the Standard Model. This review desc…
The Belle II physics potential for hadron spectroscopy, inputs to g-2, fragmentation functions, proton form factors, measurements of $α_s$ and hadronic $τ$ decays is outlined.
In this contribution we review the status of inclusive jet cross sections at hadron colliders in perturbative QCD, studying in particular the renormalisation and factorisation scale dependence of the one-jet inclusive cross section at NNLO.
Semi-inclusive processes are very promising to investigate $XYZ$ hadrons at the next generation of electron-hadron facilities, because they generally boast higher cross sections. We extend our formalism of exclusive photoproduction to semi-inclusive final states. The inclusive production cross sections for charged axial-vector $Z$ states from pion exchange are predicted. We isolate the contribution of $Δ$ resonances at small missing mass. Production near threshold is shown to be enhanced roughly by a factor of two compared to the exclusive reaction. We benchmark the model with data of semi-inc…
Data from the Belle Collaboration for associated production (with a light unpolarized hadron) and single-inclusive production of transversely polarized $Λ$-hyperons in $e^+e^-$ annihilation processes allowed to extract within a TMD approach, for the first time, the $Λ$ polarizing fragmentation function. Recent theoretical developments on the computation of cross sections for single-inclusive hadron production in $e^+e^-$ annihilation processes, within a Soft Collinear Effective Theory approach, combined with the CSS formalism for the double-hadron production case, can be used to perform a rene…
We present predictions for the inclusive production of leptons ($e^{\pm},μ^{\pm}$) originating from charm and bottom-hadrons at the CERN LHC in the general-mass variable-flavor-number scheme at next-to-leading order. Detailed numerical results are compared to data of the CMS, ATLAS and ALICE collaborations.
Semi-inclusive deep-inelastic scattering (SIDIS) at the Electron-Ion Collider will allow for precise mapping of the 3D momentum and spin structure of nucleons and nuclei over a large kinematic region. In this contribution, we demonstrate methods utilizing the hadronic final state and scattered electron, as well as machine learning, to more reliably reconstruct the virtual photon four momentum and SIDIS kinematics across the inclusive DIS coverage at the EIC.
We study the role of low momentum transfer (soft) interactions between high-transverse momentum heavy particles and beam remnants (spectators) in hadronic collisions. Such final-state interactions are power suppressed for single-particle inclusive cross sections whenever that particle is accompanied by a recoiling high-p_T partner whose momentum is not fixed. An example is the single-top inclusive cross section in top pair production. Final-state soft interactions in multi-particle inclusive cross sections, including transverse momentum distributions, however, produce leading power corrections…
The inclusive production of light mesons in pp-scattering is considered in the framework of reggeon phenomenology with supercritical Pomeron. Available low-energy data can be explained with three reggeon particles taken into account. With the obtained results rapidity and pseudorapidity distributions for light-meson production at LHC energies are predicted.
In this paper, we present an extraction of the contribution from the "{\it residual}" light charged hadrons to the inclusive unidentified light charged hadron fragmentation functions (FFs) at next-to-leading (NLO) and, for the first time, at next-to-next-to-leading order (NNLO) accuracy in perturbative QCD. Considering the contributions from charged pion, kaon and (anti)proton FFs from recent {\tt NNFF1.0} analysis of charged hadron FFs, we determine the small but efficient {\it residual} charged hadron FFs from QCD analysis of all available single inclusive unidentified charged hadron data se…
Inspired by the recent discovery of the $X(6900)$ meson at {\tt LHCb} experiment, we investigate the inclusive production rate of the $C$-odd fully-charmed tetraquarks associated with light hadrons at the $B$ factory within the nonrelativistic QCD (NRQCD) factorization framework. The short-distance coefficient is computed at lowest order in velocity and $α_s$. Employing the diquark-antidiquark model to roughly estimate the long-distance NRQCD matrix elements, we predict the rate for inclusive production of the $1^{+-}$ $T_{4c}$ state and discuss the observation prospects at {\tt Belle 2} exper…
The determination of the CKM element $V_{cb}$ from inclusive semileptonic $b\to c \ell \barν$ decays has reached a high precision thanks to a combination of theoretical and experimental efforts. Aiming towards even higher precision, we discuss two processes that contaminate the inclusive $V_{cb}$ determination; the $b\to u$ background and the contribution of the tauonic mode: $b\to c(τ\to μν\barν)\barν$. Both of these contributions are dealt with at the experimental side, using Monte-Carlo methods and momentum cuts. However, these contributions can be calculated with high precision within the …
We derive mass corrections for semi-inclusive deep inelastic scattering of leptons from nucleons using a collinear factorization framework which incorporates the initial state mass of the target nucleon and the final state mass of the produced hadron. The formalism is constructed specifically to ensure that physical kinematic thresholds for the semi-inclusive process are explicitly respected. A systematic study of the kinematic dependencies of the mass corrections to semi-inclusive cross sections reveals that these are even larger than for inclusive structure functions, especially at very smal…
The spin-dependent cross sections for semi-inclusive lepton-nucleon scattering are derived in the framework of collinear factorization, including the effects of masses of the target and produced hadron at finite momentum transfer squared Q^2. At leading order the cross sections factorize into products of parton distribution and fragmentation functions evaluated in terms of new, mass-dependent scaling variables. The size of the hadron mass corrections is estimated at kinematics relevant for future semi-inclusive deep-inelastic scattering experiments.
