The strong coupling constant $\alpha_s(m_Z)$ is determined from inclusive jet and dijet cross sections in neutral-current deep-inelastic ep scattering (DIS) measured at HERA by the H1 collaboration using next-to-next-to-leading order (NNLO) QCD predictions. The dependence of the NNLO predictions and of the resulting value of $\alpha_s(m_Z)$ at the Z-boson mass m Z are studied as a function of...
Exclusive production of four charged pions at the ep collider HERA is studied at small photon virtualities $Q^2<2$ GeV${}^2$. The data were taken with the H1 detector in the years 2006 and 2007 at a centre-of-mass energy of $\sqrt{s}=319$ GeV and correspond to an integrated luminosity of 7.6 pb$^{-1}$. The cross section of the reaction $\gamma p \to 2(\pi^+\pi^-)Y$ is determined in the phase...
Measurements of the cross sections of the production of pairs of electroweak gauge bosons at the LHC constitute stringent tests of the electroweak sector of the Standard Model and provide a model-independent means to search for new physics at the TeV scale. The ATLAS collaboration has performed detailed measurements of integrated and differential cross sections of the production of heavy...
The newly proposed Electron-Ion Collider (EIC) with its unique capability to collide polarized electrons with polarized protons and light ions at unprecedented luminosity, and with almost all elements of heavy nuclei at high energy, will be the ideal and much needed facility to explore the emerging science of nuclear femtography, and take us to the next frontier of the Standard Model of...
The STAR Collaboration at RHIC is exploring the partonic origin of the proton spin with a broad range of measurements in polarized pp collisions. STAR measurements of the transverse single-spin asymmetry, A_N, for W boson production provide the first experimental investigation of the non-universality of the Sivers function. Precise follow-up measurements of A_N for direct photon production,...
Precision measurements of CP violating observables in the decays of b and c hadrons are powerful probes to search for physics beyond the Standard Model.
The most recent results on CP violation in the decay, mixing and interference of both b and c hadrons obtained by the LHCb Collaboration with Run I and years 2015-2016 of Run II are reviewed. In particular world best constraints and world...
The concept of lepton universality, where the muon and tau particles are simply heavier copies of the electron, is a key prediction in the Standard Model (SM). In models beyond the SM, lepton universality can be naturally violated with new physics particles that couple preferentially to the second and third generation leptons. Over the last few years, several hints of lepton universality...
An improved determination of electroweak (EW) parameters using H1 inclusive neutral current and charged current DIS cross sections is presented. The analysis benefits from the usage of the previously published cross sections using longitudinally polarised lepton beams. The parameters are determined in a combined fit of EW parameters together with PDFs. The predictions include NNLO QCD...
We study quantitatively [1] the importance of the recently derived NLO corrections [2,3,4] to the DIS structure functions at small x in the dipole formalism. We show that these corrections can be significant and depend on the factorization scheme used to resum large logarithms of energy into renormalization group evolution with the BK equation. This feature is similar to what has recently...
We present predictions for diboson production (with exact decays) that are next-to-next-to-leading order (NNLO) accurate and consistently matched to a parton shower (NNLOPS). The matching is achieved by upgrading the NLO WW+j calculation with MiNLO, in such a way that NLO accuracy is guaranteed for W+W- inclusive observables and by then performing a reweighting of the WWJ-MiNLO events,...
COMPASS is a fixed target experiment located at the M2 beamline of the SPS accelerator at CERN. One of the most important objectives of the experiment is the study of the spin structure of the nucleon. Within the QCD parton model approach, the quark structure of the nucleon spin can be parametrized in terms of quark transverse momentum dependent (TMD) parton distribution functions (PDFs) while...
In the HHT QCD fit the standard DGLAP evolution was augmented by including an additional low-x higher-twist term in the description of the longitudinal structure function, F$_\rm{L}$. This additional term significantly improves the description of the HERA reduced cross sections at low Bjorken-x and low four-momentum-transfer squared, Q$^2$. Since the HHT fit describes well data from the...
The angular analysis of the decay of Bd -> K* mu mu for a number of angular coefficients are measured as a function of the invariant mass squared of the di-muon system for data collected at 8 TeV. Comparison is made to theoretical predictions, including for the observable P’5, for which there has been recent tension between theory and experiment. In addition the study of kinematical...
Based on current CERN infrastructure, an electron--proton collider is proposed at a center-of-mass energy of about 9 TeV. A 7 TeV LHC bunch is used as the proton driver to create a plasma wakefield which then accelerates electrons to 3 TeV, these then colliding with the other 7 TeV LHC proton beam. Although of very high energy, the collider has a modest projected integrated luminosity of...
Measurements of the cross sections of the production of three electroweak gauge bosons and of vector-boson scattering processes at the LHC constitute stringent tests of the electroweak sector of the Standard Model and provide a model-independent means to search for new physics at the TeV scale. The ATLAS collaboration searched for the production of three W bosons or of a W boson and a photon...
We report on a first NLO computation of inclusive photon production at small x in
e+A collisions. The computation is performed to next-to-leading-log x accuracy and resums all multiple scattering (higher twist) computations within the CGC effective theory. In the soft photon (Low) limit, we recover results the NLO results of Balitsky and Chirilli for inclusive DIS. We point to key technical...
In this contribution we investigate the transverse single spin asymmetry in the inelastic $J/\Psi$ photoproduction in $p^\uparrow p$ and $p^\uparrow A$ collisions at RHIC energies. At leading order this process probes the gluon Sivers function. We predict large values for the cross sections, which indicates that its experimental analysis is, in principle, feasible. The rapidity dependence of...
The production of multi-jet final states at hadron colliders probes pQCD at several mass scales. The processes can also be used to probe the gluon density function of the proton. The ATLAS collaboration has used multi-jets events, recorded at a center of mass energy of 8 TeV, to measure the transverse energy-energy correlations, its asymmetry and the dijet azimuthal decorrelation. These...
Electroweak penguin B decays proceed through one loop diagrams at the lowest order. Since new particles beyond the Standard Model can enter in the loop, these processes are very sensitive to new physics. We report measurements of b → sl+l- decays at Belle. We also report other rare B decays sensitive to New Physics. The analyses are based on the full data set at Y(4S) and Y(5S) resonances at Belle.
The most recent results on the production of single W and Z bosons with two jets at high invariant mass at centre-of-mass energies of 7, 8 and 13 TeV are presented. Integrated and differential cross sections are measured in many different phase space regions with varying degree of sensitivity to the electroweak production in vector boson fusion. The cross section for the electroweak W boson...
Pions and kaons are, along with protons and neutrons, the main building blocks of nuclear matter. The distribution of the fundamental constituents, the quarks and gluons, is expected to be different in pions, kaons, and nucleons. However, experimental data are sparse. As a result, there has been persistent doubt about the behavior of the pion's valence quark structure function at large...
First we perform a phenomenological analysis of the cos 2φ azimuthal asymmetry in virtual photon plus jet production induced by the linear polarization of gluons in unpolarized pA collisions. Employing a small-x model input distribution, the asymmetry is found to be strongly suppressed under TMD evolution, but still remains sufficiently large to be measurable in the typical kinematical region...
A photon is a fundamental particle, instead of a nonperturbative composite like hadrons. However, an energetic photon can fluctuate into vector mesons in the kinematic region with a small Bjorken variable $x < 0.1$. Particularly at $x < 0.01$, the hadronic contribution to cross sections of the electron-photon deep inelastic scattering dominates, and a photon can be regarded as a hadron rather...
IceCube is a 1 cubic kilometer size neutrino detector located at the South Pole. It is capable of detecting all-sky neutrinos of all flavors from GeV to EeV energies. After detector completion, it discovered and measured the flux of extraterrestrial neutrinos in the TeV - PeV energy range, alongside with flux of neutrinos of known atmospheric origin. In this talk we will present a novel...
The production of massive vector boson pairs is a key process for the understanding of the non-abelian gauge structure of the standard model and for the comprehension of the electroweak symmetry breaking mechanism. In this presentation, we will report the most recent inclusive and differential measurements of multiboson production with data collected by the CMS. The recent study of the...
The talk will present the complete twist-4 result for the semi-inclusive deeply inelastic scattering $e^- N \to e^-qX$ with polarized electron and proton beams at the tree level of pQCD. The calculations have been carried out using the formulism obtained after collinear expansion where the multiple gluon scattering are taken into account and gauge links are obtained automatically in a...
We review the physics opportunities [1] which are offered by a next generation and multi-purpose fixed-target experiment exploiting the LHC beams in order to study $pp$, $pd$ and $pA$ collisions at $\sqrt{s_{NN}} \sim 115$ GeV as well as Pb$p$ and Pb$A$ collisions at $\sqrt{s_{NN}} \sim 72$ GeV.
We propose two possible implementations, namely with an internal (polarised) gas target or with a...
Calculations for dijet production in diffractive deep-inelastic scattering (DIS) at next-to-next-to-leading order accuracy (NNLO) are presented. The calculations are based on the antenna subtraction formalism and the hard coefficients are convoluted with currently available PDFs for diffractive scattering (DPDFs).
The NNLO predictions are compared to a large number of available measurements...
In this talk I will summarize the current design status of eRHIC with special emphasis on the integration of the EIC Physics requirements into the accelerator design.
