Connecting experimental measurements, numerical simulations and microscopic theory to form a genuine understanding of nuclear matter in extreme conditions requires robust statistical tools. In this talk I will discuss Bayesian techniques, which allow the practitioner to make explicit her prior knowledge, as well as uncertainty, in a well controlled manner. As examples for application of...
I will discuss the rapid recent progress made in modelling neutron stars in
binary system and show how the inspiral and merger of these systems is more
than a strong source of gravitational waves. Indeed, while the gravitational
signal can provide tight constraints on the equation of state for matter at
nuclear densities, the formation of a black-hole--torus system can explain much
of the...
The equation of state (EoS) of nuclear matter is one of the key issues in understanding the physical
properties of neutron stars (NS). Currently, the strongest constraint comes from the fact that the maximum mass for NSs must be larger than about 2Mo, whereas the determination of the radius is still suffering of observational uncertainties and models dependence.
Gravitational wave (GW)...
Statistics plays a crucial role in the extraction of information from physics measurements, and its scope has been steadily increasing in the XXI century, pushed in particular by development of machine learning tools. In this talk will be given an introduction of the status of statistics practice, relying on the driving example of HEP, and a look at the goals for the three days of talks,...
Rare kaon decays belong to the class of flavour changing neutral current decays and are forbidden at leading order in the Standard Model. For this reason, these decays constitute attractive channels to look for new physics. The NA62 experiment (CERN) is starting this year to measure rare kaon decay amplitudes and it is important to have precise predictions of these quantities in the Standard...
Light cone distribution amplitudes are needed in the theoretical description of exclusive processes. I will summarize results on their first Gegenbauer moments obtained by recent lattice simulations and comment on attempts to directly compute them in coordinate space.
We report on a study of the Schwinger-Dyson equation (SDE) in the Euclidean formulation of local quantum gauge field theory, with Coulomb gauge condition $partial_i A_i = 0$. We compare the results of that study with a numerical simulation of lattice gauge theory and find that the infrared critical exponents and related quantities agree to within 1\% to 3\%. This raises the question, Why is...
We will update our continuum extrapolated result on the chiral
crossover temperature in QCD with (2+1)-flavor and physical quark
masses. Results are based on calculations with Highly improved
Staggered Quarks (HISQ) on three different lattices sizes (Nτ=6,8,12).
We systematically study all chiral second-order susceptibilities that
diverge in the ciral limit. From a Taylor expansion of...
The study of the Quark-Gluon Plasma created in ultrarelativistic heavy-ion collisions at the CERN-LHC is complemented by reference measurements in proton-lead (p--Pb) and proton-proton (pp) collisions, where the effects of multiple-parton interactions and hadronization beyond independent string fragmentation can be investigated.
In this talk, we present a Bayesian unfolding procedure to...
We calculate the equation of state at high temperatures in 2+1 flavor QCD using the highly improved staggered quark (HISQ) action. We study the lattice spacing dependence of the pressure at high temperatures using lattices with temporal extent (N_\tau= 6,\ 8,\ 10) and (12) and perform continuum extrapolations.
We also give a continuum estimate for the equation of state up to temperatures...
The property of color confinement ("C-confinement"), meaning that all asymptotic particle states are color neutral, holds not only in QCD, but also in gauge-Higgs theories deep in the Higgs regime. In this talk I will describe a new and stronger confinement criterion, separation-of-charge confinement or "S-confinement," which is an extension of the Wilson area-law criterion to gauge + matter...
New results in kaon physics from the NA62 experiment at CERN are presented, including the measurement of the K+ --> pi+ nu nu decay rate. NA62 short-term prospects and on-going analyses, including radiative kaon decay measurements and searches lepton number violation, are discussed. Finally, recent results on rare kaon decays from the NA48/2 experiment at CERN are presented.
Optimization problems in HEP often involve maximizing a measure of how sensitive is a given analysis to an hypothesis with respect to another hypothesis; the latter is referred to as "null" hypothesis and in a frequentist framework is tested against the former, which is referred to as "alternative" hypothesis.
In most cases, it is desirable to fully compute the expected frequentist...
We revisit rare radiative leptonic decays B_(s,d) → γee and B_(s,d) → γμμ in the standardmodel and provide the updated estimates for various differential distributions (the branching ratios, the forward-backward asymmetry, and Rμ=e, the ratio of the differential distribution for muons over electrons in the final state). The new ingredients of this work compared to the existing theoretical...
We discuss the case that GW170817 may not have been the merger of a neutron star (NS) with another neutron star, but rather with a hybrid star (HS) possessing a quark matter core, or even a HS-HS merger, and the implications for the equation of state of dense matter at supersaturation densities.
References:
[1] D. Blaschke & N. Chamel, "Phases of dense matter in compact stars", Chapter 7 of...
I will present recent lattice QCD calculations for the pion form factors and quasi parton distributions using partially quenched calculations with HYP smeared Wilson quarks in the valance sector and highly improved staggered quarks in the sea. The calculations are performed at two lattice spacings a=0.06fm and a=0.04fm.
In this talk I will present our strategy for a fully non-perturbative determination of the equation of state (EoS) of QCD from low (T~100 MeV), up to very high temperature (T~100 GeV). The key ingredient for such determination is the lattice formulation of QCD in a moving reference frame. I shall discuss in particular how the set-up allows for a neat determination of the entropy density from...
The spectacular first detection of gravitational waves from the inspiral and merger of a neutron star binary heralded a new era for relativistic astrophysics. This first event - GW170817 - provided interesting constraints on the neutron star radius (through the inferred tidal deformability) and the supranuclear equation of state. In this talk I will present an overview of these results. I will...
We describe the recent theoretical results on |Vxb| determinations, as well as the status and prospective of the related inclusive/exclusive puzzle
or
We analyze the issue of lepton flavor non universality in b -> s l l decays in non-minimal 331 models
I will review recent development in the theoretical descriptions of exclusive
rare B-meson decays. These developments have the potential to remove one source of
theoretical systematic uncertainties, which are presently the biggest roadblock
to our understanding of the present b→sℓℓ anomalies.
Much effort has been expended in deconstructing deep neural networks, that is, in trying to understand their internal representations of data. For example, understanding what convolutional neural networks are doing layer by layer has been the focus of much research. I argue that this effort is largely misplaced. Of far greater importance, in my view, is understanding what these functions...
One of the most celebrated features of QCD is the asymptotic freedom that allows calculations of strong interaction with a perturbative method when the momentum transferred is sufficiently large. The non perturbative regime, however, remains veiled to {\it ab initio} calculations, and it is expected that the large amount of data made available by high energy experiments will give some insight...
We analyze the role of high spin hadronic states in the correlation functions of conserved charges such as baryon and electric charge and strangeness at finite temperature. The corresponding integrated quantities correspond to (global) thermal fluctuations and their related susceptibilities are well known from lattice QCD. At the local level we conjecture an interesting duality between the...
We study the $C=1$, $S=-2$, $I=0$ sector, where five $\Omega_c$ states have been recently observed by the LHCb Collaboration [1]. In Ref. [2] a unitarized meson-baryon model was solved by adopting a one-subtraction renormalization scheme taking, as bare meson-baryon interaction, an extended Weinberg-Tomozawa interaction consistent with both chiral and heavy-quark spin symmetries. This ${\rm...
The LHCb collaboration has measured several observables in the B sector which show consistent deviations from the Standard Model predictions. B decay anomalies are mainly related to lepton flavour universality and angular observables in flavour-changing-neutral-current transitions. In this talk I will present recent results which are key to enlighten new physics scenarios
Upcoming sky surveys require large-volume, high-quality simulated extra-galactic catalogs for such diverse tasks as investigating various data-analysis strategies, understanding and mitigating systematic errors, developing and testing analysis pipelines, and studying observing strategies. In order to prepare adequately for the rich and complex datasets to be delivered by these surveys, the...
Conformal perturbation is a powerful tool to describe the behavior of statistical mechanics models and quantum field theories in the vicinity of a critical point. It was widely used in the past to describe two dimensional models and has been recently extended, thanks to the remarkable results of the bootstrap approach, also to three dimensional models. We show here that it can be also used to...