We investigate semi-inclusive photon-hadron production in the color glass condensate (CGC) framework at RHIC and the LHC energies in proton-proton (pp) and proton-nucleus (pA) collisions. We calculate the coincidence probability for azimuthal correlation of pairs of photon-hadron and show that the away-side correlations have a double-peak or a single-peak structure depending on trigger particle selection and kinematics. This novel feature is unique for semi-inclusive photon-hadron production compared to a similar measurement for double inclusive dihadron production in pA collisions. We obtain …
Our community has to apply {\em non}-perturbative QCD on different levels of flavor dynamics in strange, charm \& beauty hadrons and even for top quarks. We need {\em consistent} parameterization of the CKM matrix and describe weak decays of beauty hadrons with {\em many-body} final states. It is crucial to use the {\em Wilsonian} OPE as much as possible and discuss "duality" in the worlds of quarks and hadrons. The pole mass of heavy quarks is {\em not} well-defined on the {\em non}-perturbative level -- i.e., it is {\em not} Borel summable in total QCD. We need a novel team to combine the st…
We present a thorough phenomenological analysis of the experimental data from Belle Collaboration for the transverse $Λ$ and $\barΛ$ polarisation, measured in $e^+e^-$ annihilation processes, for the case of inclusive (plus a jet) and associated production with a light charged hadron. This allows for the first ever extraction of the quark polarising fragmentation function for a $Λ$ hyperon, a transverse momentum dependent distribution giving the probability that an unpolarised quark fragments into a transversely polarised spin-1/2 hadron.
The available data on the $D\overline{D}$ and inclusive hadronic cross sections in the $ψ(3770)$ region from the BaBar, Belle, BES-II, CLEO and KEDR experiments have been analyzed assuming that systematic uncertainties on cross sections measured by different detectors are not correlated. Four theoretical models predicting the $ψ(3770)$ line shape were considered for the $D\overline{D}$ channel. All of them gave satisfactory description of the data. The combined analysis of the $D\overline{D}$ and inclusive hadronic channel was performed using the model based on the vector dominance approach an…
Experimental data from Belle Collaboration for the transverse polarization of $Λ$'s measured in $e^+ e^-$ annihilation processes are used to extract the polarizing fragmentation function (FF) within a TMD approach. We consider both associated and inclusive $Λ$ production, showing a quite consistent scenario. Good separation in flavor is obtained, leading to four independent FFs. Predictions for SIDIS processes at the EIC, crucial for understanding their universality and evolution properties, are also presented.
In high density QCD the hadron production stems from decay of mini-jets that have the transverse momenta of the order of the saturation scale. It is shown in this paper that this idea is able to describe in a unique fashion both the inclusive hadron production for \sqrt{s} \geq 546 GeV including the first data from LHC and the deep inelastic scattering at HERA. Recently reported data from ALICE, CMS and ATLAS including inclusive charged-hadron transverse-momentum and multiplicity distribution in pp collisions are well described in our approach. We provide predictions for the upcoming LHC measu…
We investigate the resummation of large logarithmic perturbative corrections to hadron production in electron-positron annihilation and semi-inclusive deep-inelastic scattering. We find modest, but significant, enhancements of hadron multiplicities in the kinematic regimes accessible in present high-precision experiments. Our results are therefore relevant for the determination of hadron fragmentation functions from data for these processes.
We present the general expression, in terms of structure functions, of the cross section for the production of two hadrons in semi-inclusive deep-inelastic scattering. We analyze this process including full transverse-momentum dependence up to subleading twist and check, where possible, the consistency with existing literature.
It is demonstrated that the strong power-like scaling violation in the transverse momentum distribution of inclusive hadron production, observed by CDF Collaboration in $\bar{p}p$ collisions at Tevatron is caused by contribution of weak interaction. The contribution of weak interaction is increasing with energy at high energies.
Inclusive hadron production in $e^+e^-$ annihilation has long been used to study both single hadron fragmentation functions (FF) and dihadron fragmentation functions (DiFF). In particular, the polarized DiFFs can be accessed in electron-positron annihilation by measuring azimuthal correlations between two back-to-back pairs of hadrons in the center of mass system, where the relevant structure functions can be expressed as convolutions of two (polarized) DiFFs. Here we explore the advantages of measuring the inclusive back-to-back production of a single hadron on one side against a hadron pair …
We investigate the inclusive and semi-inclusive productions of spin-3/2 hadrons, such as $Ω$, in unpolarized $e^+ e^-$ annihilation. The general differential cross sections are expressed in terms of structure functions in accordance to the polarization of the hadron and the azimuthal modulations. We derive a complete definition of quark transverse momentum dependent (TMD) fragmentation functions (FFs) to spin-3/2 hadrons for the first time from the decomposition of the quark-quark correlation matrix at leading twist, 14 of which are newly defined corresponding to rank-3 tensor polarized hadron…
We show that a new beam-spin asymmetry appears in deep inelastic inclusive lepto-production at low transverse momenta when a hadron in the target fragmentation region is observed in association with another hadron in the current fragmentation region. The beam leptons are longitudinally polarized while the target nucleons are unpolarized. This asymmetry is a leading-twist effect generated by the correlation between the transverse momentum of quarks and the transverse momentum of the hadron emitted by the target. Experimental signatures of this effect are discussed.
We study the cross sections for the inclusive production of $ψ(2S)$ and $X(3872)$ hadrons in $pp$ collisions at the LHC at two different center-of-mass energies and compare with experimental data obtained by the ATLAS, CMS, and LHCb collaborations.
Theoretical description of inclusive tau lepton hadronic decay is performed in the framework of Dispersive approach to QCD. The significance of effects due to hadronization is demonstrated. The approach on hand is capable of describing experimental data on tau lepton decay in vector and axial-vector channels. The vicinity of values of QCD scale parameter obtained in both channels testifies to the self-consistency of developed approach.
