Conveners
Strong interactions and Hadron Physics
- Gunar Schnell (University of the Basque Country UPV/EHU)
- Maria Ubiali
Strong interactions and Hadron Physics
- Marco Pappagallo (INFN & University of Bari)
- Alice Ohlson (Lund University)
Strong interactions and Hadron Physics
- Maria Ubiali
- Giovanni Abbiendi (Istituto Nazionale di Fisica Nucleare)
Strong interactions and Hadron Physics
- Maria Ubiali
- Alice Ohlson (Lund University)
Strong interactions and Hadron Physics
- Giovanni Abbiendi (Istituto Nazionale di Fisica Nucleare)
- Gunar Schnell (University of the Basque Country UPV/EHU)
Strong interactions and Hadron Physics
- Marco Pappagallo (INFN & University of Bari)
- Gunar Schnell (University of the Basque Country UPV/EHU)
Strong interactions and Hadron Physics
- Giovanni Abbiendi (Istituto Nazionale di Fisica Nucleare)
- Maria Ubiali
Strong interactions and Hadron Physics
- Giovanni Abbiendi (Istituto Nazionale di Fisica Nucleare)
- Alice Ohlson (Lund University)
Strong interactions and Hadron Physics
- Maria Ubiali
- Gunar Schnell (University of the Basque Country UPV/EHU)
Strong interactions and Hadron Physics
- Alice Ohlson (Lund University)
- Marco Pappagallo (INFN & University of Bari)
Strong interactions and Hadron Physics
- Marco Pappagallo (INFN & University of Bari)
- Giovanni Abbiendi (Istituto Nazionale di Fisica Nucleare)
Strong interactions and Hadron Physics
- Marco Pappagallo (INFN & University of Bari)
- Alice Ohlson (Lund University)
The HERAPDF2.0 ensemble of parton distribution functions (PDFs) was introduced in 2015. The final stage is presented, a next-to-next-to-leading-order (NNLO) analysis of the HERA data on inclusive deep inelastic $ep$ scattering together with jet data as published by the H1 and ZEUS collaborations. A perturbative QCD fit, simultaneously of $\alpha_s(M_Z^2)$ and the PDFs, was performed with the...
We discuss recent developments related to the the latest release of the NNPDF family of global analyses of parton distribution functions: NNPDF4.0. This PDF set expands the NNPDF3.1 determination with 44 new datasets, mostly from the LHC. We derive a novel methodology through hyperparameter optimisation, leading to an efficient fitting algorithm built upon stochastic gradient descent....
We present fits to determine parton distribution functions (PDFs) using a diverse set of measurements from the ATLAS experiment at the LHC, including inclusive W and Z boson production, ttbar production, W+jets and Z+jets production, inclusive jet production and direct photon production. These ATLAS measurements are used in combination with deep-inelastic scattering data from HERA. Particular...
With detector instrumented in the forward region, the collected Z boson events in the LHCb acceptance can be used to probe the proton structure in a phase space region not accessible by other LHC experiments. In this talk, the latest Z boson production measurements will be presented, as well as the measurement of Z+ c jet events for probing intrinsic charm. The potential contributions of the...
The QCD strong coupling (alpha_s) and the parton distribution functions (PDFs) of the proton are fundamental ingredients for phenomenology at high-energy facilities such as the Large Hadron Collider (LHC).
It is therefore of crucial importance to estimate any theoretical uncertainties associated to them.
Both alpha_s and PDFs obey their own renormalisation-group equations (RGEs) whose...
We present EKO and yadism, a new DGLAP evolution and DIS code respectively, able to provide PDF independent operators, for fast predictions evaluation.
They both support a wide range of physics and computational features, with a Python API to access the individual ingredients (e.g. strong coupling evolution), and file based output for a language agnostic consumption of the results. They are...
The LHeC and the FCC-he are the cleanest, high resolution microscopes that the world can build in the nearer future. Through a combination of neutral and charged currents and heavy quark tagging, they will unfold the parton structure of the proton with full flavour decomposition and unprecedented precision. In this talk we will present the most recent studies on the determination of proton...
In Lattice gauge theories , to calculate the PDFs from first principles
it is convenient to consider the Ioffe-time distribution defined through gauge-invariant bi-local operators with spacelike separation. Lattice calculations provide values for a limited range of the distance separating the bi-local operators. In order to perform the Fourier transform and obtain the pseudo- and the...