The production of prompt isolated photons at hadron colliders provides a stringent test of perturbative QCD and can be used to probe the gluon density function of the proton. The ATLAS collaboration has performed precise measurements of the inclusive production of isolated prompt photons at a center-of-mass energy of 13 TeV, differential in both rapidity and the photon transverse momentum. In...
In this talk, I will discuss the relevance of using quarkonium-hadroproduction data in order to study the gluon TMDs in unpolarised protons. I will discuss the case of single $\eta_c$ production as well as that of $J/\psi(\Upsilon)+\gamma$ and $J/\psi$ pairs. In particular, I will discuss our first extraction of $f_1^g$ using the di-$J/\psi$ LHCb data and argue that $h_1^{\perp g}$ can be...
Recent results on associated top Higgs production at CMS are reviewed.
In ultra-peripheral heavy-ion collisions the ions encounter with such a large impact parameter that no strong interaction can take place. However, the photons produced by the colliding ion can interact either with the other nucleus or with a photon from the another nucleus. The former corresponds to photoproduction studied earlier in electron-proton collisions at HERA but with a nuclear...
Measurements of single top-quark production in proton-proton collisions are presented based on the 8 TeV and 13 TeV ATLAS datasets. In the leading order process, a W boson is exchanged in the t-channel. The cross-section for the production of single top-quarks and single anti-top-quarks, their ratio, as well as differential cross-section measurements are also reported. These analyses include...
An Electron Ion Collider (EIC) has been identified in the Nuclear Physics Long Range Plan as the highest-priority facility for new construction. This talk presents an overview and status of the Jefferson Lab design of an EIC (JLEIC). It features frequent collisions of small electron and ion bunches providing a luminosity of $10^{33}$-$10^{34}$ cm$^{-1}$s$^{-1}$ in a broad range of the...
The search for the production of the Higgs Boson with a pair of top-anti-top quarks is both very important and very challenging. This talks presents the analyses using Higgs boson decays to bbbar pairs, to two Z bosons, to other multi-lepton final states, and to a pair of photons, using 36 fb-1 of pp collision data collected at 13 TeV, as well as their combined results.
A comprehensive set of measurements of top quark pair and single top quark production in association with EWK bosons (W, Z or ɣ) is presented. The results are compared to theory predictions and re-interpreted as searches for new physics inducing deviations from the standard model predictions using an effective field theory approach. The status of the search for four top quark production, to...
Albeit initially designed for b-physics, LHCb has demonstrated to function very well as a general-purpose forward detector, covering the pseudo-rapidity range 2 < eta < 5.
Several measurements concerning the production of W, Z and top have been performed using LHCb data. A selection of relevant results will be presented, highlighting LHCb's new measurement of tt production at \sqrt{s}=13 TeV.
The first measurement of transverse-spin-dependent azimuthal
asymmetries in the pion-induced Drell-Yan (DY) process will be
presented, which was reported in PRL 119, 112002. We use the CERN SPS
190 GeV/c pi- beam and a transversely polarized ammonia target.
Three azimuthal asymmetries giving access to different
transverse-momentum-dependent (TMD) parton distribution functions
(PDFs) are...
Muon reconstruction and identification play a fundamental role in many analyses of central importance in the LHC run-2 Physics pro- gramme. The algorithms and the criteria used in ATLAS for the re- construction and identification of muons with transverse momentum from a few GeV to the TeV scale will be presented. Their performance is measured in data based on the decays of Z and J/ψ to pair of...
In this talk I will present an overview of the
scientific opportunities that would be addressed by the Electron-Ion-Collider
in China (EicC).
The polarized EicC will open up a new window to study
the one and three dimensions (3D) nucleon structure for both sea and valence
quarks and help fully understand the strong interaction.
In the first phase the EicC will be 3~ 5 GeV polarized
electron...
Measurements of the Drell-Yan production of W and Z/gamma bosons at the LHC provide a benchmark of our understanding of perturbative QCD and probe the proton structure in a unique way. The ATLAS collaboration has performed high precision measurements at center-of-mass energies of 7 and 8 TeV. The measurements are performed for W+, W- and Z/gamma bosons integrated and as a function of the...
The large centre-of-mass energy available at the proton-proton collider LHC allows for the copious production of top quark pairs in association with other final state particles at high transverse momenta. The ATLAS experiment has measured several final state observables that are sensitive to additional radiation in top anti-top quark final states. Results on the top production in association...
Measurements of $t\bar{t}H$ production in the $H \to b\bar{b}$ channel depend in a critical way on the theoretical uncertainty associated with the irreducible $t\bar{t}+b$-jet background. In this paper, analysing the various topologies that account for b-jet production in association with a $t\bar{t}$ pair, we demonstrate that the process at hand is largely driven by final-state $g \to...
Isolated photons with high transverse energy have been studied in
deep inelastic $ep$ scattering with the ZEUS detector at HERA, using
an integrated luminosity of $326\, \mathrm{pb}^{-1}$ in the range of
exchanged-photon virtuality $10 - 350 \,\, \mathrm{GeV}^2$. Outgoing
isolated photons with transverse energy $4< E_T^\gamma< 15$ GeV and
pseudorapidity $-0.7 < \eta^\gamma < 0.9$ were measured...
Transverse single-spin asymmetries (TSSA) of light hadron production from $p^{\uparrow}+p$ collisions provide valuable information on the spin structure of the nucleon. TSSA in the process $p^\uparrow + p \rightarrow h+X$ has been described in terms of twist-3 spin-dependent three-parton correlation functions, or twist-3 fragmentation functions in the QCD collinear factorization approach. In...
We report on a detector concept, TOPSiDE, being developed for the EIC
Electron-Ion Collider. TOPSiDE aims a the detection and identification
of all particles created in electron-proton/ion collisions at the EIC
while achieving the best possible momentum/energy resolution. The
measurement of hadronic jets exploits the advantages offered by Particle
Flow Algorithms (PFAs), which in turn require...
The production of prompt photons in association with jets in proton–proton collisions provides a testing ground for perturbative QCD (pQCD) with a hard colourless probe less affected by hadronisation effects than jet production. The measurements of the angular correlations between the photon and the jets can be used to probe the dynamics of the hard-scattering process. We present here a...
Precise measurements of the properties of the top quark test the Standard Model (SM) and can be used to constrain new physics models. As it may be significantly enhanced by the presence of new physics, the ttbar production charge asymmetry is measured inclusively and differentially using the 8 TeV ATLAS dataset using both the lepton+jets and dilepton channels, including a dedicated measurement...
We study the orbital angular momentum (OAM) of quarks and gluons in the nucleon in the small-x region. We argue, in two different ways, that the gluon OAM significantly cancels the gluon helicity distribution at small-x. A similar cancellation occurs also in the quark sector.
We report a measurement of the cross section for K^0_S pair production in single-tag two-photon collisions, gamma gamma → K^0_S K^0_S for Q^2 up to 30 GeV^2, where Q^2 is the negative of the invariant mass squared of the tagged photon. The measurement covers the kinematic range 1.0 GeV < W < 2.6 GeV and |cos theta|<1.0 for the total energy and kaon scattering angle, respectively, in the...
The proposed sPHENIX detector at the Relativistic Heavy Ion Collider (RHIC), together with RHIC’s unique capabilities to collide polarized protons and heavy nuclei, will open the door to exciting new measurements to enhance our understanding of quantum chromodynamics (QCD). These measurements will reveal more about how partons behave in a nuclear environment, explore spin-spin and...
In a recent article (1801.06113), we discussed the possibility of using simple matrix elements to produce probabilities of rearranging the colour chains in dipole shower algorithms. Due to the changed density of larger and smaller dipole chains, particle spectra and standard observables are modified. In the talk, I will discuss the idea and the consequences for tuning and the soft model of...
A correct modelling of the underlying event in proton-proton collisions is important for the proper simulation of kinematic distributions of high-energy collisions. The ATLAS collaboration extended previous studies at 7 TeV with a leading track or jet or Z boson by a new study at 13 TeV, measuring the number and transverse-momentum sum of charged particles as a function of pseudorapidity and...
Results of the QCD analysis of a variety of the
hard-scattering data is over-viewed with a particular
focus on determination of the quark distributions in the nucleon.
A potential of the recent precise data collected at the LHC
for the problem of quark species disentangling is discussed and
compared to the impact of the low-energy fixed-target data
Finally, remaining challenges and...
The STAR experiment is planning to upgrade the forward rapidity region (2.5 < eta < 4.5) to enable novel measurements in p+p, p+A and A+A collisions. The upgrade is motivated by exploration of cold QCD physics in the very high and low regions of Bjorken x. The current design envisions a Calorimeter System (FCS) that integrates parts of the refurbished PHENIX sampling ECal and a hadronic...
Measurements of the inclusive and differential top-quark pair cross sections in proton-proton collisions at both 8 and 13 TeV with the ATLAS detector at the Large Hadron Collider are presented. The inclusive measurements reach high precision and are compared to the best available theoretical calculations. Differential measurements of the kinematic properties of the top quark production are...
In this work we will present predictions for top-quark pair differential distributions at the LHC13 at NNLO QCD accuracy and including EW corrections. For the latter we include not only contributions of ${\mathcal O}(\alpha_s^2 \alpha)$, but also those of order ${\mathcal O}(\alpha_s \alpha^2)$ and ${\mathcal O}( \alpha^3)$. We will discuss the difference between the additive and...