In the recent years COMPASS at CERN has started to investigate the
proton structure using exclusive reactions like Deeply Virtual Compton
Scattering (DVCS), where high energy muons are scattered off a hydrogen
target. This reaction allows to access Generalised Parton Distributions
and thus the 3-dimensional structure of the proton. From a pilot
measurement in 2012 first results were...
Experiments on neutrinos are very challenging due to the usual collection of very low number of events, the huge and sometime unknown systematics, and the sparse experimental techniques with the corresponding critical assembling of the measurements. All these characteristics point to the necessity of robust, controlled and well established data analyses. Unfortunately, the neutrino community...
Neutron star mergers provide a great opportunity to gather multi-messenger observational information about nuclear matter at high density and moderate temperature. Numerical simulations of mergers are an essential tool for exploiting this opportunity. However, up to now such simulations have generally not included the effects of transport or dissipation, and have focused on measuring the...
We discuss the dynamics and phases of a large class of chiral varieties of QCD. We find that the requirement of the correct realization of chiral symmetries in the infrared is sometimes so strong that it virtually determines the dynamics and phase of the system. In the models considered no gauge-invariant bi-fermion condensates exist, and yet in most cases the assumption of confinement and...
Hadron spectroscopy is a well known powerful tool to study the properties of confinement and the nature of strong interactions. Electro- and photoproduction reactions were never extensively exploited in the past due to the lack of beams of sufficient intensity and momentum resolution. However, a new generation of experiments started recently their operations at Jefferson Lab, exploiting the...
In the collision of nuclei at high energies the produced matter reinteracts and form a plasma which ultimately equilibrates and exhibits collective hydrodynamic flow. While a general theory of the equilibration process has been outlined previously, there were no practical frameworks to smoothly connect the early gluon production in classical field simulations with hydrodynamic simulations of...
In this talk, we will describe the latest additions to the Toolkit for Multivariate Analysis (TMVA), the machine learning package integrated into the ROOT framework. In particular, we will focus on the new deep learning module that contains robust fully-connected, convolutional and recurrent deep neural networks implemented on CPU and GPU architectures. We will present performance of these new...
EDM of the nucleon, whether observed or further constrained, can be traced back to various CP-violating quark and gluon effective interactions. In order to constrain these effective interactions and, subsequently, the extensions of the Standard Model, nonperturbative calculations of nucleon structure are necessary. Low-energy theories and nucleon models provide ballpark estimates for the nEDM...
In this talk, I will present the first set of next-to-next-to-leading order (NNLO) fragmentation functions (FFs) describing the production of charmed-meson $D^{*}$ from partons [Phys.Rev. D97 (2018) no.7, 074014]. Exploiting the universality and scaling violations of FFs, we extract the NLO and NNLO FFs through a global fit to all relevant data sets from single-inclusive $e^+e^-$ annihilation....
Multiparticle production is studied experimentally and theoretically in QCD that describes interactions in the language of quarks and gluons. In the experiment the real hadrons are registered. For transfer from quarks and gluons to observed hadrons various phenomenological models are used.
In order to describe the high multiplicity region, we have developed a gluon dominance model (GDM). It...
Due to absence of expansion transverse to the beam direction, Bjorken flow is unable to describe certain observables in heavy ion collisions such as transverse momentum spectra of final hadrons. This caveat has motivated introduction of analytical relativistic hydrodynamics(RH) solutions with transverse expansion, in particular 3+1 self-similar and Gubser flows. Inspired by recently found...
Bayesian Gaussian Process Optimization [1,2,3] can be considered as a method of the determination of the model parameters, based on the experimental data. In the range of soft QCD physics, the processes of hadron and nuclear interactions require using phenomenological models containing many parameters. In order to minimize the computation time, the model predictions can be parameterized using...
We study the recently discovered mixed discrete-chiral/center-symmetry (0-form/1-form) 't Hooft anomalies, which give new nontrivial consistency conditions that the IR dynamics of a strongly coupled QFT should obey. We use the simplest QFT example where such anomalies are present, the massless Schwinger model with charge-q fermions, to simply elucidate how they appear. We show that the...
In the last decade, charmed and bottom meson spectroscopy have seen great success in experimental sector. Experiments like LHCb, Babar etc are providing many new states which are being added to their spectroscopy. Newly predicted states like Ds(3040), Ds(2700), Ds(2860) and many more still need to be assigned their proper place in the spectroscopy. So we studied the decay constant and the...
The quest for a non-zero electric dipole moment (EDM) in a non-degenerate system such as the neutron is a powerful way to search for physics beyond the standard model in the CP violation framework, complementary to LHC based experiments. So far, no evidence for such an intrinsic property was observed, neither for the neutron nor for any other system. After a long and successful data taking at...
The plans for the second Run of the LHC changes the focus in the Higgs sector from searches to precision measurements. Effective Lagrangians can be used for parameterisation. A signal morphing method is developed to take all parameters into account simultaneously and model interference effects. It provides a continues description of arbitrary physical signal observables such as cross sections...
Among the parameters of QCD is one that results in CP violation when
non-vanishing. This is closely related to possible quark mass terms.
It is conventionally interpreted in terms of gauge field topology or
alternatively in terms of real chiral eigenvalues of the Dirac
operator. There is no experimental evidence for this parameter having
a non-zero value, a puzzle for theories involving unification.
We present recent experimental results for e+e− annihilation into hadrons below 2 GeV obtained with the SND detector at the VEPP-2000 collider. The analyses are based on data collected in the detector runs from 2010 to 2017 years.
A new framework for relativistic fluid dynamics of particles with spin 1/2 is presented. It is based on the conservation laws for baryon number, energy and momentum, and angular momentum. The conservation laws lead to hydrodynamic equations for the charge density, local temperature, and fluid velocity, as well as for the spin polarization tensor. The resulting set of differential equations...
The appearance of strangeness in compact stars is uncertain in both, the nuclear and quark matter sector. While hyperons are sensitive to coupling constants, the threshold for the appearance of strange quark matter depends on both, coupling constants in the entire light quark sector and the way one models the deconfinement phase transition.
I will present how this can lead to ambiguities which...
Tetraquark properties will be examined in the limit of large
N_c of color in QCD. The qualitative differences between molecular
and compact teraquarks will be outlined. Consequences of
the possible existence of compact tetraquarks will be analyzed and
shown to lead to upper bounds in the N_c-behavior of their decay
widths. Open questions on theoretical grounds, related to the
dynamics of...
I will discuss determination of $\alpha_s$ from the comparison of the lattice results on the static quark anti-quark static energy at short distances to EFT based weak coupling calculations. I addition I will present results on $\alpha_s$ from the moment of quarkonium correlators.
The Belle II experiment, now operating at the KEK laboratory in Japan, is a substantial upgrade of both the Belle detector and the KEKB $e^+ e^-$accelerator. It aims to collect 50 times more data than existing B-Factory samples. Belle II is uniquely capable to study the so-called "XYZ" particles: heavy exotic hadrons consisting of more than three quarks. First discovered by Belle, these now...
We first review transverse-momentum dependent (TMD) gluon distributions at small $x$ and their relation to unintegrated gluon distributions in the Color Glass Condensate (CGC) theory. We then explore several applications of this connection relevant for studying gluon saturation at small $x$. For instance, based on the equivalence between the TMD factorization approach and the CGC cross section...
Recent statistical evaluation for High-Energy Physics measurements, in particular those at the Large Hadron Collider, require careful evaluation of many sources of systematic uncertainties at the same time. While the fundamental aspects of the statistical treatment are now consolidated, both using a frequentist or a Bayesian approach, the management of many sources of uncertainties and their...
Approaches to the sign problem based on the density of states have been recently revived by the introduction of the LLR algorithm, which allows us to compute the density of states itself with exponential error reduction. In this work, after a review of the generalities of the method, we show recent results for the Bose gas in four dimensions, focussing on the identification of possible...
The effective field theory of the light $0^{++}$ scalar is discussed in an important near-conformal strongly coupled BSM gauge theory and its lattice simulations. Relevant for the composite Higgs, two distinct scenarios are analyzed for the emergent light scalar as composite $\sigma$-particle of chiral symmetry breaking or the dilaton of conformal symmetry breaking.