The measurement of neutral mesons in pp collisions allows a test of perturbative QCD calculations and represents an important baseline for heavy-ion studies. Neutral mesons are reconstructed in ALICE with multiple methods in a very wide range of transverse momenta and thus impose restrictions on the parton distribution functions and fragmentation functions over a wide kinematic region....
In this contribution, we present the latest measurements of $\mathrm{D}^0$, $\mathrm{D}^+$ and $\mathrm{D_s}^+$ mesons together with the final measurements of $\Lambda_\mathrm{c}^+$, $\Xi_\mathrm{c}^{0,+}$, $\Sigma_\mathrm{c}^{0,++}$, and the first measurement of $\Omega_\mathrm{c}^0$ baryons performed with the ALICE detector at midrapidity in pp collisions at $\sqrt{s}=5.02$ and $\sqrt{s}=13$...
I will discuss nonperturbative flavor correlations between pairs of leading and next-to-leading charged hadrons within jets at the Electron-Ion Collider (EIC). We introduce a charge correlation ratio observable $r_c$ that distinguishes same- and opposite-sign charged pairs. Using Monte Carlo simulations with different event generators, $r_c$ is examined as a function of various kinematic...
The observation of 3-Jpsi production in a single pp collision is reported. The results are based on the data collected by the CMS experiment in 13 TeV pp collisions. The measured effective double parton scattering cross section is compared to the previous measurements.
The LHCb experiment at the LHC is suited for studying how hadrons are formed from scattered quarks and gluons, in energetic proton-proton collisions. The hadronization and fragmentation processes can be studied via measurements such as those involving jet substructure. Equipped with a forward spectrometer, the LHCb experiment achieves an excellent transverse momentum for charged tracks, that...
The study of the associated production of vector bosons and jets constitutes an excellent environment to check numerous QCD predictions. Total and differential cross sections of vector bosons produced in association with jets have been studied in pp collisions using CMS data. Differential distributions as a function of a broad range of kinematical observables are measured and compared with...
The production of W/Z bosons in association with heavy flavor jets or hadrons at the LHC is sensitive to the heavy flavor content of the proton and provides an important test of perturbative QCD. We present the production of Z bosons in association with b-tagged large radius jets. The result highlights issues with modeling of additional hadronic activity and provides distinction between...
Understanding leading non-perturbative corrections, showing up as linear power corrections, is crucial to properly describe observables both at lepton and hadron colliders.
Using an abelian model, we examine these effects for the transverse momentum distribution of a $Z$ boson produced in association with a jet in hadronic collisions, that is one of the cleanest LHC observables, where the...
We present high-accuracy QCD predictions for the transverse-momentum (qT) distribution and fiducial cross sections of Drell-Yan lepton pairs produced in hadronic collisions. At small values of qT we resum to all perturbative orders the logarithmically enhanced contributions up to next-to-next-to-next-to-leading logarithmic (N3LL) accuracy, including all the next-to-next-to-next-to-leading...
The strong force is the least known fundamental force of nature, and the effort of precisely measuring its coupling constant has a long history of at least 30 years. This contribution presents a new experimental method for determining the strong-coupling constant from the Sudakov region of the transverse-momentum distribution of Z bosons produced in hadron collisions through the Drell-Yan...
We will present results for a new, high precision, extraction of the strong coupling, $\alpha_s$, at the tau mass scale based on a more precise, non-strange, inclusive vector isovector spectral function. The new spectral function is obtained from a combination of (i) ALEPH and OPAL results for the $2\pi$ pion and $4\pi$ pion tau decay channels, (ii) recent BaBar results for the $\tau \to K^-...
I will present NNLO QCD calculation for Wbb production at the LHC. The computation of two-loop scattering amplitude using finite-field framework will be discussed and phenomenological results at the LHC sqrt{s}=8 TeV will be shown. The use of different flavoured jet algorithms will be explored and the comparison with CMS data will be presented.
Measurements of jet production in proton-proton collisions at the LHC are crucial for precise tests of QCD, improving the understanding of the proton structure and are important tools for searches for physics beyond the standard model. We present the most recent set of inclusive jet measurements performed using CMS data and compare them to various theoretical predictions.