We discuss the most recent updates to the PDFs obtained in the MMHT framework.
We study of the impact of the most recent LHC data and in particular focus on issues in finding good fits to these data given the very high precision now
available and the implications for PDFs and their uncertainties.
We present results on the measurement of the underlying event at 13 TeV and recent results from Minimum Bias measurements with the CMS experiment.
Over the years many different types of fits for the strong coupling constant have been performed. However one high precision result that currently significantly differs from the world average are results from event shapes at electron positron colliders. One possible source for the difference in these results could be the degeneracy between the fit of the strong coupling constant and...
The quark-gluon dynamics manifests itself in a set of non-perturbative functions describing all possible spin-spin and spin-orbit correlations. The Transverse Momentum Dependent parton distributions (TMDs) and Generalized Parton Distributions (GPDs) carry information not only on the longitudinal but also on the transverse momentum and position of partons, providing rich and direct information...
We present the recent progress on parton distribution functions (PDF) of the proton from the CTEQ-TEA collaboration.
Differential measurements of top quark pair and single top quark (t-channel) production cross sections are presented using data collected by CMS at different centre-of-mass energies. The cross sections are measured as a function of various kinematic observables of the top quarks and the jets and leptons of the event final state. The ttbar measurements are extended to the TeV range using jet...
New CMS PYTHIA 8 event tunes are presented. The new tunes are obtained using minimum bias and underlying event observables using Monte Carlo configurations with consistent parton distribution functions and strong coupling constant values in the matrix element and the parton shower. Validation and performance studies are presented by comparing the predictions of the new tune to various soft-...
Calculations of jet substructure observables which are accurate beyondleading-logarithmic accuracy have recently become available. Such observables are significant not only for probing a new regime of QCD at a hadron collider, but also for improving the understanding of jet substructure properties that are used in many studies at the Large Hadron Collider. In this talk, we discuss first...
We present an upgrade of the venerable FONLL code to handle top quark production. Predictions for large transverse momentum distributions at NLO+NLL accuracy are presented. Comparisons to recent experimental data, and to NNLO fixed order predictions and to SCET resummations, as well as to Monte Carlos matched to NLO predictions, are performed. Phenomenological relevance of the large transverse...
We present a new set of parton distributions, NNPDF3.1, which updates NNPDF3.0, the first global set of PDFs determined using a methodology validated by a closure test. The update is motivated by recent progress in methodology and available data, and involves both. On the methodological side, we now parametrize and determine the charm PDF alongside the light quarks and gluon ones, thereby...
As a part of the general nucleon imaging effort, there have been many efforts to access the transverse momentum dependent parton distributions (TMDs) by using the semi-inclusive deep inelastic scatterings (SIDIS) processes. The recently upgraded Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) provides golden opportunities to study them in valence quark region. The...
In order to exploit the abundance of high momentum heavy particles produced at LHC (top, W/Z and Higgs) and decaying hadronically, the study of jet substucture has become increasingly important throughout a wide array of searches and measurements. The latest ATLAS results in terms of jet substructure measurements and calibrations are presented including studies of performance sensitivity to...
Inclusive four-jet events produced in proton--proton collisions at a center-of-mass energy of 7 TeV have been analyzed for the presence of hard double parton scattering collected with the ATLAS detector. The contribution of hard double parton scattering to the production of four-jet events has been extracted using an artificial neural network. The assumption made was that hard double parton...
In this talk we introduce a newly developed scheme based on an extension of the 5F flavour scheme, which treats $b$ quarks as massless partons, to include full heavy quark mass dependency. We name this extension five-flavour massive scheme. We implement this scheme at MC@NLO accuracy in Sherpa. We present some results, obtained in this scheme, for $b$ quarks produced in association with a...
In the present paper, the ATLAS inclusive $W^{\pm}$ and $Z$ boson production data are analysed together with the CMS inclusive $W^{\pm}$ and $Z$ boson production data to investigate any possible tensions between the data sets and to determine the strange sea fraction, within the framework of a parton distribution function fit at next-to next-to leading order in perturbative QCD.
We present results on measurements of characteristics of events with jets, from jet-charge over investigations of shapes to jet mass distributions, and angular correlations in multi-jet events. The measurements are compared to theoretical predictions including those matched to parton shower and hadronization.
In this work, we present a systematic study on the feasibility of probing the largely unexplored gluon Sivers function (GSF) based on the open charm production, charged dihadron and dijet method at a future high energy, high luminosity Electron-Ion Collider (EIC). Sivers function describes the anisotropy of parton distributions inside a transversely polarized nucleon in the momentum space and...
We present recent results on Double Parton Scattering (DPS) studies using data collected during Run 1 and Run 2 of the LHC with the CMS experiment. Double parton scattering is investigated in several final states including vector bosons and multi-jets. Measurements of observables designed to highlight the DPS contribution are shown and compared to MC predictions from models based on multiple...
The sensitivity of CMS measurements to Parton Distribution Functions, strong coupling constant and treatment of heavy flavours in QCD analyses is presented. CMS data collected at various center-of-mass energies and their impact on the PDFs are presented. Measurements of cross sections of jet and to-quark pair production are in particular sensitive to the gluon distribution in the proton and...
This panel discussion will be chaired and moderated by Aharon Levy.
For more detail, see https://indico.cern.ch/event/656250/page/13094-discussion-for-a-document-for-european-strategy-update
More questions and discussions from the audience and remote participants.
We present recent results on forward energy flow and forward jet production measurements in CMS, including measurements with proton-proton collisions at 13 TeV, and proton-lead collisions at 5 TeV.
Results on Higgs differential cross-sections measurements at CMS are reviewed.
The production of jets and electroweak gauge bosons in association with a jet, V+jet, constitute two important classes of standard-candle processes at the LHC. Owing to the large event rate and the direct sensitivity to the strong coupling constant and the gluon PDF, they provide an ideal testing ground for our understanding of perturbative QCD in a hadron-collider environment.
I give an...
The polarized electron accelerator at Jefferson Laboratory (JLab) in Newport News, Virginia, USA yields a robust program for the study of the spin physics of the nucleon. The CLAS detector and longitudinally polarized target in Hall-B at JLab were employed in multiple measurements of spin-structure functions for the proton and neutron in the resonance and DIS regions at beam energies of up to...
A high-energy high-luminosity polarized Electron Ion Collider (EIC) was enthusiastically recommended
by the US nuclear science advisory committee (NSAC), as the highest priority new facility
to be built in the US, in its long range planning exercise conducted in 2015. Understanding the role
played by the gluons in binding quarks and gluons in nucleons and nuclei — most of the visible
universe...
Measurements and searches of Higgs boson decays to two third- or two second-generation quarks or leptons are presented using 36 fb-1 of pp collision data collected at 13 TeV.
We improve the state-of-the-art description of the disappearance of the away-side peak in forward pA collisions at Relativistic Heavy Ion Collider (RHIC) energies in the framework of the Color Glass Condensate (CGC).
Using the recently proposed improved transverse momentum dependent (ITMD) factorization formula for two-particle production in the back-to-back limit, we derive a parameter-free...
The STAR experiment at the Relativistic Heavy-Ion Collider at Brookhaven National
Laboratory is carrying out a spin physics program in high-energy polarized proton collisions
to gain a deeper insight into the spin structure and
dynamics of the proton.
The collision of polarized protons at $\sqrt{s}=510\,$GeV opens a new era of spin-flavor
structure measurements from $W^{+}/W^{-}$ boson...
In electron-proton collisions, the incoming electron is coupled directly to a parton of the proton with the exchange of a virtual photon, which has properties close to a real photon when the transfer momentum is small. In QCD, the exchanged physical photon can be approximated as a superposition of the bare photon state (direct process) and the hadronic photon state (resolved process). We...
A detailed mapping of the dominant kinematical domains contributing to the prompt atmospheric neutrino flux at high neutrino energies is presented by studying their sensitivity to the cuts on several kinematical variables crucial for charm production in cosmic ray scattering in the atmosphere. This includes the maximal center-of-mass energy for proton-proton scattering, the longitudinal...
We present the first threshold and jet radius jointly resummed cross section for single-inclusive hadronic jet production. We work at next-to-leading logarithmic accuracy and our framework allows for a systematic extension beyond the currently achieved precision. Longstanding numerical issues are overcome by performing the resummation directly in momentum space within Soft Collinear Effective...
Measurements of Higgs boson properties and cross sections measured in Higgs boson decays to two photons, two Z bosons, and two W bosons based on pp collision data collected at 13 TeV are presented. In addition, results from the combination of different decay channels are shown.
Exclusive vector meson electroproduction over a broad $Q^2$ range offers a unique opportunity to probe the gluon structure of nuclei to measure nuclear shadowing, and to search for gluon saturation and/or the colored glass condensate at an Electron-Ion Collider. Understanding the kinematic distributions and cross sections for specific processes can impact detector design to maximize their...
Using the formalism of the light-cone wave function in perturbative QCD together with the hybrid factorization, we compute the cross-section for three particle production at forward rapidities in proton-nucleus collisions. In this picture, the three produced partons — a quark accompanied by a gluon pair, or two quarks plus one antiquark — are all generated via two successive splittings of a...
We report on recent studies of quarkonium decays obtained with the data collected by the BaBar experiment at the PEP-II $e^+e^-$ collider.