In this talk I review recent progress in the determination of the parton distribution functions (PDFs) of the proton, with emphasis on the applications for precision phenomenology and of searches for new physics beyond the Standard Model at the Large Hadron Collider (LHC). I discuss the number of recent developements such as the use of novel observables such as top quark pair production and...
Chiral perturbation theory (ChPT) and the $1/N_c$ expansion provide systematic frameworks in investigating the strong interactions at low energy. A combined framework of both approaches has been developed and applied for baryons with three light-quark-flavors. The small scale expansion of the combined approach is identified as the $\xi$-expansion, in which the power counting of $1/N_c$ and...
During the last years it has become possible to address the nuclear liquid gas transition in QCD directly for
sufficiently heavy quarks, where combined strong coupling and hopping expansions are convergent. In this
contribution we study the Nc-dependence of the liquid gas transition and the equation of state of baryonic
matter. We find the transition to become more strongly first order with...
We discuss an extension of chiral perturbation theory where we include an isosinglet scalar in the Lagrangian. The dynamical effects from the scalar state is of phenomenological relevance in theories where the mass of the isosinglet scalar is comparable to the mass of the pseudo-Goldstone bosons. This near-degeneracy of states is for example observed in certain near-conformal BSM models. From...
Different situations appearing in HEP involve the calculation of CI for linear combinations of observations that follow a Poisson distribution. Although apparently a simple problem, no precise methods exist unless asymptotic approximations can be assumed. We propose different alternatives beyond the error propagation of Gaussian errors and estimate their performance in some common examples.
We present non-perturbative first-principle results for quark-, gluon- and meson 1PI correlation functions of two-flavour Landau-gauge QCD in the vacuum [1] and Yang-Mills theory at finite temperature [2]. These correlation functions carry the full information about the theory and their connection to physical observables is discussed. We confront our results for the correlation functions with...
Reaching next-to-leading order accuracy in perturbative calculations of particle production in QCD at high energy is essential for reliable phenomenological applications. In recent years, the Color Glass Condensate effective theory (the natural framework for such calculations) has indeed been promoted to NLO accuracy. However, the first NLO calculation of single-inclusive hadron production met...
In this talk I will explain how to obtain the perturbative NNNLO heavy quarkonium spectrum for equal and different masses. This computation allows to determine the charm and bottom quark masses from the bottomonium, charmonium and $B_c$ systems. The use of the renormalon subtracted scheme, provides control over the divergence of the perturbative series due to the pole mass renormalon. On top...
Chiral effective field theory has been developed into a reliable, qiantitative approach to low-energy few- and many-nucleon systems. I will review the current status of nuclear forces in this framework and discuss selected applications to light nuclei and nuclear matter. Special emphasis will be given to uncertainty quantification.
I discuss some features of entanglement between the fast valence modes and the soft gluons in high energy hadronic scattering. Production entropy for the ensemble of events as well as for a single event is discussed.
I review the status of the resummation of large logarithms in the spectrum of heavy quarkonium. The seaked precision is NNNLL. Special emphasis is put in P-wave states for which complete results to this order are presented.
I discuss using a generalized linear sigma model as an effective field theory (EFT) to describe nearly conformal gauge theories at low energies.
The work is motivated by recent lattice studies of gauge theories near the conformal window, which have shown that the lightest flavor-singlet scalar state in the spectrum ($\sigma$) can be much lighter than the vector state ($\rho$) and nearly...
First I will review significant performance gains that were reached for ongoing experiments by applying deep learning techniques classification tasks in jet physics. I will also review how to extend such methods to for cases where we do not have unique labels, but where the labels in simulation themselves are already a production of a random process of simulation. Finally, if times allow I...
We studied the transition form factor involved in pseudoscalar meson ($\pi$,$\eta$,$\eta$') decays into two virtual photons by means of a chiral-invariant Lagrangian, considering the lowest-lying multiplet of vector and pseudoscalar resonances. Accounting for $U(3)$ breaking effects, we give the most general corrections of order $m_P^2$ to the form factor. Most parameters are fixed requiring...
Z3 gauge theory mimics certain properties of QCD and might even have a quantitative link when the Z3 physical degrees of freedom are identified with the core of the so-called centre vortices of QCD. In particular, the Z3 theory confines static triality charges. In this talk, I will consider Z3 gauge theory with Z3 dynamical matter. A finite chemical potential is introduced to study this theory...
The perturbative accuracy for bottomonium observables has recently been extended to next-to-next-to-next-to-leading order. Assuming the hierarchy $\Lambda_\text{QCD}\ll m_bv^2$ holds, non-perturbative corrections take the form of local condensates. I determine higher-order corrections in this approach and assess its validity by studying the convergence of the series. In particular, the...
We briefly summarize current experimental and theoretical results on the two important processes of the low energy hadron physics involving neutral pions: the Dalitz decay of $\pi^0$ and the rare decay $\pi^0\to e^+e^-$. As novel results we present the complete set of radiative corrections to the Dalitz decays $\eta^{(\prime)}\to\ell^+\ell^-\gamma$ beyond the soft-photon approximation, i.e....
I will discuss recent lattice QCD calculations that constrain aspects of neutrino-nucleon and neutrino-nucleus interactions. In particular, I will show results for axial charges and form factors of the nucleon and of nuclei, constraints of tritium beta decay, and input for neutrinoful and neutrinoless double beta decay.
The precision determination of the parton distribution functions (PDFs) of the proton is a central component for the precision phenomenology program at the Large Hadron Collider (LHC). Pinning down the quark and gluon structure of the proton strengthens a number of LHC cornerstone measurements such as the characterisation of the Higgs sector and searches for high-mass bSM resonances. In this...
We investigate non-abelian Higgs theory in a constant strong magnetic field, where the lowest-Landau-level approximation can be used. At a critical magnetic value $eB=m^2$, the off-diagonal charged vector fields behave as one-dimensional massless fields and give a strong correlation along the magnetic direction, which may lead a new type of confinement caused by off-diagonal vector fields.
Whether the U(2N) symmetry of Dirac fermions in 2+1 space-time dimensions is spontaneously broken by pair condensation once interactions are present is an important problem in non-perturbative quantum field theory. Here I focus on the Thirring model, whose interaction is a current-current contact term, using numerical simulations of a lattice model formulated with domain wall fermions - it has...
In recent years, there have been important advances in understanding the far-from-equilibrium dynamics in gauge and scalar field theories. For non-Abelian gauge systems, the combination of different methods led to the development of a consistent weak-coupling thermalization picture in ultrarelativistic heavy-ion collisions, from the initial Glasma state to the onset of hydrodynamics, and the...
The typical energy scale of heavy hadron spectroscopy makes the system accessible to perturbative calculations in terms of non-relativistic QCD. Within NRQCD the predictions of heavy quarkonium energy levels rely on the accurate description of the static QCD potential $V_{\rm QCD}(r)$. Most recent calculations computed the energy levels of the lower-lying bottomonium states up to...
We determine the charm quark mass mc(mc) from QCD sum rules of moments of the vector current correlator calculated in perturbative QCD. Only experimental data for the charm resonances below the continuum threshold are needed in our approach, while the continuum contribution is determined by requiring self-consistency between various sum rules, including the one for the zeroth moment. Existing...
We study the electroweak phase transition within a 5-dim warped model
including a scalar potential with an exponential behavior, and strong
back-reaction over the metric, in the infrared. By means of a novel
treatment of the superpotential formalism, we explore parameter
regions that were previously inaccessible. We find that for large
values of the t’Hooft parameter the holographic phase...
The properties of the form factors describing the rare CP conserving decay modes $K \to \pi l^+ l^-$, $(K,\pi) = (K^\pm,\pi^\pm)$ or $(K_S,\pi^0)$, $l=e,\mu$, are addressed. First, a full two-loop representation of the corresponding form factors in the low-energy expansion is constructed. Next, the contribution from pi-pi intermediate states is considered from a dispersive point of view....
Hard scattered quarks and gluons have been used extensively as multi-scale probes of the strongly interacting medium produced in relativistic heavy ion collisions. The high statistics data recorded in the Large Hadron Collider and large transverse momentum reach due to the high nucleon-nucleon center-of-mass energy have opened a new era for the understanding of the mechanism of parton-medium...