A measurement of the inclusive jet production in proton-proton collisions at the LHC at $\sqrt{s}=13$ TeV is presented. The double-differential cross sections are measured as a function of the jet transverse momentum $p_t$ and the absolute jet rapidity $|y|$. The anti-$k_t$ clustering algorithm is used with distance parameter of 0.4 (0.7) in a phase space region with jet $p_t$ from 97 GeV up...
The production of jets and prompt isolated photons at hadron colliders provides stringent tests of perturbative QCD. We present the latest measurements using proton-proton collision data collected by the ATLAS experiment at $\sqrt{s}=13$ TeV. Prompt inclusive photon production is measured for two distinct photon isolation cones, R=0.2 and 0.4, as well as for their ratio. The measurement is...
Isolated photon measurements in pp and p-Pb collision systems probe the initial state of the incoming nucleon or nucleus, providing the opportunity to constrain parton and nuclear parton density functions (PDFs), and probe cold nuclear matter effects. Measurements in small collision systems also offer a baseline for Pb-Pb collision measurements.
We present measurements by ALICE of inclusive...
Measurements of event shapes and jet substructure observables can serve as in-depth probes of the strong interactions. Data on deep-inelastic scattering collected at the HERA $ep$ collider using the H1 detector have been analysed in the kinematic region of large momentum transfer $Q^2>150$ GeV$^2$. Various new measurements of the hadronic final state, as listed in the following, are presented...
We present the first anti-kT jet spectrum and substructure measurements using the archived ALEPH e+e- data taken in 1994 at a center of mass energy of sqrt(s) = 91.2 GeV. Jets are reconstructed with the anti-kT algorithm with a resolution parameter of 0.4. It is the cleanest test of jets and QCD without the complication of hadronic initial states. The fixed center-of-mass energy also allows...
A proper understanding of non-perturbative effects, which manifest themselves as linear power corrections, is needed to describe many observables measured at colliders. We report on recent progress in the calculation of linear power corrections to shape variables such as the $C$-parameter and thrust in the three-jet region arising from infrared renormalons. Previously, only the results at the...
The Future Circular Collider (FCC) is a post-LHC project aiming at direct and indirect searches for physics beyond the SM in a new 100 km tunnel at CERN. In addition, the FCC-ee offers unique possibilities for high-precision studies of the strong interaction in the clean environment provided by e+e- collisions, thanks to its broad span of center-of-mass energies ranging from the Z pole to the...
At BESIII, the R value is measured with a total of 14 data points with the
corresponding c.m. energy going from 2.2324 to 3.6710 GeV.
The statistical uncertainty of the measured R is less than 0.6%. Two different
simulation models, the LUARLW and a new Hybrid generated, are used and give
consistent detection efficiencies and initial-state-radiation corrections. An
accuracy of better than...
We present a study of the process $e^+e^- \to \pi^+\pi^-\pi^0$ at $BABAR$ using the initial-state radiation technique. The analysis is based on the full $BABAR$ data set, 469 fb$^{-1}$, recorded at and near the $\Upsilon(4{\mathrm{S}})$ resonance. From the fit to the measured $3\pi$ mass spectrum we determine the products $\Gamma(V\to e^+e^-){\cal{B}}(V\to 3\pi)$ for the omega and phi...
We present new lattice results of the ETM Collaboration, obtained from extensive simulations of lattice QCD with dynamical up, down, strange and charm quarks at physical mass values, different volumes and lattice spacings, concerning the SM prediction for the so-called intermediate window (W) and short-distance (SD) contributions to the leading order hadronic vacuum polarization (LOHVP) term...
The anomalous magnetic moment of the muon $a_\mu = (g-2)_\mu/2$ has been measured at the Brookhaven National Laboratory in 2001 and recently at the Fermilab Muon $g - 2$ Experiment. The results deviate by 4.2 $\sigma$ from the Standard Model predictions, where the most dominant source of theoretical error comes from the Hadronic Leading Order (HLO) contribution $a_\mu^{\mathrm{HLO}}$. MUonE is...
The latest measurement of the muon g-2 announced at Fermilab exhibits a 4.2$\sigma$ discrepancy from the currently accepted Standard Model prediction. The main source of uncertainty on the theoretical value is represented by the leading order hadronic contribution $a_{\mu}^{HLO}$, which is traditionally determined through a data-driven dispersive approach. A recent calculation of...