In particular, we use the entire BaBar dataset to study the reaction $e^+ e^- \to \gamma_{ISR} J/\psi$, with $J/\psi \to \pi^+ \pi^- \pi^0$, $J/\psi \to K^+ K^- \pi^0$, or $J/\psi \to K_S K^\pm \pi^\mp$, and the photon $\gamma_{ISR}$ produced via...
The W measurement at RHIC (Relativistic Heavy Ion Collider) provides unique access to the sea quark polarization of the proton. By measuring decay leptons from parity-violating W bosons, which only coupled to left-handed quarks and right-handed antiquarks, a clean, fragmentation free measurement is possible in addition to natural flavor separation. In this talk, we present status and...
We present measurements of differential jet cross sections over a wide range in transverse momenta from inclusive jets to multi-jet final states. Studies on the impact that these measurements have on the determination of the strong coupling alpha_s as well as on parton density functions are reported.
Observation of Higgs in tautau is reported, together with results from Higgs in bb and mumu decays.
A new analysis of published experimental data from the HERMES experiment has been performed. This analysis extracts new information on the space-time properties of color propagation through fitting to a geometric model of the interaction with a realistic nuclear density distribution. Our approach uses a simultaneous fit to the transverse momentum broadening observable and the hadronic...
We present the first extraction of the transversity distribution in the framework of collinear factorization based on the global analysis of pion-pair production in deep-inelastic scattering off transversely polarized targets and in proton-proton collisions with one transversely polarized proton. The extraction relies on the knowledge of dihadron fragmentation functions, which are taken from...
The production process of quarkonia in proton-proton (pp) collision is a very good probe of the parton structure of the proton.
Recent experimental data of the production of $J/\psi$+vector boson or quarkonium pairs at the LHC and Tevatron suggest the relevance of double parton scattering (DPS).
In this talk, we will discuss the single parton scattering (SPS) contribution of the $J/\psi+Z$,...
We calculate the transverse momentum dependent gluon-to-gluon splitting function within kT-factorization, generalizing the framework employed in the calculation of the quark splitting functions in [1205.1759, 1511.08439, 1607.01507] and demonstrate at the same time the consistency of the extended formalism with previous results. While existing versions of kT factorized evolution equations...
Measurement of the properties of the Higgs boson, especially in the gamma-gamma and ZZ channels, are reported.
DIS on the deuteron with detection of a proton in the nuclear fragmentation region ("spectator tagging") represents a unique method for extracting the neutron structure functions and their spin dependence. The measured proton recoil momentum (~ few 100 MeV in the deuteron rest frame) controls the nuclear configuration during the DIS process and allows one to eliminate nuclear binding effects...
The production of inclusive jets and di-jets at hadron colliders provides a stringent test of perturbative QCD at the highest energies. The process can also be used to probe the gluon density function of the proton. The ATLAS collaboration has measured the inclusive jet production cross section in 20.3 /fb of data collected at a center-of-mass energy of 8TeV and in 3.2 /fb of data collected at...
The largest data sample accumulated by the Belle experiment at KEKB asymmetric energy e+e- collider provides an opportunity to perform studies of charmed hadrons. In this presentation, we report on the studies of the decay modes of Lambda_c, Omega_c and spectroscopy of excited Omega_c and Xi_c. The studies presented here use the full data accumulated by the Belle experiment.
We discuss the first attempt at a "global fit" of unpolarized Transverse Momentum Distributions, using data from semi-inclusive deep inelastic scattering and Drell-Yan processes. We describe the main features of this extraction, compare its outcome with new data, and discuss what further developments are needed.
We discuss the \gamma \to \rho^0 impact factor, i.e., the transition amplitude of a photon to a neutral vector meson \rho^0, where the transition is mediated by the two t-channel gluons. The impact factor is a building block in the QCD descriptions of high-energy exclusive processes like $\gamma p \to V p$, and $\gamma\gamma \to V V$, with $V = \rho^0, \omega, \phi$, …. In the framework of QCD...
Theories beyond the Standard Model predict Higgs boson decays at a much enhanced rate compared to the Standard Model, e.g. for decays to Z+photon or a meson and a photon, or decays that do not exist in the Standard Model, such as decays into two light bosons (a). This talk presents recent results based on 36 fb-1 of pp collision data collected at 13 TeV.
Heavy flavor production in DIS (open charm, beauty) provides a direct probe of the gluon density in the target. It can be used to determine the unknown nuclear modifications of the gluon density at large x (EMC effect, antishadowing), which reveal the fundamental QCD substructure of nucleon interactions in the nucleus. We report about a study of open charm production in nuclear DIS at a future...
The Electron-Ion Collider (EIC) is the next-generation U.S.-based facility to study Quantum Chromodynamics by probing the dynamics of gluons and sea quarks with comprehensive and systematic measurements of high precision. The experimental program of the EIC is, thus, diverse, covering a broad range of studies from mapping the spatial, momentum, spin, and flavor distributions of gluons and sea...
We use for the first time experimental data for the inclusive heavy quark (D0, J/Psi, B->J/Psi and Y(1S) mesons) production in proton-lead collisions at the LHC in order to improve our knowledge of the gluon momentum distribution inside heavy nuclei. We observe that the nuclear effects encoded in both most recent global fits of nuclear parton densities at next-to-leading order (nCTEQ15 and...
The production of jets in association with vector bosons is an important process to study QCD in a multi-scale environment. The ATLAS collaboration has performed measurements of vector boson+jets cross sections, differential in several kinematic variables, in proton-proton collision data taken at center-of-mass energies of 8TeV and 13TeV. The measurements are compared to state-of-the art...
Quarkonium production at LHC energies proceeds mainly via gluon fusion on relatively short timescales. The measurement of quarkonium cross sections and kinematical distributions in pp collisions allows one to test available production models. The measurement of such observables in p-Pb collisions provides access to the nuclear modifications of parton distribution functions and to other...
The STAR experiment has been studying the spin structure of the proton, using the unique high-energy polarized proton collider, the Relativistic Heavy Ion Collider (RHIC). The kinematic coverage at STAR allows accessing gluons because quark-gluon and gluon-gluon scatterings dominate particle production at low and medium transverse momentum. The polarized gluon distribution function can be...
Many models of physics beyond the Standard Model (SM) introduce enhanced couplings to third generation quarks. The predicted signatures at the LHC include single and pair production of vector-like quarks and heavy resonances decaying to third generation quarks. We present results from searches obtained with the full 2016 dataset of proton-proton collisions at 13 TeV. A wide range of final...
As evinced by multiple astrophysical measurements, a large fraction of the matter in the Universe is in the form of a dark, non-baryonic component. If dark matter interacts weakly with the Standard Model it could be produced at the LHC, escaping the detector and thus leaving a signature of large missing transverse momentum. A broad and systematic search program for dark matter production in...
We use nCTEQ15 nPDFs with uncertainties to identify measurements which
have a potential impact on nuclear corrections and flavor
differentiation. In particular, recent LHC W/Z vector boson production
data in proton-lead and lead-lead collisions are quite sensitive to
heavier flavors (especially the strange PDF). This complements the
information from neutrino-DIS data. As the proton flavor...
The largest data sample accumulated by the Belle experiment at KEKB asymmetric energy e+e- collider provides an opportunity to perform studies of bottomonia. We report on the study of bottomonium production in association with an eta meson in e+ e- annihilations near Y(5S), and the measurement of e+ e^ → chi_bJ phi, chi_bJ omega near Y(6S). We also present the measurement of the decays Y(4S) →...
The production of vector bosons (W, Z, gamma) in association with jets is a stringent test of perturbative QCD and is a background process in searches for new physics. Total and differential cross-section measurements of vector bosons produced in association with jets in proton-proton collisions performed by the CMS collaboration at the LHC are presented. The measurements are compared to the...
Jet production in high energy proton-proton ($pp$) collisions is dominated by hard QCD scatterings such as gluon-gluon ($gg$) and quark-gluon ($qg$) scatterings, and therefore an effective tool to probe the internal distribution of gluons in the proton. The STAR Collaboration at Relativistic Heavy Ion Collider (RHIC) is using longitudinally polarized $pp$ collisions at center of mass energies,...
In this talk I will discuss the challenges to measure hadron polarization in high collision frequency and luminosity future electron ion colliders.
Results from double Higgs production with the CMS experiment are reviewed.
We discuss the implications of the (preliminary) CMS dijet data from 5.02 TeV pp and pPb collisions for gluon PDFs of the proton and nuclei. The preliminary pp data show a discrepancy with NLO predictions using CT14 and MMHT14 PDFs. We find that this difference cannot be accommodated with the associated scale uncertainties and debate the possible changes needed in the gluon PDFs. A similar...
The charmonium spectroscopy is studied from lattice QCD. An extensive set of excited states as well as the states with exotic quantum numbers are obtained. In this talk, I present and discuss the results in light of experimental observations. In particular, I will discuss the lightest hybrid meson supermultiplet that is identified in our results. Additionally, I will present a preliminary...
Geometry tagging is an experimental analysis technique for selecting event samples where we can, on a statistical basis, control the geometry of the collision in order to make more incisive physics measurements. This technique has been heavily exploited in heavy ion (AA) collisions at RHIC and the LHC, and played an essential role in the discovery and detailed characterization of the quark...