A possible explanation of dark matter is the existence of an unobserved massive particle. The mass range and the interaction rate with ordinary matter extend over several orders of magnitude. Different detector technologies will be required in order to reach the necessary sensitivity. The CRESST III experiment (Cryogenic Rare Event Search with Superconducting Thermometers) is best suited to...
Data Quality plays an important role in many high-energy physics experiments, e.g. the ALICE experiment at the Large Hadron Collider (LHC), CERN. Currently used methods for quality assurance problems such as quality label assignment or particle identification, rely heavily on human expert judgments and complex computations. Those tasks, however, can be easily addressed by modern machine...
To establish the widely accepted dual superconductivity picture for explaining quark confinement, a reformulated version of $SU(N)$ Yang-Mills theory, which is based on the Cho-Faddeev-Niemi decomposition, has been recently developed. However, from a novel viewpoint, this decomposition is merely considered to be a nonlinear change of variables.
Within this framework, we consider a certain...
This talk considers exotic hadrons containing two heavy quarks (or a heavy quark and a heavy antiquark). It is argued on very general model-indpendent grounds that in the heavy quark limit such exotic hadrons must exist as parametrically narrow states. Moreover, it is shown that there in this limit there will be multiple exotic resonances with the same quantum numbers and that some of these...
We revisit the construction of the composite Higgs models in a context of the bottom-up holographic approach. The soft wall framework is under consideration imposing the translation of the $4D$ global symmetry breaking characteristic to the new strongly interacting sector to the $5D$ bulk. The focus stays on the minimal $SO(5)\to SO(4)$ breaking pattern.
The $5D$ model has a specific form...
A lot of work done in advancing the performance of deep-learning approaches often takes place in the realms of image recognition - many papers use famous benchmark datasets, such as Cifar or Imagenet, to quantify the advantages their idea offers. However it is not always obvious, when reading such papers, whether the concepts presented can also be applied to problems in other domains and still...
We present a formalism based on chiral effective field theory that incorporates all coherent responses relevant for the analysis of direct-detection dark-matter searches. The nuclear response functions are derived, including contributions from one- and two-body nuclear currents as well as interference terms between the different channels. The corresponding structure factors for the isotopes...
Recent developments in the calculation of radiative QED corrections to hadronic weak decays are described and results of numerical simulations presented. A critical discussion of possible future developments will also be given.
I discuss recent results on the relation between the localisation of low-lying Dirac eigenmodes, the restoration of chiral symmetry, and deconfinement in QCD and QCD-like models, providing evidence of a close connection between the three phenomena.
Properties of resonances and excited states near decay thresholds are encoded
in hadronic scattering amplitudes, which can be extracted from the finite volume
spectrum using (extensions of) Lueschers method. We discuss how to reliably
extract the finite volume spectrum above strong-interaction decay thresholds
from lattice QCD simulations. Preliminary results for such spectra in
various frames...
We study the production of vector resonances at the LHC via WZ scattering processes and explore the sensitivities to these resonances for the expected future LHC luminosities. The electroweak chiral Lagrangian and the Inverse Amplitude Method (IAM) are used for analyzing a dynamically generated vector resonance, whose origin would be the (hypothetically strong) self interactions of the...
The Standard Model is currently the most widely accepted physical theory that classifies all known elementary particles and represents three out of the four fundamental forces in the universe. Despite the confirmation of the model, there is a need for its generalization or for the development of a new theory, able to complete our knowledge of the Universe. For this purpose, High Energy...
Quark masses are fundamental parameters of the standard
model that are key for our understanding of the natural laws. Light quark masses give valuable information on the flavor structure of natural laws and on the nature of spontaneous chiral symmetry breaking. The masses of the heavy charm and bottom quark play a key role in the theoretical predictions of the Higgs boson decay rates. Due...
While many properties of the vector charmonium first excitations are yet to be determined, enhancements at unexpected energies are intriguing, alias the $Y$ states. In order to understand the naturally unquenched mesonic line-shapes, the influence of the most relevant hadronic decay channels must be taken into account. Within an unitary effective approach we present results where mesonic loops...
We perform a high precision measurement of the static quark-antiquark potential in three-dimensional SU(N) gauge theory with N=2 to 6. The results are compared to the effective string theory for the QCD flux tube and we obtain continuum limit results for the string tension and the non-universal leading order boundary coefficient, including an extensive analysis of all types of systematic...
Differential cross section measurement in experimental particle physics are smeared by the finite resolution of particle detectors. Using the smeared observations to infer the true particle-level spectrum is an ill-posed inverse problem, which is typically referred to as unfolding or unsmearing. In this talk, I will first give an overview of the statistical techniques that are currently used...
For decades, high-energy physics (HEP) had been on the forefront of big data technology, developing techniques to explore and analyze datasets too large for memory that were revolutionary when they appeared in other fields years later. Today, that dominance is ending, and I argue that it's a good thing. The rise of web-scale datasets and high-frequency trading has interested the commercial...
We report the first observation of the parity-violating $2.2$ MeV gamma-ray asymmetry $A^{np}_{\gamma}$, in neutron-proton capture using polarized cold neutrons incident on a liquid parahydrogen target, at the Spallation Neutron Source at Oak Ridge National Laboratory. The asymmetry isolates the long-range component of the hadronic weak interaction, corresponding to the $ \Delta I = 1$, $^3S_1...
We will report on recent progress in the determination of spectral and transport properties of heavy quarks. Combining continuum extrapolated correlation functions in a pure SU(3) plasma and spectral reconstructions constrained by phenomenological and perturbative input, we study thermal modifications of quarkonium spectra and improve the determination of heavy quark diffusion coefficients.
We report about an ongoing lattice field theory project concerned with static hybrid mesons. In particular we study the structure of hybrid static potential flux tubes in Lattice Yang-Mills-theory by computing the square of the chromoelectric and chromomagnetic field strength components for several hybrid static potential quantum numbers. We find clear indications that the gluonic distribution...
The light pseudoscalar meson decays provide a unique laboratory to test fundamental QCD symmetries at low energies. A comprehensive Primakoff experimental program at Jefferson Laboratory (JLab) is aimed at gathering high precision measurements of the two-photon decay widths and the transition form factors (at low four-momentum transfer squares) of π0, η and η′ via the Primakoff effect. The results...
We present predictions for the prompt-neutrino flux arising from the decay of charmed mesons and baryons produced by the interactions of high-energy cosmic rays in the Earth's atmosphere, making use of a QCD approach on the basis of the general-mass variable-flavor-number scheme for the description of charm hadroproduction at NLO, complemented by a consistent set of fragmentation functions. We...
I will review insights into confinement in supersymmetric theories, and discuss some strongly coupled beyond the standard model scenarios.
The strong CP problem of QCD can be solved via the Peccei-Quinn mechanism, which results in not-yet observed particles, called axions. They are natural dark matter candidates. Assuming that all dark matter is axionic, the theory can predict the mass of the axion providing useful hint for experimental searches. I review hier recent theory developments aiming to put such predictions on a solid footing.
I will review recent developments in the theoretical description and understanding of multi-particle correlations in collisions of small projectiles (p/d/3He) with heavy nuclei (Au, Pb), as well as in proton+proton collisions. A main question is, whether the physical processes responsible for the observed long range rapidity correlations and their azimuthal structure are the same in small...
I will review recent results obtained within the Hamiltonian approach to QCD in Coulomb gauge. The focus will be on the quark sector at finite temperatures. The temperature is introduced by compactifying a spatial dimension. The quark gap equation is solved numerically at finite temperatures. I will also report on preliminary studies of the effective potential of the Polyakov loop at 2-loop level.
COMPASS is a multi-purpose fixed-target experiment at CERN aimed at studying the structure and spectrum of hadrons. The two-stage spectrometer has a good acceptance over a wide kinematic range and is thus able to measure a wide range of reactions. Light mesons are studied with a negative hadron beam (mostly $\pi^-$) with a momentum of $190~\text{GeV}/c$.
The light-meson spectrum is...
In this talk, I will focus on an exceptional way of doing data-driven research employing networked community. Many examples of collaboration with the data-science community within competitions organised on Kaggle or Coda Lab platforms usually get limited by restrictions on those platforms. Common metrics do not necessarily correspond to the goal of the original research. Constraints imposed...