The leading-order (LO) hadronic vacuum polarization (HVP) contribution to the muon $g$-$2$, $a_{\mu}^{\rm HVP}(\rm LO)$, is traditionally computed via dispersive "time-like" integrals using measurements of the hadronic production cross-section in $e^{-}e^{+}$ annihilations. An alternative method is provided by lattice QCD. At LO, simple "space-like" formulas are well-known and form the basis...
The energy dependency (running) of the strength of electromagnetic interactions $\alpha$ and of the mixing with weak interactions $\sin^2\theta_{\mathrm{W}}$ plays an important role in precision tests of the SM. The running of the former to the $Z$ pole is an input quantity for global electroweak fits, while the running of the mixing angle is susceptible to the effects of BSM physics,...
The differential cross section of proton-proton elastic scattering $d \sigma/dt$, as a function of the magnitude of the four-momentum transfer squared $|t|$, evolves in a consistent way with $\sqrt{s}$ at LHC energies, all the curves being translated in the ($|t|$, $d\sigma/dt$) plane for different center-of-mass energies. This means that the cross sections vary according to a scaling law in...
The elastic scattering of protons at 13 TeV is measured in the range of protons transverse momenta allowing the access to the Coulomb-Nuclear-Interference region. The data were collected thanks to dedicated special LHC beta* = 2.5 km optics. The total cross section as well as rho-parameter, the ratio of the real to imaginary part of the forward elastic scattering amplitude, are measured and...
Proton and neutron electric and magnetic form factors are the primary characteristics of their spatial structure and have been studied extensively over the past half-century. One of the recent focal points is their behavior at large values of the momentum transfer $Q^2$, where one expects to observe transition from nonperturbative to perturbative QCD dynamics and detect effects of quark...
KLOE and KLOE-2 data (almost 8 fb$^{-1}$) constitute a unique sample, rich in physics, and the largest dataset ever collected at an electron-positron collider operating at the $\phi$ peak resonance.
In total it corresponds to the production of about 24 billion $\phi$ mesons, whose decays include about 8 billion pairs of neutral K mesons and about 300 million $\eta$ mesons.
A wide hadron...
Hard Exclusive Meson Production and Deeply Virtual Compton Scattering (DVCS) are widely used reactions to study Generalised Parton Distributions (GPDs). Investigation of GPDs represents one of the main goals of the COMPASS-II program. Measurements of the exclusive processes were performed at COMPASS in 2016 and 2017 at the M2 beamline of the CERN SPS using the 160 GeV/$c$ muon beam scattering...
AMBER is a newly proposed fixed-target experiment at the M2 beam line of the SPS, devoted to various fundamental QCD measurements, with a Proposal recently approved by the CERN Research Board for a Phase-1 program and a Letter of Intent made public for a longer term program.
Such an unrivaled installation would make the experimental hall EHN2 the site for a great variety of measurements to...
We present a new approach to jet definition alternative to clustering methods, such as the anti-kT scheme, that exploit kinematic data directly. Instead the new method uses kinematic information to represent the particles in a multidimensional space, as in spectral clustering. After confirming its Infra-Red (IR) safety, we compare its performance in analysing $gg \rightarrow H_{125GeV}...
Multiplicity is one of the simplest experimental observables in collider events, whose importance stretches from calibration to advanced tagging techniques. We introduce a new (sub)jet multiplicity, the Lund multiplicity, for lepton and hadron collisions. It probes the full multiple branching structure of QCD and is calculable in perturbation theory. We introduce a formalism allowing us to...
Discriminating quark and gluon jets is a long-standing topic in collider phenomenology. In this paper, we address this question using the Lund jet plane substructure technique introduced in recent years. We present two complementary approaches: one where the quark/gluon likelihood ratio is computed analytically, to single-logarithmic accuracy, in perturbative QCD, and one where the Lund...
The identification of the origin of hadronic jets is a key aspect in particle physics at hadron colliders. In this talk I will discuss the separation of hadronic jets that contain bottom quarks (b-jets) from jets featuring only light partons using a newly developed approach reported in arXiv:2202.05082 [hep-ph].
This approach exploits QCD-inspired jet substructure observables, such as...