I will present the current status of the determination of the QCD coupling $\alpha_s$ from the 15 methods where high-precision theoretical calculations and experimental measurements are (or will be) available including, among others: (i) lattice QCD, (ii) $\tau$ hadronic decays, (iii) soft parton-to-hadron fragmentation functions, (iv) proton structure functions, (v) e+e- event shapes and jet...
The longitudinal double-spin asymmetry $A_{LL}$ in spin-polarized $p+p$ collisions provides insight into the gluon contribution to the proton's spin by accessing the gluon helicity distribution $\Delta$g. Prior RHIC 200 GeV measurements show non-zero asymmetries and hence indicate a nonzero contribution of gluon helicity to the proton spin $\Delta$G for the Bjorken-$x$ range $x > 0.05$ in the...
The Belle II experiment, about to start taking data at the KEK laboratory in Japan, is a substantial upgrade of both the Belle detector and the KEKB accelerator.
It aims to collect 50 times more data than existing B-Factory samples beginning in early April 2018.
Belle II is uniquely capable to study the so-called "XYZ" particles: heavy exotic hadrons consisting of more than three quarks....
SeaQuest at FNAL is a fixed-target experiment to measure the Drell-Yan process in $p+p$ and $p+A$, using the 120-GeV proton beam and targets of liquid hydrogen, liquid deuterium, carbon, iron and tungsten. During the course of operations, completed in July 2017, it recorded data from $1.4\times 10^{18}$ protons on the various targets.
SeaQuest aims at precisely measuring the flavor asymmetry...
Searches for resonant and non-resonant Higgs boson pair production are performed with LHC data. The searches cover a wide mass range for the resonant case and different decay channels have been explored. No significant deviation from the Standard Model prediction is observed
in data. The 95% conference-level observed and expected limit is set on the cross-section for non-resonant/resonance production.
The recent PEPPo (Polarized Electrons for Polarized Positrons) experiment at the
Thomas Jefferson National Accelerator Facility did open an easy and low-cost access
to polarized positron beam through the efficient production of polarized positrons
from the bremsstralhung radiation of a MeV polarized electron beam. The application
of this technique in the context of the upgraded CEBAF...
Measurements of open beauty and charm production cross sections in deep inelastic ep scattering at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross sections for beauty and charm production are obtained in the kinematic range of photon virtuality $2.5\le Q^2 \le 2000$ GeV$^2$ and Bjorken scaling variable $3 \times 10^{−5}\le x_{Bj} \le 5 \times 10^{−2}$. The combination...
Energy-frontier DIS can be realised at CERN through an energy recovery linac that would produce 60 GeV electrons to collide with the HL-LHC or, eventually, with the HE-LHC or the FCC hadron beams. It would deliver lepton-proton/nucleus collisions with center of mass energies in the range 0.8-3.5 TeV per nucleon, and luminosities exceeding $10^{34}$ ($5\times 10^{32}$) cm$^{-2}$s$^{-1}$ in ep...
I will present a method for the computation of logarithmically
enhanced terms at all orders for observables featuring kinematic cancellations
away from the Sudakov limit. I will describe the approach in the context of observables of interest at colliders, and comment on extensions to more general cases.
Coherent photoproduction of vector mesons is sensitive to the shape of the target nucleus, as probed at Q^2 ~ (M_V/2)^2. Previously STAR presented a high-statistics measurement of d\sigma/dt for rho^0 photoproduction in ultra-peripheral Au+Au collisions, and made a two-dimensional Fourier-Bessel (Hanckel) transformation to give the distribution of targets in the nucleus. Here, we study the Q^2...
Recent results on the search for the rare and exotic decays of the Higgs boson H(125) from the CMS experiment will be presented in this talk. The large dataset delivered by LHC and collisions at higher center of mass energy of 13 TeV have significantly improved the search sensitivity for these rare and exotic decays with respect to Run-1.
A new collinear factorization analysis of inclusive DIS scattering with suitable non-perturbative “jet correlators” shows that a novel, non perturbative spin-flip term associated with the invariant mass of the produced hadrons couples to the target's transversity distribution function. In inclusive cross sections, this provides an hitherto neglected and large contribution to the twist-3...
Final states with isolated photons are expected in models of gauge mediated breaking of supersymmetry, but they can also occur as a result of decays of Higgs bosons produced in the decay chains of supersymmetric particles. Results of searches for strong and electroweak production of supersymmetry in events with one or two isolated photons are presented, based on pp collisions recorded with the...
The electromagnetic field of a fast moving lead ion at the LHC is an intense source of quasi-real photons. This makes it possible to study J/Psi exclusive photoproduction off protons in p-Pb collisions at the LHC. This process is sensitive to the gluon content of the target. Measuring the scattering angle of the produced vector meson one can compute the centre-of-mass energy (W) of the...
We study lepton-pair production in association with bottom quarks at the LHC,
and present the predictions obtained at next-to-leading order in QCD,
both at fixed order and matched with a QCD parton shower, for several differential distributions.
We discuss the estimate of the theoretical uncertainties
and consider the dependence on the perturbative QCD scales (renormalisation, factorisation...
We study the double-spin asymmetry $A^{\cos\phi_S}_{LT}$ in semi-inclusive DIS for charged and neutral pions production by scattering a longitudinal polarized beam off a transversely polarized proton target. Within the collinear framework, in which the transverse momentum of the final state hadron is integrated out, we predict the asymmetries for three pion productions at the kinematics of...
Constraints on parton distribution functions are presented that are based on differential cross-section measurements of single lepton and dilepton kinematic distributions in dileptonic top quark pair events. The measurements utilize 20.2 fb-1 of sqrt(s) = 8 TeV pp collisions recorded by the ATLAS experiment at the LHC. The sensitivity of the cross-sections to the gluon parton distribution...
Many supersymmetric scenarios feature final states with non-standard final state objects. The production of massive sparticles can lead to the production of boosted top quarks or vector bosons, high-pt b-jets. At the same time, transitions between nearly mass-degenerate sparticles can challenge the standard reconstruction because of the presence of very soft leptons or jets. The talk will...
Parton densities PDFs are most important objects both from a fundamental point of view, for characterising the partonic content of hadrons and nuclei, and for the application of collinear factorisation in hadronic and nuclear collisions. Nuclear PDFs are greatly unknown, compared to those in the proton, due to the scarcity of experimental data. In this talk I will first review the present...
We present recent results on the exclusive production of the Upsilon and rho mesons with the CMS experiment in proton-lead collisions at 5 TeV. And measurements of dipion production in proton-proton collisions at 5, 7, and 13 TeV.
The transverse spin transfer from polarized proton to $\Lambda$ and $\bar{\Lambda}$ hyperons is expected to be sensitive to the transversity distribution of the nucleon, and to the transversely polarized fragmentation function. We report the first measurement of the transverse spin transfer of $\Lambda$ and $\bar{\Lambda}$ along the polarization direction of the fragmenting quark, $D_{TT}$, in...
We present measurements of the total and differential cross-section of vector bosons produced with heavy flavor quarks (HF) and the impact of recent V+HF measurements performed by the CMS collaboration on the constraints of PDFs.
With the high integrated luminosities recorded at the LHC and the very good understanding of the ATLAS detector, it is possible to measure electroweak observables to the highest precision. In this talk, we review the measurement of the W boson mass using data, collected at 7 TeV. Special focus is drawn on a discussion of the modeling uncertainties and the physics potential of the latest low-mu...
R-parity violation introduces many viable signatures to the search for supersymmetry at the LHC. Strongly interacting resonances and lightest supersymmetric particles may decay into many leptons or jets with or without missing transverse momentum. Several supersymmetric models also predict massive long-lived supersymmetric particles. Such particles may be detected through abnormal specific...
The LHCb experiment allows to measure the production and polarisation of charm and beauty hadrons including quarkonia in various collision systems in collider and fixed-target mode. The forward rapidity acceptance in the laboratory frame and the covered Q^2 range test perturbative QCD calculations with their factorisation assumptions and put constraints on parton densities of in unique ...
Prospects for high precision determination of PDFs and alpha_s are presented, including results from HL-LHC, FCC, LHeC and EIC.
We investigate the spin-dependent (naive) T-odd fragmentation function $D^\perp_{1T}$, which can provide an explanation on the transverse polarization of the $\Lambda^0$ hyperon produced in an unpolarized process. We calculate $D^\perp_{1T}$ for light flavors in the spectator diquark model, with a Gaussian form factor at the hyperon-quark-diquark vertex. We include in the calculation both the...
In this contribution we present a comprehensive analysis of exclusive vector-meson photoproduction in $pp$, $pPb$ and $PbPb$ collisions at Run 2 LHC energies using the color dipole formalism. The rapidity distributions and total cross sections for the $\rho$, $\phi$, $J/\Psi$ and $\Upsilon$ production are estimated considering the more recent phenomenological models for the dipole-proton...
Many supersymmetry models feature gauginos and also sleptons with masses less than a few hundred GeV. These can give rise to direct pair production rates at the LHC that can be observed in the data sample recorded by the ATLAS detector. The talk presents results from searches for gaugino and slepton pair production in final states with leptons, and were performed with pp collisions at a...