We propose a new view of crossover between nuclear and quark matter. There are already some theoretical discussions on a percolation picture to describe how quark degrees of freedom would appear. In such a picture of classical percolation, however, it was overlooked that nuclear interactions also contribute to quark mobility, and the physical mechanism to make quark wave-functions localized...
The talk will describe the g-2 experiment based at Fermilab.
As the experiment enters an exciting period of data taking
and analysis, the current status and future prospects will be
highlighted.
In recent years, a new class of exotic charmonium-like states, also referred to as XYZ states, have been discovered. Being incompatible with the simple quark-antiquark model, they are candidates for non-standard hadrons such as tetraquarks, meson molecules, and hybrids. The BESIII experiment operating at the electron-positron collider BEPCII at IHEP (Beijing) has accumulated a large amount of...
In most studies of the QCD phase structure at nonzero temperature and density it is assumed that the chiral condensate is constant in space. Allowing for spatially modulated condensates on the other hand, it was found in various model calculations that in certain regions of the phase diagram such inhomogeneous condensates are favored over homogeneous ones. For instance it was shown that in a...
We present an effective field theory calculation of the lower lying heavy hybrid spectrum, which includes mixing with heavy quarkonium states as a novel feature. Spin zero (one) hybrids turn out to mix with spin one (zero) quarkonia, which is intrumental to explain apparent spin symmetry violating decays of certain XYZ resonances that have been identified as hybrid states. We also present some...
QCD is not supersymmetrical in the traditional sense -- the QCD Lagrangian is based on quark and gluonic fields, not squarks nor gluinos. However, its hadronic eigensolutions conform to a representation of superconformal algebra, reflecting the underlying conformal symmetry of chiral QCD and its Pauli matrix representation. The eigensolutions of superconformal algebra provide a unified...
Complex machine learning tools, such as deep neural networks and gradient boosting algorithms, are increasingly being used to construct powerful discriminative features for High Energy Physics analyses. These methods are typically trained with simulated or auxiliary data samples by optimising some classification or regression surrogate objective. The learned feature representations are then...
The anomalous magnetic moment of the muon is one of the most
accurately measured quantities in particle physics and one of the very
few to exhibit a significant discrepancy with respect to its Standard
Model determination. The origin of this discrepancy is unknown. Forthcoming experimental results which are expected to improve the already
impressive accuracy of 0.54 parts per million reached...
We present the correct form of the nonequilibrium viscous correction to the phase space density in the relaxation time approximation that properly takes into account the space-time dependence of the thermal mass. We also investigate the impact the correction has on the bulk viscosity. This correction automatically satisfies the Landau matching condition and energy-momentum conservation. It...
It is generally believed that systems with two fermion species that form Cooper pairs form a neutral state, where the number densities of the two fermion species are equal. This belief is based on mean field calculations with a zero-range contact interaction. We have put this claim to the test using a Yukawa model, where the interaction range is finite. The results of this study suggest that...
We study tetraquark resonances for a pair of static quarks $\bar{b}\bar{b}$ in presence of two light quarks $ud$ based on lattice QCD potentials. The system is treated in the Born-Oppenheimer approximation and we use the emergent wave method. We focus on the isospin $I=0$ channel but take different angular momenta $l$ of the heavy quarks $\bar{b}\bar{b}$ into account. Further calculations have...
We quantify the importance of dynamical spin effects in the holographic light-front wavefunctions of the pion, kaon, η and η′. Using a universal AdS/QCD scale and constituent quark masses, we find that such effects are maximal in the pion where they lead to an excellent simultaneous description of a wide range of data: the decay constant, charge radius, spacelike EM and transition form...
Different evaluation metrics for binary classifiers are appropriate to different scientific domains and even to different problems within the same domain. This presentation discusses the evaluation of binary classifiers in experimental high-energy physics, and in particular those used for the discrimination of signal and background events. In the introductory part of the talk, the general...
We discuss possible definitions of the Faddeev-Popov
matrix for the minimal linear covariant gauge on the
lattice and present preliminary results for the ghost
propagator.
We present energy spectra of various tetraquark states with one or more heavy quarks using lattice quantum chromodynamics. These calculations are performed on
$N_f=2+1+1$ MILC ensembles at lattice spacings ~ 0.12, 0.09 and 0.06
fm. A relativistic action with overlap fermions is employed for the
light and charm quarks while a non-relativistic action with
non-perturbatively improved coefficients...
We discuss the fixed-point structure and symmetry breaking patterns of hot and dense QCD. Our study particularly addresses the phase structure at low temperature and large quark chemical potential, a region where the application of fully first-principles approaches is currently difficult at best. To this end, we employ a Fierz-complete set of four-quark interactions which are dynamically...
Recent advancements in multi-parameter model-to-data comparison have provided notable constraints on the temperature dependence of the shear viscosity over entropy density ratio $\eta/s$ in the matter produced in the Pb+Pb collisions at the LHC. The results of the Bayesian analysis with a flexible initial state parametrization [1,2] support a linear temperature dependence of $\eta/s$ found in...
The dynamical cancellation of the vacuum energy of the QCD sector in the infrared regime is a relevant problem for both particle physics and cosmology. We find an argument related to the existence of a Z_2-symmetry for the renormalization group flow derived from the bare Yang-Mills Lagrangian, and show that the cancellation of the vacuum energy may arise motivated both from the renormalization...
In this talk I will discuss various aspects of pion condensation at finite
temperature and density. At T=0, the phase diagram will be mapped
out in the mu_I-mu_B plane, and we
will discuss the competition between an inhomogeneous chiral condensate and
a pion condensate. At finite T, we map out the phase diagram in the
mu_I-T plane focusing on the deconfinement and chiral transitions as...
In this work, we examine the flavour-dependence of dynamical chiral symmetry
breaking (DCSB) due to the effect of different model kernels in the gap equation.
For that, we have computed the quark’s sigma term and its ratio to the
Euclidean constituent mass, that computes the DCSB contribution.
The CMD-3 detector is taking data at the VEPP-2000 e+e-
collider (BINP, Novosibirsk, Russia). The CMD-3
is the general purpose particle magnetic (1.3 T) detector, equipped with
the tracking system, two crystal (CSI and BGO) calorimeters, liquid Xe
calorimeter, TOF and muon systems. The main goal of experiments with CMD-3
is the measurement of the cross-sections and dynamics of the...
It is fairly well established that X(4260) does not correspond, regarding its mass and transition properties, to a conventional c-cbar state of the type provided for example by the Cornell [1] or the Godfrey-Isgur [2] models. This has motivated the development of other descriptions involving Fock space components (tetraquarks, meson molecules, hybrids...) different from c-cbar (see for example...
We have studied the superconductor-insulator transition (SIT) in strongly disordered superconducting films and Josephson junction arrays (JJA) as a paradigm example example in which quantum synchronization gives rise to new phases of matter in d=2 and d=3 spatial dimensions.
In fact recent experimental results have shown that at absolute zero electrons can form quantum coherent states...
The existence of a mechanism with QCD to confine quarks and gluons to the interior of hadrons has long been accepted empirically. To explore the properties required for this confinement we present a field-strength description for a simple extended system of SU(2) charges with spherical symmetry and then impose confining boundary conditions on the time-independent Yang-Mills-Maxwell equations....
We study the thermodynamics of hadronic matter using the hadron resonance gas model where the repulsive interactions between baryons are modeled using the mean field approach.
We have shown [1] that repulsive interactions are especially important when considering the higher order fluctuations. We now extend the treatment of [1] to cover not only ground state baryons but heavier resonances...
The first measurements of the production of lambda, sigma, cascade, and omega hyperons at large timelike momentum transfers of 13.6, 14.2, and 17.4 GeV^2 have been made using e+e- annihilation data taken at the CESER electron-positron collider at Cornell using the CLEOc detector. The measurements reveal interesting features of hyperon production systematics and timelike form factors, and...
Lund diagrams, a representation of the phase space within jets, have long been used in discussing parton showers and resummations. I will point out that they can also serve as a powerful tool for experimentally characterising the radiation pattern within jets. I will briefly comment on some of their analytical properties and highlight their scope for constraining Monte Carlo simulations. I...
Recent developments of anomaly matching allows us to study the new nonperturbative aspects of various gauge theories. In this talk, I will show that there is a new 't Hooft anomaly for QCD with massless quarks containing the two-form gauge fields. This will give new constraints on the possible chiral symmetry breakings, and I will revisit the Stern phase (chiral symmetry broken phase without...