Monte Carlo event generators, including their core parton-shower component, are crucial for a wide range of physics applications at colliders. However, the current โleading logarithmicโ (LL) accuracy of parton showers is increasingly becoming a limiting factor in precision applications. This talk presents new โPanScalesโ dipole showers for hadron collisions, focusing on the physical...
A parton shower model is presented that is explainable and physics aware, and trainable solely based on the energy-momentum vectors of final state particles [1]. We show that it is possible to use such a white box AI approach to train a generativeโadversarial network (GAN) from a DGLAP-based parton shower Monte Carlo, where the inferred mechanisms can be fully understood by a human physicist....
Higher-order splitting kernels comprise an essential ingredient for enhancing the logarithmic accuracy of parton showers. Beyond NLL, collinear dynamics of quark and gluon splitting at NLO is encoded in the triple-collinear splitting functions. This talk provides latest insights into various ingredients that enter the construction of higher-order parton showers. First, I will show that...
Being motivated mainly by the LHC physics, the currently used Monte Carlo Event Generators (MCEGs) lack of the quark spin degree of freedom in their hadronization models. In the recent years, however, the importance of quark spin related effects in hadronization such as the Collins effect has been brought to light by a vivid theoretical and experimental activity. Remarkably, global analyses of...
General purpose Monte Carlo event generators are a vital component of the feedback loop between experimental measurement, where they are used to model detector effects and correct for them, and theory, where comparisons to data can inform further improvements in the models. However, most tuning exercises are performed on LHC or Tevatron data, with the most recent RHIC tune being the...
This talk presents ATLAS recent measurements of distributions sensitive to Underlying event, the hadronic activity observed in relationship with the hard scattering in the event. The rates and the total transverse momentum was measured for Kaons, Lambda baryons and their ratios as a function of the leading track-jet and is compared to MC predictions which in general fail to describe the data....
Measurements of the production of hadrons containing beauty quarks in pp and p-Pb collisions provide an important test of quantum chromodynamics calculations. They also set the reference for the respective measurements in heavy-ion collisions, where the properties of the quark-gluon plasma are investigated. The excellent particle identification, track and decay-vertex reconstruction...
We report on calculations of differential cross sections for $c \bar c$- and $b \bar b$-dijet production in $pp$-scattering at $\sqrt{s} = 13$ TeV in the $k_T$-factorization and hybrid-factorization approaches with different unintegrated parton distribution functions (uPDFs). We present distributions in transverse momentum and pseudorapidity of the leading jet, rapidity difference between the...
Recent results from the proton-proton collision data taken by the ATLAS experiment on the charmonium and B meson production and decays will be presented. The measurement of $J/\psi$ and $\psi(2S)$ differential cross sections will be reported as measured on the whole Run 2 dataset. The measurement of the differential cross sections of $B^+$ production at 13 TeV and their ratios to those...
Our understanding of hadronic collisions has been challenged by the intriguing observation of collective phenomena in events with high charged-particle multiplicity density in small systems. Such high multiplicities are expected in events with multiple parton-parton interactions (MPI). At the LHC, MPIs affect the production of heavy-quarks (charm and beauty), and the large statistics samples...
We study the different mechanisms contributing to photoproduction of quarkonium pairs in NRQCD at the EIC, namely via unresolved and resolved photons. In the latter case, we study the relevance of double parton scatterings along the lines of our recent study on 4-jet photoproduction[1]. Like for the hadroproduction case [2,3,4,5,6,7], quarkonium-pair photoproduction probes, in different...
In this talk we present the most recent extraction of unpolarized transverse-momentum-dependent (TMD) parton distribution functions (PDFs) and TMD fragmentation functions (FFs) from global data sets of Semi-Inclusive Deep-Inelastic Scattering (SIDIS), Drell-Yan and Z boson production. The fit is performed at the N3LL logarithmic accuracy in the resummation of qT-logarithms and features...
This talk presents results, based on the papers
arXiv:2201.07114 [hep-ph], arXiv:2109.12051 [hep-ph],
Phys. Lett. B 806 (2020) 135478 [arXiv:2002:12810 [hep-ph]],
on the determination of the TMD parton distributions and
rapidity evolution kernel from transverse momentum spectra. It
is shown that the bias induced by PDF in TMD extractions
is alleviated if PDF uncertainties are taken...