State-of-the-art theoretical predictions accurate to next-to-leading order QCD interfaced with Pythia8, Herwig, and Sherpa event generators are tested by comparing the unfolded ttbar differential data collected with the CMS detector at 8 and 13 TeV. These predictions are also compared with the underlying event activity distributions in ttbar events using CMS proton-proton data collected at a...
We present calculation of next-to-next-to-leading order QCD corrections to massive charged-current coefficient functions in deep-inelastic scattering. Especially we focus on the application to charm-quark production in neutrino scattering on fixed target that can be measured via the dimuon final state.
The LHeC and the FCC-eh at CERN are projected machines that will deliver ep (ePb) collisions with center-of-mass energies in the TeV range and luminosities of order $10^{34}$ ($5 \times 10^{32}$) cm$^{−2}$s$^{−1}$. In this talk the possibilities for small-x physics and diffraction will be reviewed, with emphasis on recent results on the extraction of diffractive parton densities.
We present a model of coherent and incoherent photoproduction of vector mesons off proton and off nuclear targets. The computations are perfomed within the color-dipole formalism. The targets are described by a profile, in the impact parameter space, including subnucelon degrees of freedom, so-called hot spots. Their positions change event by event. The key aspect of our model is that the...
COMPASS at CERN, a facility designed to perform research in the hadron partonic structure and hadron spectroscopy, is now planning its future beyond 2020. After a brief summary of achieved results the presentation will focus on the COMPASS programme, planned between CERN accelerator long shutdowns 2 and 3: measurements of SSA using the muon beam on a transversely polarised deuteron target and...
Measurements of heavy-flavour production are a powerful tool to study the properties of the strongly-interacting partonic medium created in ultra-relativistic heavy-ion collisions. The measurements in pp collisions serve as a precision test of perturbative QCD apart from providing the crucial reference for Pb-Pb collisions. Measurements in p-Pb collisions are used to investigate cold nuclear...
We present the xFitter project which provides an open-source software framework for the determination of the proton's parton distribution functions and for the interpretation of the physics analyses in the context of Quantum Chromodynamics. The project has been used recently for a number of analyses performed by the LHC collaborations and theory community, which are summarised briefly. The...
Results of searches for the production of supersymmetric partners of gluons and quarks are presented. They are based on pp collisions recorded by the CMS experiment at sqrt(s) = 13 TeV. The searches are performed in final states with 0, 1, or more leptons and are either generic, or specifically designed for the production of third-generation squarks. In the most favorable scenarios, mass...
In the absence of forward proton tagging, exclusive processes can be distinguished in the central part of the ATLAS detector exploiting the large rapidity gap in the central region and the absence of charged particles reconstructed in the inner tracking detector. This strategy has been exploited to study the exclusive production of dilepton pairs in the data taken at centre-of-mass energies of...
Precision data taken in e+e- annihilation at or near the Υ(4S) by the Belle experiment has been instrumental in the extraction of spin dependent and integrated fragmentation functions. In this talk, we report our measurement on the invariant-mass and fractional-energy dependence of inclusive production of di-hardons. We also report on the production rate of hyperons and charmed baryons, the...
The fastNLO and APPLgrid projects provide a fast and flexible way to reproduce the results of perturbative QCD cross section calculations with any input parton distribution functions. The latest developments from these projects
are presented with particular emphasis on the common APPLfast interface to the NNLOJET calculation for general cross section calculations at next-to-next-to-leading...
Thanks to an improved comover interaction model, we show that we can reach a global and coherent de- scription of bottomonium suppression in both proton-nucleus and nucleus-nucleus collisions as measured by the CMS and ATLAS collaboration at the LHC. The measured relative suppression of the excited bottomonium states as compared to their ground state in proton-nucleus collisions allows us to...
Despite the absence of experimental evidence, weak scale supersymmetry remains one of the best motivated and studied Standard Model extensions. This talk summarises recent ATLAS results on inclusive searches for supersymmetric squarks and gluinos, including third generation squarks produced in the decay of gluinos. The searches involve final states containing jets, missing transverse momentum...
The CT-PPS (CMS-TOTEM Precision Proton Spectrometer) detector system consists of silicon tracking stations as well as timing detectors to measure both the position and direction of protons and their time-of-flight with high precision. They are located at around 200 m from the interaction point in the very forward region on both sides of the CMS experiment. CT-PPS is built to study Central...
The recently completed 12 GeV upgrade of Jefferson Lab's Continuous Electron Beam Accelerator Facility (CEBAF) has established a unique worldwide capability for the precision study of a variety of inclusive, semi-inclusive, and exclusive reactions in deep inelastic electron-nucleon and electron-nucleus scattering. The near-doubling of CEBAF's maximum electron beam energy to 11 GeV (for...
The correlation between the longitudinal polarization of a fragmenting quark and the transverse momenta of the produced hadrons was predicted over two decades ago. Nevertheless, experimental searches in the electron-positron annihilation process, both through the so-called jet handedness measurement by the SLD collaboration and more recently via the helicity-dependent dihadron fragmentation...
In this talk, we present a dedicated analysis of existing Monte Carlo methods in global QCD analysis. We critically examine the interpretability of uncertainties on extracted quantities, such as parton densities or fragmentation functions against nested sampling and more traditional approaches using Hessian methodology. We discuss how in some cases the inclusion of resampling, partition, and...
The LHCb experiment is designed to study heavy hadrons produced in proton-proton collisions at the LHC.
Charmed and charmonium hadrons produced in the pp-collision or in b-hadron decays are studied to identify new states, confirming or disproving those recently claimed, and establishing their quantum numbers. The spectroscopy of heavy baryons is also explored with observations of doubly...
Naturalness arguments for weak-scale supersymmetry favour supersymmetric partners of the third generation quarks with masses not too far from those of their Standard Model counterparts. Top or bottom squarks with masses less than or around one TeV can also give rise to direct pair production rates at the LHC that can be observed in the data sample recorded by the ATLAS detector. The talk...
Jefferson Lab recently completed an electron beam energy upgrade from 6 to 11 GeV. New experiments to study the structure of the nucleon have begun collecting data or are under preparation. The presentation will give an overview of the available detectors and targets in the three experimental halls and outline their experimental programs to image the nucleon three-dimensionally.
The TOTEM experiment at the interaction point 5 of the LHC has measured the total, elastic and inelastic proton-proton cross sections in a centre-of-mass energy range from 2.76 to 13 TeV, in dedicated fills with special beam optics.
Most recently, TOTEM has performed the first measurement of the ρ parameter at $\sqrt{s} = 13$ TeV, where rho is the ratio between the real and the imaginary...
We present our recent calculations of the complete set of the leading-twist quark-polarization-dependent dihadron fragmentation functions (DiFFs) to pion pairs. The quark-jet framework is used to model the sequential hadronization of a polarized quark into hadrons, where the polarization transfer to the remnant quark in each hadron emission step is calculated using the spin density matrix...
Which hadronic experiments constrain the PDF dependence of the Higgs boson cross section? What constrains the strangeness PDF better: LHC vector boson production, (SI)DIS, or jet production? We present a new technique to quantitatively answer such questions without performing a full PDF fit or PDF reweighting. The technique employs the Hessian method and takes into account the (un)correlated...
Heavy quark spectroscopy and exotic states are studied with the ATLAS detector, mainly thorough final states containing muon pairs from J/psi decays. The latest results on searches for exotic (tetra- / penta-quark) states in ATLAS are presented.
The MSSM predicts the existence of additional neutral and charged Higgs bosons. This presentation will discuss results from recent searches for these particles in several decay channels based on collision data collected at 13 TeV, and their interpretation within the MSSM.
In perturbative QCD, the masses of the hadrons involved in high energy reactions can usually be neglected. In this talk, I will discuss one case in which this may not be a good approximation, namely production of Kaons in electron-proton collisions at low (and not so low) beam energies. In particular, I will present a recent proposal to include hadron masses in theoretical calculations,...
The LHC is bringing us lots of very precise measurements. The calculation of the corresponding theoretical prediction with the same precision is very time consuming in general. It is then a very challenge work to study the impact on Parton Distribution Functions(PDFs) from the precision measurements efficiently. We propose to boost the procedure by using ePump, the Error PDF Updating Method...
Jefferson lab's (JLab) CEBAF (now upgraded CEBAF12) accelerator's fixed target experiments give an unique opportunity to study a wide range of phenomena in nuclear medium using Deep Inelastic Scattering (DIS) measurements. Particularly CLAS Eg2 experiment, where different types of nuclei were exposed to electron beam, have provided important information for nuclear hadronization, hadronic and...
Precision phenomenology at the LHC requires accounting for both higher-order QCD and electroweak corrections as well as for photon-initiated subprocesses. Building upon the recent NNPDF3.1 fit, in this work the photon content of the proton is determined within a global analysis supplemented by the LUXqed constraint relating the photon PDF to lepton-proton scattering structure functions:...
We report the measurements of gamma gamma ―> eta_c(1S), eta_c(2S)―>eta' pi+ pi- with eta' decay to gamma rho and eta pi+ pi- using 941 fb-1 of data collected with the Belle detector at the KEKB asymmetric-energy e+ e- collider. First observation of eta_c(2S)―>eta' pi+ pi- with a significance 5.5 \sigma including systematic error is obtained. The products of the two-photon decay width and...