Recent developments of experimental techniques have given us unprecedented opportunities of studying topological insulators and emergent Dirac and chiral fermions in high dimensions, while some of the dimensions are "synthetic", in the sense that the effective lattice momenta along these synthetic dimensions are controllable periodic tuning parameters. We study interaction effects on...
In this talk I shall discuss how the S-matrix formalism can be applied to study the thermal properties of interacting hadrons.
The approach allows a consistent treatment of broad resonances and purely repulsive channels, while correctly implementing the constraints from the chiral perturbation theory. This provides a useful framework for identifying the limitations of the Hadron Resonance...
The high energy scale of the LHC and the large associated Lorentz boost of hadronically decaying massive particles has resulted in the creation of a new approach to jet identification. Jet substructure, or the use of angular and energy distributions within jets, has proven to be a powerful means of differentiating between hadronic decays of massive particles and QCD multijets production. ...
The presentation will provide insight into the treatment of statistical problems by particle physicists, which is commonly driven by practical considerations much more than mathematical reasoning. Common pitfalls and their origin will be discussed using real life (but anonymized) examples, touching on topics such as unfolding and limit setting.
Recent years have seen significantly increased interest in hadron spectroscopy, triggered primarily by the experimental discovery of unconventional states. However, experimental data alone is not always sufficient to discern the nature and structure of a given state. In this talk, I discuss a class of observables that are experimentally inaccessible but can be accessed
via lattice QCD. I will...
Recent studies suggest that important contributions to the CME originate in the pre-equilibrium phase of a collision. While real-time lattice simulations can be utilized to understand the dynamics of anomalous effects in the earliest stages of a collision, quantitative predictions of experimental signatures are only feasible once the subsequent transport of the messengers of the CME through...
A model based on CGC/Saturation approach and the BFKL Pomeron was originally constructed to describe soft interactions at LHC energies [reference (a)]. It has now been extended to also describe hard interactions at HERA energies [reference (b)]. The model also provides a good description of inclusive production, rapidity and angular correlations over a wide range of energies. We outline the...
The nature of chiral symmetry restoration and the identification of its correct pattern in terms of $O(4)$ and $U(1)_A$ symmetries are central problems for our present understanding of the QCD phase diagram, currently explored in lattice simulations and heavy-ion collisions. We will present a theoretical analysis based on Ward Identities for the full scalar/pseudoscalar $U(3)$ meson...
GPUs represent one of the most sophisticated and versatile parallel
computing architectures that have recently entered in the HEP field.
GooFit is an open source tool interfacing ROOT/RooFit to the CUDA
platform that allows to manipulate probability density functions and
perform fitting tasks. The computing capabilities of GPUs with
respect to traditional CPU cores have been explored with...
The $q\bar q s\bar s$ and $q\bar q c\bar c$ $J^{PC}=1^{--}$ 4-body systems are investigated by a simplified quark cluster model, where the 14 relevant channels are coupled. In each of the systems, one or more poles have been found. For the $q\bar q c\bar c$, a pole appears close to the thresholds and its width is found to be small. The poles found in the $q\bar q s\bar s$ have rather larger...
We explore the validity of vector meson dominance in the radiative decay of the $b_1(1235)$ meson. In order to explain the violation of the vector meson dominance hypothesis in this decay process, we investigate a model where the $b_1$ meson strongly couples with the local current in tensor bilinear representation. The tensor representation is investigated in the framework of the operator...
I will report on our studies of strongly correlated fermions on the hexagonal lattice with Hybrid Monte-Carlo simulations. In particular, we have determined the phase diagram in on-site U and nearest-neighbor repulsion V of the extended Hubbard model in the region V < U/3 where it can be simulated without a fermion sign problem. Several important algorithmic improvements, such as the analogue...
At present large data samples were accumulated at the BESIII detector, operated in the upgraded electron positron collider in Beijing (BEPC-II), in the energy region of 2.0-4.6 GeV, which provides a super opportunity in the study of light hadron spectra and charmonium(-like) decays. We summarize the isospin violations in recent BESIII analyses, which are divided into three categories: isospin...
We study $4$-dimensional SQCD with gauge group $SU(N_c)$ and $N_f$ flavors of chiral super-multiplets on the lattice. We perform extensive calculations of matrix elements and renormalization factors of composite operators in Perturbation Theory. In particular, we compute the renormalization factors of quark and squark bilinears, as well as their mixing at the quantum level with gluino and...
Summary Section H
I will discuss the current state of perturbation theory of the cold and dense QCD thermodynamics. Alongside, I explain a method of handling the infrared degrees of freedom of the theory using Hard Thermal Loop approximations, suitable for the computation of the non-analytic terms of the pressure. By making use of this framework, I will present the computation of a new term, the leading,...
In this talk I will review the recent analyses and other activities carried
out by the JPAC collaboration. In particular, the phenomenological analysis of
the COMPASS data on $\eta \pi$ and $\eta' \pi$ partial waves, with the goal of
determining in a robust way the pole position of the hybrid meson $\pi_1(1400)$,
as well as the ordinary mesons $a_2(1320)$ and the $a'_2(1700)$
Quantum anomalies give rise to new transport phenomena. In particular a magnetic field can induce an anomalous current via the chiral magnetic effect [1] and a vortex in the relativistic fluid can also induce a current via the chiral vortical effect [2]. The related transport coefficients can be calculated via Kubo formulae [3,4,5]. These effects can be studied in holographic models with...
We analyze the pseudo-Goldstone-boson nature of the lightest pseudoscalar mesons within a framework residing somewhere in between the genuinely Poincaré-covariant Bethe–Salpeter approach to bound states (facing various inherent problems yet to be resolved) and the latter’s extreme instantaneous limit, represented by its three-dimensional reduction due to Salpeter. A promising tool to assess...
The fluctuations of the net electric charge of hadrons, produced in ultrarelativistic heavy ion collisions, were proposed as one of the indicators of the formation of a quark-gluon plasma [1,2]. They also carry important information on the collective dynamical effects in AA collisions [3,4].
Experimentally, they are studied in terms of dynamical fluctuation parameter $\nu_{dyn}$ and the...
Following the work in Ref. http://inspirehep.net/record/1670613, we are investigating the Polyakov loop correlator, singlet and octet quark-antiquark correlators, diquark correlators, and screening masses in 2+1 flavor QCD. We are using the highly improved staggered quark (HISQ) action and several lattice spacings at a wide variety of temperatures.
We include more levels of HYP smearing as...
Complex machine learning tools, such as deep neural networks and gradient boosting algorithms, are increasingly being used to construct powerful discriminative features for High Energy Physics analyses. These methods are typically trained with simulated or auxiliary data samples by optimising some classification or regression surrogate objective. The learned feature representations are then...
We present a model for the QCD structure of hadrons as seen in the dipole picture. The model is based on hot spots -- regions of large gluonic density -- populating the impact parameter space. In our model, the number of hot spots grows with energy and their positions fluctuate event-by-event.
Using this model, we calculate coherent and incoherent photoproduction
of vector mesons off a proton...
The evolution of the multiplicity distribution can be described with the help of master equation.
At the beginning we look at 3rd and 4th factorial moments and their equilibrium values from which central moments and other ratios can be calculated.
Firstly, we study the master equation for the fixed temperature, because we want to know how fast different moments of the multiplicity...
We report on results for the Landau gauge gluon propagator computed from large statistical ensembles and look at the compatibility of the results with the Gribov-Zwanziger tree level prediction for its refined and very refined versions. Our results show that the data is well described by the tree level estimate only up to momenta p ≲1 GeV, while clearly favoring the so-called Refined...
We propose a model-independent method to ascertain the leading valence composition of a hadron: to measure the energy dependence of its production cross section at a fixed angle interval. This E-dependence, by the QCD Brodsky-Farrar counting rules, falls at high energy with a steepness that depends on the leading quark and gluon composition.
We exemplify with a reaction that could help...
We accurately investigate monopole dominance of quark confinement for both quark-antiquark and three-quark systems in SU(3) quenched lattice QCD in the maximally Abelian gauge at beta=5.8 on 16^3*32 with 2000 gauge configurations. We find monopole dominance of the string tension for quark-antiquark and three-quark systems.