The Parton Branching (PB) approach provides a way to obtain transverse momentum dependent (TMD) parton densities. Its equations are written in terms of splitting functions and Sudakov form factors and can be solved with Monte Carlo methods. Even though the transverse momentum is known in every branching, the PB method currently uses the DGLAP splitting functions, which assume that the parton...
Azimuthal single- and double-spin asymmetries measured at Hermes in semi-inclusive leptoproduction of pions, charged kaons, protons, and antiprotons from a transversely polarized hydrogen target are presented. The results of a re-analysis of the previously published Collins and Sivers asymmetries, extended to include protons and antiprotons as well as an extraction in a multi-dimensional...
The lepton-jet momentum imbalance in deep inelastic scattering events offers a useful set of observables for unifying collinear and transverse-momentum-dependent frameworks for describing high energy Quantum Chromodynamics interactions. A recent first measurement was made [1] of this imbalance in the laboratory frame using positron-proton collision data recordedf with the H1 experiment at HERA...
This talk presents results, recently obtained in the papers Eur. Phys. J. C 82 (2022) 36 [arXiv:2112.10465 [hep-ph]] and arXiv:2204.01528 [hep-ph], on azimuthal correlations in di-jet and Z+jet processes at large transverse momenta. The results are computed by matching Parton - Branching (PB) TMD parton distributions and showers with NLO calculations via MCatNLO. It is observed that the...
We study the polar and azimuthal decay angular distributions of $J/\psi$ mesons produced in semi-inclusive, deep-inelastic electron-proton scattering. For the description of the quarkonium formation mechanism, we adopt the framework of NRQCD, with the inclusion of the intermediate color-octet channels that are suppressed at most by a factor $v$ in the velocity parameter $v$ relative to the...
The LHCb experiment collected the world's largest sample of charmed hadrons during LHC Run 1 and Run 2. With this data set, LHCb is currently providing the world's most precise measurements of properties of charmed hadrons, as well as discovering many previously unobserved states. This talk reports on measurements of excited charm(-strange) mesons in amplitude analyses of beauty mesons...
Conventional doubly heavy hadrons, including quarkonium, are good probe for the non-perturbative regime of QCD, thus important to improve our understanding of the strong interaction. The LHCb experiment is dedicated to heavy flavour physics. The large heavy hadron dataset and excellent performance of the detector make it an ideal laboratory for studies of doubly heavy hadrons. The talk...
The large data sample accumulated by the Belle experiment at KEKB asymmetric energy $e^{+}e^{-}$ collider provides an important opportunities to study charmonium(-like) and bottomonium(-like) states. We report new results on $X(3872)$ decays to $J/\psi\omega$ and $\pi^+\pi^-\pi^0$ final states, as well as other studies on charmonium. Belle data taken with an energy scan around the...
The measurements of spectroscopy and decays of b-hadrons can provide invaluable experimental input to improve our knowledge of QCD. The LHCb experiment uniquely covers the b-hadron enriched kinematic region and has excellent performance in reconstructing and identifying b-hadron decays. It has been making leading efforts in such studies. In this talk, the latest results on b-hadron...
LHCb has recorded the largest sample of charm hadrons during Run 1 and Run 2 of the LHC (2011--2018). With these data, amplitude analyses of samples of unprecedented size are possible. Recent results of charm hadrons decays are shown.
The idea of diquarks as effective degrees of freedom in QCD has been a successful concept in explaining observed hadron spectra. Recently they have also played an important role in studying doubly heavy tetraquarks in phenomenology and on the lattice. The first member of this family of hadrons is the $T_{CC}$, newly discovered at LHCb.
Despite their importance, the colored nature of diquarks...
Many exotic resonances have been recently observed at the LHC and other experiments. In this report, CMS studies of exotic multiquark states are reported using the data collected in pp collisions at sqrt(s) = 13 TeV.
Recent results from the proton-proton collision data taken by the ATLAS experiment on exotic resonances will be presented. A search for $J/\psi\ p$ resonances in $\Lambda_b \to J/\psi\ p K$ decays with large $pK$ invariant masses will be reported. Studies of $Z_c$ states in $B$-meson decays with the Run 2 data at 13 TeV will also be discussed. Searches for exotic resonances in 4 muon final...