Jefferson Laboratory has an extensive program of Deep Virtual Exclusive Scattering (DVES). I will review salient results from the 6 GeV era, and present the status and goals of both Deep Virtual Compton Scattering (DVCS) and Deep Virtual Meson Production (DVMP). A set of DVCS and exclusive $\pi^0$ measurements from 7 to 11 GeV have been completed in Hall A. A first JLab observation of...
When discussing the future searches for New Physics, electron-positron and proton-proton collider dominate the agenda, the choice being between a clean environment and higher energy. In this talk I will show with two concrete examples (Long-Lived Charged particles in SUSY and Higgs rare decays) how electron-proton colliders combine a clean environment with energies beyond the reach of most...
We consider lepton-jet correlations in deep inelastic scattering (DIS) as a unique probe of the nucleon/ nuclei tomography. We demonstrate the relevant QCD factorization in terms of transverse momentum dependent quark distributions (TMDs), soft functions and jet functions associated with the final state jet. All relevant large logarithms are resummed to next-to-leading logarithmic (NLL) order....
The dynamics of gluons in high energy proton and nuclei interactions remain an elusive process. Gluon interactions can be accessed via both light and heavy flavor hadron production at the PHENIX experiment at RHIC. In particular, via systematically measuring the nuclear modification in light hadron production in p+A and light-ion-A collisions at $\sqrt{s_{NN}} = 200$ GeV, we observed a...
Several theories beyond the Standard Model predict the existence of new heavy particles decaying into pairs of gauge bosons. In this presentation the latest ATLAS results on searches for resonances decaying into pairs of W or Z bosons or photons, or into a Z boson and a photon, based on 36 fb-1 of pp collision data collected at 13 TeV will be discussed.
We describe the inclusion of the photon as an additional component of the proton in the MMHT framework. The input for the photon is based very directly on the recent LUX determination. We describe the similarities and differences above the input scale and the contribution from both leading twist and higher twist contributions, and their uncertainties. We study the impact on the other PDFs and...
The potential of the future electron-proton collider facilities LHeC and FCC-eh for electroweak (EW) physics is studies using simulated neutral-current and charged-current DIS cross section data.
These measurements will allow for high precision determinations of the parameters of the EW theory, such as the weak boson masses and the couplings of the light quarks to the Z boson. The potential...
The unique acceptance of the LHCb experiment at the LHC offers the ability to make studies of QCD that are complementary to those made at the other LHC experiments.
A selection of recent results will be presented, including production measurements, inelastic cross-section measurements, and studies of correlations in particle production.
We report some of the most recent results in studying different aspects of QCD with about 500 fb$-1$ of data collected by the BaBar experiment at the $e^+e^-$ $B$-factory PEP-II.
Among these, we present a high precision measurement of the mass difference between the $D^*(2010)^+$ and $D^+$ mesons using the decay chain $D^*(2010)^+ \to D^+ \pi^0$, with $D^+ \to K^- \pi^+ \pi^+$. This...
Generalized parton distributions embody information on both the longitudinal momentum of the quarks as well as their transverse position and thus allow determining a 3-dimensional image of the nucleon. For transversely polarized quarks and or nucleons, the resulting transverse deformation of these images provides new insight on nucleon spin structure and spin-orbit correlations. Twist-3 GPDs...
Searches for additional scalar bosons with the Run 2 data at CMS are reviewed.
Heavy quark pair production in minimum bias p+p and p+A collisions has been studied extensively in the CGC framework and compared successfully to both the RHIC and LHC data on $J/\psi$ production [1, 2], $\psi(2S)$ production [3] and $D$-meson production [4]. We first present an update in this framework based on comparisons to the latest LHC and RHIC data on p+p and light-heavy ion collisions....
In this talk we present an overview of top physics at two possible future electron-proton (ep) colliders at the high energy frontier, the LHeC and the FCC-eh. Selected topics include but are not limited to top structure function, top parton distribution functions, top spin polarization, top electric charge, measurement of Vtb, anomalous ttg, ttZ, tbW, tqg, tqH couplings and CP phase
of ttH...
K->pinunu is one of the theoretically cleanest meson decay where to look for indirect effects of new physics complementary to LHC searches. The NA62 experiment at CERN SPS is designed to measure the branching ratio of the K+->pi+nunu decay with 10% precision. NA62 took data in 2015-2017; the analysis of a partial data set allows to reach the Standard Model sensitivity. The status of the...
Being the "mother distributions" of all types of two-parton correlation functions, generalized TMDs (GTMDs) have garnered a lot of attention. We address the important question of how to access GTMDs in physical processes. Recently, we have shown that quark GTMDs can in principle be probed through the exclusive pion-nucleon double Drell-Yan process, where the focus was on two particular GTMDs...
Fits to the final combined HERA deep-inelastic scattering cross-section data within the conventional DGLAP framework of QCD have shown some tension at low x and low Q2. A resolution of this tension incorporating ln(1/x)-resummation terms into the HERAPDF fits is investigated using the xFitter program. The kinematic region where this resummation is important is delineated. Such high-energy...
The large dataset collected so far during Run 2 of the LHC at a centre-of-mass energy of 13 TeV provides a significantly improved sensitivity for discovery of new physics with respect to Run 1. Searches for new resonances in di-boson final states (VV, VH, HH, where V = W, Z) with the CMS detector are presented. The analyses are optimised for high sensitivity over a large range in resonance...
We report on a recent computation of the NLO inclusive photon cross section using the Color Glass Condensate framework at the RHIC and LHC energies. Our result is appropriate for collisions where a dilute projectile (proton) hits a dense target (a proton or a heavy ion). We will briefly elucidate the main analytic NLO formula obtained in [1], while the main focus of this contribution are the...
The LHeC and the FCC-eh at CERN are projected machines that will deliver ep collisions with center-of-mass energies in the TeV range and luminosities of order $10^{34}$ cm$^{−2}$s$^{−1}$. In this talk, new results will be presented on future precision Higgs SM properties in these machines, as well as new prospects for searches for exotic Higgs related phenomena in ep collisions at high energies.
The property of tau neutrino is not well known, due to difficulty of its production and detection.
The comparison of the neutrino-nucleon cross-section of tau neutrinos and other neutrino flavours is one of the interesting topics.
The tau neutrino cross-section has been measured by the DONUT experiment, but with a large statistical error of $\sim30\%$ and a systematical uncertainty of...
Generalized parton distributions (GPDs) have been investigated in the deeply virtual Compton scattering (DVCS) to solve the proton spin puzzle. On the other hand, the generalized distribution amplitudes (GDAs) can be studied in the two-photon process $\gamma^*\gamma→h \bar{h}$ which is accessible at KEKB. Namely, the GDAs are the s-t crossed quantities of the GPDs. In 2016, the differential...
SHIP is a new general purpose fixed target facility, whose Technical Proposal has been reviewed by the CERN SPS Committee and by the CERN Research Board. The two boards recommended that the experiment proceeds further to a Comprehensive Design phase in the context of the new CERN Working group "Physics Beyond Colliders", aiming at presenting a CERN strategy for the European Strategy meeting...
We report a new QCD global analysis with a simultaneous extraction of polarized and unpolarized parton densities and fragmentation functions from the available polarized and unpolarized DIS, SIDIS and SIA data sets
The ridge structure in two-particle correlations produced in high multiplicity collisions at the LHC have been examined in the Color Glass Condensate formalism. In this formalism it was found that in the dilute-dilute nucleus limit, corresponding to glasma graphs, the ridge structure was due to the Bose enhancement associated with two-gluon production, with a successful phenomenology developed...
The LHeC and the FCC-eh at CERN are projected machines that will deliver ep collisions with center-of-mass energies in the TeV range and luminosities of order $10^{34}$ cm $^{-2}$s$^{-1}$. In this talk, new results will be presented on prospects for BSM searches in both machines.
We present a determination of parton densities at NLO obtained with the Parton Branching method using HERA precision data. The parton densities are obtained with the standard and angular ordering evolution scales. For integrated pdfs a significant effect is observed.
The transverse momentum dependent (TMD) densities, automatically obtained with the Parton Branching method, are applied to LHC...
Generalized Parton Distributions (GPDs) encode the correlations between longitudinal momentum and transverse position of partons inside hadrons and can give access to a picture of the nucleon structure in 2+1 dimensions. They have been studied theoretically and experimentally for almost two decades and a new experimental era is starting (at JLab and COMPASS currently, and in the future at an...
Searches for heavy neutral lepton (HNL) production in charged kaon decays
using the data collected by the NA62 experiment at CERN are reported. Upper
limits are established on the elements of the extended neutrino mixing
matrix for heavy neutral lepton mass in the range 130-450 MeV, improving on
the results from previous HNL production searches. The status and prospects
of searches for lepton...
In this contribution I will present a determination of the Fragmentation Functions (FFs) of unidentified charged hadrons at next-to-leading order in quantum chromodynamics based on the NNPDF methodology. The analysis includes cross-section data for single-hadron production in electron-positron annihilation, from a variety of experiments, and in proton-(anti)proton collision from the Tevatron...
Measurements of top quark properties using data collected by the CMS experiment at 13 TeV are presented. The top quark mass is measured in the lepton+jets channel is consistent with the CMS measurements of Run-1. The top quark mass is also studied as a function of the event kinematical properties. For the first time at the LHC, the width of the top quark is directly probed during Run-2, in...