The extraction of the order of the thermal transition of QCD at zero chemical potential, with two dynamical flavours of massless quarks, has proven to be a formidably difficult task. A first order region is found in the chiral limit only on coarse lattices and employing unimproved fermion discretisations, but whether it survives in the continuum limit is yet far from being known.
This...
The phase structure of QCD can be explored with functional methods.
The challenge is to devise and solve an appropriate truncation of the corresponding
equations. Here the application to theories similar to QCD but
without the sign problem of lattice methods (QCD-like theories) becomes
useful, as truncations can be tested by comparison to corresponding lattice
results also at nonvanishing...
In order to paint, within a common framework, a comprehensive picture of the description of mesons as quark–antiquark bound states by a Bethe–Salpeter formalism drawing on the outcomes of the Dyson–Schwinger equation for the quark propagator, we complement existing discussions of quarkonia (i.e., same-flavour quark–antiquark bound states) by a thorough investigation of open-flavour mesons...
The critical phenomena of strongly interacting matter are presented in the random fluctuation walk model at finite temperature. The phase transitions are considered in systems where the Critical Point (CP) is a distinct singular one existence of which is dictated by the dynamics of conformal symmetry breaking.
The physical approach to the effective CP is predicted through the influence...
We study the phase diagram and the thermodynamic properties of QCD at nonzero isospin asymmetry at physical quark masses with staggered quarks. In particular, continuum results for the phase boundary between the normal and the pion condensation phases and the chiral/deconfinement transition are presented. Our findings indicate that no pion condensation takes place above T≈160 MeV and also...
We present results for our measurements of the chromoelectric and chromomagnetic fields produced by a static quark-antiquark pair in $SU(3)$ Yang-Mills theory at zero temperature. We propose a method for the extraction of the nonperturbative confining part of the longitudinal chromoelectric field and discuss properties of its spatial structure.
We compute temporal correlators and spectral functions for light, open
charm and charmonium mesons in the pseudoscalar and vector channel for
a range of temperatures below and above the deconfinement transition.
The study is carried out using anisotropic lattice QCD with 2+1
dynamical flavours, a_s=0.123fm and a_s/a_t=3.5. The high-temperature
results are benchmarked by comparing them to...
In this work we investigate the response of the QGP with the constant electrical conductivity to the electromagnetic
fields in asymmetry collisions such as Cu- Au collisions . We study the response of resistive fluid
with finite electrical conductivity σ to the presence of coupled transverse electric and magnetic fields analytically.
Here, we consider the combination of relativistic...
In ultrarelativistic heavy ion collisions enormous magnetic fields are generated because of fast moving charged particles. In the presence of this magnetic field, the spin of particles are aligned either in the parallel or in the antiparallel direction with respect to the direction of the magnetic field. This alignment produces a finite magnetization.
It is kown that finite magnetic...
We analyze the $f_0(500)$ state generated as a pole of $\pi\pi$ scattering within unitarized low-energy effective theories at finite temperature. The relation of that thermal pole with the scalar susceptibility is studied within a scalar saturation approach, which yields results complying with lattice data. The robustness and predictability of this method are studied in terms of the...
In this talk I review some applications of the functional renormalisation group to infrared QCD and asymptotically safe quantum gravity (QG). It is shown that the universal nature of the FRG allows for a surprisingly similar formulation of these two physically very different theories. This allows us to discuss their physics in a rather similar fashion.
In QCD current applications concern the...
We perform various lattice simulations with the energy-momentum tensor in SU(3) Yang-Mills theory. The energy-momentum tensor defined on the basis of the Yang-Mills gradient flow is used in these analyses. We explore the spatial distribution of the stress tensor in quark-anti-quark system and thermodynamic quantities at nonzero temperature, as well as the correlation functions. Extensions of...
I will review anomalous properties of chiral forms of relativistic matter, which attracted a lot of attention recently in the context of heavy-ion physics and in studies of the Early Universe. In part, the recent interest to chiral matter is driven by the intriguing possibility of observing unusual chiral properties that stem directly from quantum anomalies. In addition, the same fundamental...
The Casimir effect is a quantum phenomenon rooted in the fact that vacuum fluctuations of quantum fields are affected by the presence of physical objects and boundaries. As the energy spectrum of vacuum fluctuations depends on distances between (and geometries of) physical bodies, the quantum vacuum exerts a small but experimentally detectable force on neutral objects. Usually, the associated...
Quantum information theoretic concepts such as entanglement entropy provide interesting information on QCD dynamics. I will discuss in particular the role of entanglement in the context of particle production from the Schwinger mechanism for an expanding QCD string. In the bosonized Schwinger model of QED confined to 1+1 dimensions, entanglement between rapidity regions leads actually to a...
Recent measurements from the ATLAS, CMS and LHCb collaborations are testing QCD
with unprecedented precision and in a new energy regime.
This talk covers recent measurements by the LHC experiments on the production of jets, isolated photons, electroweak bosons and top quarks.
High-precision measurements of flavor-transitions are sensitive to the virtual effects of particles at energies beyond the reach of current colliders. In fact, there are measurements of semileptonic B-meson decays which are in tension with the SM predictions and suggest the existence of new lepton non-universal interactions. I will discuss the phenomenological and theoretical implications of...
Production cross sections of heavy quarkonia are considered as useful tools to study various aspects of QCD. Unfortunately, the mechanism of quarkonium production itself remains elusive to this day. Even analyses based on the same formalism can lead to different descriptions of the production process and give contradicting predictions of processes involving heavy quarkonia. In this talk, we...
Ensembles of magnetic defects successfully explain many properties of confinement and are strongly believed to capture the (infrared) YM path-integral measure. In this work, we motivate and propose a measure to compute center element averages where vortices and chains (with non-Abelian d.o.f. and monopole fusion) are differentiated. When center vortices percolate and monopoles condense, using...
Lattice calculations are in progress to study SU(2) gauge theory with one Dirac fermion in the fundamental representation. This model bears some resemblance to QCD but there are also essential differences, such as an enlarged global symmetry and an absence of Goldstone bosons. The model contains a dark matter candidate that remains naturally stable over cosmological timescales.
The ground state of QCD in sufficiently strong magnetic fields and at nonzero baryon chemical potential is a topological crystal made of neutral pions: the Chiral Soliton Lattice (CSL). Due to its topological nature, it carries nonzero baryon number density that can reach values relevant for the cores of neutron stars. The spectrum of excitations above the CSL ground state contains a soft,...
We present the final results from a multi-year [1,2] study of the in-medium spectral properties of heavy quarkonium bound states on the lattice. In this work we combine high statistics N_f=2+1 ensembles from the HotQCD collaboration with the effective theory NRQCD and improved Bayesian spectral reconstruction methods. We corroborate earlier findings on the sequential suppression of quarkonium...
Significant progress has been achieved recently in the determination
of properties of nucleons by lattice methods. This includes studies of
the response of the nucleon to electromagnetic, weak or beyond the
Standard Model probes and the internal dynamics in terms of the
contributions from quarks and gluons. In particular, the systematics
due to simulating in a finite box with a finite lattice...
Studies of the production of heavy quarkonium states are very important to improve our understanding of QCD and hadron formation, given that the heavy quark masses allow the application of theoretical tools less sensitive to nonperturbative effects. Thanks to a dedicated dimuon trigger strategy, combined with the record-level energy and luminosity provided by the LHC, the CMS experiment has...
Recent lattice QCD studies at vanishing density exhibit the parity-doubling structure for the low-lying baryons around the chiral crossover temperature. This finding is likely an imprint of the chiral symmetry restoration in the baryonic sector of QCD, and is expected to occur also in cold dense matter, which makes it of major relevance for compact stars. By contrast, typical effective models...
It has been conjectured that glueballs can be described by knot solitons in a low energy effective model of the Yang-Mills theory. In this talk, we consider knot solitons in the $F_2$ Skyrme-Faddeev-Niemi model, which can be interpreted as a low energy effective model of the $SU(3)$ Yang-Mills theory. It will be shown that the Euler-Lagrange equation reduces to that of the well-known $CP^1$...