The discoveries of meson-like exotic states have been attracting huge interest from the hadron physics community. Studies on their spectroscopy can deepen our understanding of the internal structure and dynamics of hadrons. The LHCb experiment has been making significant contributions to such studies thanks to the large dataset provided by LHC and the delicate design of the detector. This talk...
The discovery of pentaquark candidates at LHCb in 2015 led to a renaissance of exotic hadron spectroscopy. There is yet no consensus on the nature of pentaquarks, calling for further experimental efforts. The large dataset and excellent detector performance give the LHCb experiment unprecedented capability in such study. In this talk, the latest results on pentaquark study from LHCb will be discussed.
Using a scan sample taken at center-of-mass energies from 3.773 GeV to 4.95 GeV with an integrated luminosity of 22/fb, the properties of XYZ states are investigated at BESIII. The cross sections of $e^+e^- \to D^{*+} D^{*-}$ and $D^{*+} D^-$, $e^+e^- \to K^+ K^- J/\psi$, $e^+e^- \to \pi^+ \pi^- \psi_2(3823)$, and $e^+e^- \to \Lambda \bar{\Lambda}$ are measured. The new decay modes of $X(3872)...
Belle II offers unique possibilities for the discovery and interpretation of exotic multiquark combinations to probe the fundamentals of QCD.
This talk present recent results on the amplitude analysis of the charmonium-like state $X(3940)$ and searches for the hidden bottom transition between $Y(10750)$ and $\chi_{bJ}$.
The LHCb collaboration recently discovered a doubly charmed tetraquark $T_{cc}$ with flavor $cc\bar u\bar d$ just $0.36(4)~$MeV below $D^0D^{*+}$ threshold. This is the longest lived hadron with explicitly exotic quark content known to this date. We present the first lattice QCD study of $DD^*$ scattering in this channel, involving rigorous determination of pole singularities in the related...
We discuss a strategy to study non-perturbatively QCD up to very high temperatures by Monte Carlo simulations on the lattice. It allows to investigate not only the thermodynamic properties of the theory but also other interesting thermal features. As a first concrete application, we compute the flavour non-singlet meson screening masses and we present the results of Monte Carlo simulations at...
The $_{\Lambda}^{3}\rm H$ is a bound state of proton (p), neutron (n) and $\Lambda$. Studying its characteristics provides insights about the strong interaction between the $\Lambda$ and ordinary nucleons. In particular, the $_{\Lambda}^{3}\rm H$ is an extremely loosely bound object, with a large wavefunction. As a consequence, the measured (anti-)$_{\Lambda}^{3}\rm H$ production yields in pp...
In the journey to explore the strong interaction among hadrons, ALICE has for the first time flared out its femtoscopic studies to nuclei. The large data sample of high-multiplicity pp collisions at $\sqrt{s}$ = 13 TeV allows the measurement of the proton-deuteron (p-d) and the hyperon-deuteron ($\Lambda$-d) momentum correlations. The femtoscopic study of these systems opens the door to...
Correlations between charged particles provide important insight about hadronization processes. We present recent results on Bose-Einstein two-particle correlation using ATLAS data at the center-of-mass energy of 13 TeV. Also, if available, the analysis of the momentum difference between charged hadrons in pp, p-lead, and lead-lead collisions of various energies is performed in order to study...
BESIII has the worldโs largest samples of $J/\psi$ and $\psi(3686)$ events from
$e^+ e^-$annihilations, which offer an ideal and clean laboratory to study light meson
spectroscopy , in particular for the search for QCD exotics. Recent important
achievements in this field, including the observation of a 1-+ state, $\eta_1(1855)$ in
$J/\psi->\gamma \eta \etaโ$, the observation of the...
The hybrid mesons form a part of the exotic spectrum of the standard model. The recent observation of the isoscalar hybrid, called the $\eta_1(1855)$, provides an important step towards the completion of the $1^{-+}$ nonet. In the present work, we analyze the masses and two-body decays of the members of this nonet using a model Lagrangian. The isovector $\pi_1(1600)$ has been studied...
The study of exotic mesons such as gluonic hybrids gives a greater insight into how quarks and gluons bind to form such states and hence increase our understanding of the fundamental strong force. Furthermore, the double pion photoproduction is known as a ideal tool for the investigation of nucleon resonances, especially the exotic meson states. Hereby, to study the interference of meson...