The contribution of the quark and gluon helicity distributions to the proton spin requires integrating these helicity PDFs over the entire range of x. This necessarily involves an extrapolation of the measured PDFs at finite values of x into their small-x asymptotics. As is well-known in the case of the unpolarized quark and gluon distributions, the small-x asymptotics are governed by...
The Belle II experiment is a substantial upgrade of Belle detector and will operate at the SuperKEKB energy-asymmetric $e^+e^-$ collider. The accelerator has successfully completed the first phase of commissioning; collisions will start early April 2018. The design luminosity is $8 \times 10^{35}$ cm$^{-2}$s$^{-1}$ and the Belle II experiment aims to record 50 ab$^{-1}$ of data, a factor of 50...
We study the kaon multiplicity of semi-inclusive DIS off the deutron target with the updated parton distribution functions and fragmentation functions and compare our result with the HERMES data and COMPASS data. We demonstrated the tension between the HERMES data and COMPASS data and will provide our opinion about this tension. We will make comment about the extarcted values of the strange...
The latest measurements of the top quark mass using the ATLAS experiment are presented. A measurement based on a multi-dimensional template fit that can constrain the uncertainties on the energy measurements of jets is presented and combined with measurements using dilepton and all-hadronic events. In addition an analysis of the top quark mass using leptonic kinematic variables is discussed....
The Compact Linear Collider (CLIC) is a proposed high-luminosity linear
electron-positron collider operated at energies from the top pair
production threshold up to 3 TeV. With its high luminosity and flexible
collision energy CLIC offers a wide spectrum of possible physics research,
from precision measurement of Standard Model parameters to searches for
new particles and new physics...
We will present results on the nucleon spin decomposition and the momentum distribution among quarks in the nucleon. Techniques for lattice QCD simulations at the physical pion mass applied for the computation of sea-quark and gluon contributions will be presented. We will discuss several challenges and perspectives for future developments.
We perform a study on the direct measurement of $\rm V_{td}$ and $\rm V_{ts}$ CKM matrix elements, at the electron proton colliders, through W boson and bottom quark associated production channel as well as W boson and jet associated production channel. The W and bottom(jet) final states can be produced by s-channel single top decay or t-channel top exchange. We find even at the current LHC...
The $K^−$ over $K^+$ multiplicity ratio is measured in deep-inelastic scattering, for the first time for kaons carrying a large fraction z of the virtual-photon energy. The data were obtained by the COMPASS collaboration using a 160 GeV muon beam and an isoscalar $^6$LiD target. The regime of deep-inelastic scattering is ensured by requiring $Q^2>1$ (GeV/$c)^2$ for the photon virtuality and...
We study the theoretical uncertainties in the determination of the top-quark mass using next-to-leading-order (NLO) generators interfaced to parton showers (PS) that have different levels of accuracy. Specifically we consider three generators: one that implements NLO corrections in the production dynamics, one that includes also NLO corrections in top decay in the narrow width approximation,...
In this talk I will present preliminary results on π+, π- and π0 multiplicity ratios measured as a function of multiple kinematical variables in semi-inclusive DIS on three nuclei (C, Fe, Pb) normalized to deuterium . The series of measurements were performed at Jefferson Lab with 5.014 GeV electron beam incident on a double-target system in which liquid deuterium and one of the solid targets...
We provide a first calculation of the complete next-to-leading order QCD corrections for heavy flavor contributions to the inclusive structure function $g_1$ in longitudinally polarized deep-inelastic scattering. The results are derived with largely analytical methods and retain the full dependence on the heavy quark’s mass. We discuss all relevant technical details of the calculation and...
We calculate the different angular distribution spectra of $\gamma$-jet and jet-jet pairs in associated $\gamma+2$ jet production at the energies of the Tevatron and the LHC Colliders in the leading order approximation of the parton Reggeization approach [1-3]. Last one is based on high-energy factorization ($k_T-$factorization) and L.N. Lipatov's Effective Theory of Reggeized gluon and...
The bottomonium spectrum up to n = 3 is studied within Non-Relativistic Quantum Chromodynamics up to N3LO. We consider finite charm quark mass effects both in the QCD potential and the MS-pole mass relation up to third order in the Upsilon-scheme counting. The u = 1/2 renormalon of the static potential is canceled by expressing the bottom quark pole mass in terms of the MSR mass. A careful...
We present recent results on diffraction with the CMS and TOTEM experiments.
We study azimuthal ratios in Mueller-Navalet jets after imposing a rapidity veto constraint. In particular, we restrict the minijet radiation activity by not allowing subsequent emissions to be closer in rapidity than some fixed value b, the value of the rapidity veto. Previous studies in the literature suggest that for the NLL BFKL Green's function a rapidity veto with a value of two units of...
Light-by-light (LbyL) scattering ($\gamma\gamma \rightarrow \gamma\gamma$) is a fundamental quantum-mechanical process with tiny cross sections. Studies of LbyL scattering, using the large photon fluxes from ultraperipheral PbPb collisions at sqrt(s_N) = 5.02 TeV at the LHC, will be reported based on the evidence of a signal corresponding to an integrated luminosity of 391 $\mu b^{-1}$. The...
To simplify the calculation of DIS processes, many papers employed a form of the leptonic tensor which will lead to wrong results when the transverse momentum or rapidity of a final-state hadron is measured in the laboratory frame. Among these papers are there some highly cited ones and those employed by the event generators. To this end, many experimental data need to be reanalysed. I will...
The $p_\perp$ dependence of the nuclear modification factor $R_{AA}$ measured in PbPb collisions at the LHC exhibits a universal shape, which can be very well reproduced in a simple energy loss model based on the Baier-Dokshitzer-Mueller-Peigné-Schiff medium-induced gluon spectrum. The scaling is observed for various hadron species ($h^\pm$, $D$, $J/\psi$) in different centrality classes and...
Latest results on inclusive top quark pair and single top quark production cross sections are presented using proton-proton collision data collected by CMS at different centre-of-mass energies, including 5 TeV. The single top quark analyses investigate separately the production of top quarks via t-channel exchange, in association with a W boson (tW) or via the s-channel. Final states with at...
Flavor-changing neutral-current (FCNC) decays of the $B$ and $D$ mesons are strongly suppressed in the Standard Model (SM) because they cannot be produced at tree level, and occur first at one-loop level. Therefore, they are sensitive probes for contributions beyond the SM, as heavy mediator can also occur in these loop processes. The analyses presented here are based on the entire dataset...
Results of searches for the direct production of sleptons, charginos and neutralinos are presented. Sensitivity to these low cross section modes has been obtained based on the first large dataset of pp collisions recorded by the CMS experiment at sqrt(s) = 13 TeV. The searches are typically performed in final states with two or more leptons. In order to obtain sensitivity to compressed mass...
This paper explores the effects of both finite width and interference (with background) in the single production and decay of extra heavy quarks with charge +2/3 and -1/3 at the Large Hadron Collider (LHC). This dynamics is normally ignored in standard experimental searches and we assess herein the regions of validity of current approaches, using a model independent parametrization. We also...
The phenomenological study of the spin dependent ($g_1^{p,n}$) structure functions of the nucleon has been carried out using the polarized distribution functions of the quarks $\Delta q(x)$. In light of the improved precision of the world data, the $p$ and $n$ longitudinal spin asymmetries ($A_1^p(x)$ and $A_1^n(x)$) have been calculated. The ratio of the $n$ and $p$ structure functions...
We investigate the spin-spin correlations of logitudinally-polarized quark in a longitudinally-polarized proton $\rho_{\Lambda \lambda}$, transversely-polarized quark in transversely-polarized proton $\rho^i_{\Lambda_{T} \lambda_{T}}$, transversely-polarized quark in longitudinally-polarized proton $\rho^{i}_{\Lambda \lambda_T}$ and longitudinally-polarized quark in transversely-polarized...
We present the first study of the color-singlet (CS) $J/\psi$ leptoproduction at QCD next-to-leading order (NLO). This process is extremely difficult. The CS $J/\psi$ hadroproduction at NLO was studied in 2007, ten years has passed since then, the study of the $J/\psi$ leptoproduction at NLO was missing until we finished this work in May, 2017. This talk will present our results, and discuss...
A study of the latest color-reconnection models in QCD is performed with CMS data. The so called MPI-based, QCD-inspired and gluon-move models are studied within Pythia8, and the tuning parameters for the color reconnection and multiple parton interactions are extracted simultaneously from data. The different tunes are compared with top quark distributions.
Exclusive vector meson electroproduction over a broad $Q^2$ range offers a unique opportunity to probe the gluon structure of nuclei to measure nuclear shadowing, and to search for gluon saturation and/or the colored glass condensate at an Electron-Ion Collider. Understanding the kinematic distributions and cross sections for specific processes can impact detector design to maximize their...
The potential of the future electron-proton collider facilities LHeC and FCC-eh for electroweak (EW) physics is studies using simulated neutral-current and charged-current DIS cross section data.
These measurements will allow for high precision determinations of the parameters of the EW theory, such as the weak boson masses and the couplings of the light quarks to the Z boson. The potential...
In this talk, I will argue that sea quark Sivers function can be dynamically generated through spin dependent odderon. Due to the C-odd nature of odderon, the derived quark Sivers function and anti-quark Sivers function at small x are the same in size, but differ by a minus sign. We further show that sea quark Sivers function computed in CGC is reduced to that obtained in collinear twist-3...