In this talk I shall reexamine the possibility of extracting parton distribution functions from lattice simulations. I discuss the case of quasi-parton distribution functions, the more recent proposal of directly trying to compute the current-current $T$-product on the lattice and the possibility of making reference to the reduced Ioffe-time distribution. I show that the process of...
I will review the recent progress in determining the infrared behavior of SU(2) gauge theory with fermions in fundamental representation of the gauge group.
Especially, we will focus on the six and eight fermion cases.
We present recent computations of loop functions in thermal QCD
like the Polyakov loop, correlators of Polyakov loops and Wilson lines,
and the cyclic Wilson loop.
We discuss divergences and how to renormalize them.
Finally we compare with lattice data.
In color-superconducting quark matter gluons and photons mix, and thus an external ordinary magnetic field may induce color-magnetic flux tubes. I will discuss the structure of these flux tubes, in particular pointing out a novel flux tube configuration in color-flavor locked quark matter that has a 2SC core, rather than a completely unpaired one. This configuration is energetically preferred...
The Abelian dominance of the string tension for the fundamental sources in MA gauge was shown in the lattice simulations. However, it is known that, for higher representations, the naive "Abelian" Wilson loop, which is defined by using the diagonal part of the gauge field, does not reproduce the correct behavior. To solve this problem, for an arbitrary representation of an arbitrary gauge...
A Lindblad equation for the evolution of heavy quarkonia in QGP has recently been derived from potential non-relativistic QCD (pNRQCD) and open quantum system framework. We derive the classical limit of the evolution equations for color-singlet and color-octet quarkonia states. Within the classical approximations, we are able to write the evolution equations respectively as a Langevin equation...
The so-called chiral soliton lattice was recently found to describe the ground state of the dense QCD matter in strong magnetic fields. Such a state consists of a periodic array of topological solitons, spontaneously breaks the parity and the translational symmetry and is known to appear also in condensed-matter systems such as chiral magnets. Motivated by the fact that the QCD-like theories...
Direct lattice computation of the key measures of hadron structure such as the form factors, parton distribution functions, quark distribution amplitudes have always been challenging. With current enormous experimental efforts at JLab (with its 12 GeV upgrade), COMPASS in CERN, RHIC-spin and at a future EIC, it is now crucial to test and exploit the newly proposed lattice QCD ideas in hadron...
Charmonium production is a crucial observable in pp and A-A collisions.
Studies on charmonium production in pp collisions can help to understand both fundamental perturbative QCD processes $i.e.$ the initial charm-quark pair production, as well as hadronization mechanisms $i.e.$ the subsequent binding into a charmonium state. $J/\psi$ measurements as a function of multiplicity can help to...
Logarithms of the hard-scattering scale that appear in light-cone
amplitudes can be resummed by making use of the
Efremov-Radyushkin-Brodsky-Lepage (ERBL) evolution equation for the
light-cone distribution amplitude (LCDA). The standard method for
carrying out the evolution is to decompose the LCDA in a series of
eigenfunctions of the lowest-order evolution kernel (Gegenbauer
polynomials)....
We consider a class of gauge-invariant nonlocal quark bilinear operators, including a finite-length Wilson-line (called Wilson-line operators). The matrix elements of these operators are involved in the recent "quasi-distribution" approach for computing parton distributions nonperturbatively.
In this work, we study the renormalization of two types of classes of Wilson-line operators:...
Measurements on dielectrons (electron-positron pairs) produced in ultra-relativistic heavy-ion collisions (HIC) allow the study of the electromagnetic radiation that is emitted through the whole evolution of the system and that is not affected by final state interactions. Through the study of dielectrons at midrapidity one can investigate different phenomena by taking advantage of the degree...
We consider the mass-deformed Yang-Mills theory in the Landau gauge which is obtained by just adding a gluon mass term to the Yang-Mills theory in the Landau gauge. We show that the decoupling solution is well reproduced by taking into account loop corrections from the mass-deformed Yang-Mills theory. Then we derive gluon confinement/deconfinement from the reflection-positivity...
A number of new states have been observed from the Belle experiment
ever since the discovery of the X(3872) in 2003
and related studies are still ongoing by using full Belle data set.
Here we report some of recent results on the charmonium and
charmoniumlike states, and also open charm production based on a large data sample recorded at the
Belle detector at the KEKB...
I will discuss some recent progress in studying excited and exotic mesons using first-principles lattice QCD calculations. In particular, I will present some new work on meson-meson scattering involving mesons with non-zero spin, an area which is important for understanding many of the various puzzling structures that have been observed in experiment but where so far lattice QCD calculations...
Local formulations of quantum field theory provide a powerful framework in which non-perturbative aspects of QCD can be analysed. In this talk I will outline how this approach can be used to elucidate the general analytic features of QCD propagators.
We have measured several 2S-2P transitions in muonic hydrogen ($\mu$p), muonic deuterium ($\mu$d) and muonic helium ions ($\mu^3$He, $\mu^4$He). From muonic hydrogen we extracted a proton charge radius 20 times more precise than obtained from electron-proton scattering and hydrogen high-precision laser spectroscopy but at a variance of $7\sigma$ from these values. This discrepancy is...
The study of the antikaon nucleon system at very low energies plays a key
role in the study of the strong interaction with strangeness, with important
impact in particle and nuclear physics and astrophysics. Exotic atoms
measurements, in particular kaonic hydrogen and deuterium, allow to
determine the s-wave antikaon-nucleon ispospin dependent scattering lengths.
Taking advantage of the...
We study the nonperturbative structure of the quark-photon vertex in Landau gauge. To this end we utilize Green's functions from two-flavor lattice QCD simulations and extract all longitudinal and transversal form factors. Interestingly, our lattice results fit rather well with solutions of the inhomogenous Bethe-Salpether equation of the vertex in the rainbow-ladder approximation. Though,...
The allowed window on new physics to emerge from low-energy precision measurements of hadronic properties and processes relies on theoretical input as well. I review how recent progress in the analysis and computation of baryon matrix elements impact the interpretation of current, planned, and possible experiments in neutron beta decay and searches for neutron-antineutron conversion.
The goal of calculating the one loop hadronic contribution to the muon
anomalous magnetic moment using lattice QCD, with an error under 1%,
requires the calculation of the disconnected contributions. We discuss
some of the numerical challenges of computing disconnected vector
correlators, in lattice QCD calculations using the highly improved
staggered quark (HISQ) action. We report preliminary...
We present the recent results on the confinement/deconfinement transition in lattice SU(2) QCD with two flavors of quarks at finite quark density and zero temperature. In the region $\mu_q$ ∼ 1000 MeV we observe the confinement/deconfinement transition which manifests itself in rising of the Polyakov loop and vanishing of the string tension $\sigma$. After the deconfinement is achieved at...
This talk will describe new tests of quarkonium production using quarkonia that are produced within jets. We study the distribution in the fraction z of a jet's longitudinal momentum carried by the quarkonium. The z distribution is sensitive to the underlying NRQCD production mechanism. Analytic calculations of the z distributions in SCET that incorporate Next-to-Leading-Log (NLL) resummation...
Dyson--Schwinger equations are an established, powerful non-perturbative tool to investigate QCD. In the Hamiltonian formulation of a quantum field theory they allow variational calculations with non-Gaussian wave functionals: by means of DSEs the various $n$-point functions, needed in expectation values of observables like the Hamilton operator, can be thus expressed in terms of the...
A nonzero electric dipole moment (EDM) of the neutron, proton, deuteron or helion, in fact, of any finite system necessarily involves the breaking of a symmetry, either by the presence of external fields (i.e., electric fields leading to the case of induced EDMs) or explicitly by the breaking of the discrete parity and time-reflection symmetries in the case of permanent EDMs. Recent results...
Potential detection of non-conserving lepton number processes, such as the neutrinoless double beta decay, constitutes one of the most promising signals of new physics beyond the Standard Model, apart from experiments using high energy collisions. In the neutrinoless double beta decay (0νββ) two neutrons are transformed into two protons and only two electrons are emitted in the final state....
The PANDA experiment represents the central part of the hadron physics programme
at the new Facility for Antiproton and Ion Research (FAIR) under construction at
GSI/Darmstadt (Germany). The multi-purpose PANDA detector in combination with an
intense and high-quality antiproton beam allows for coverage of a broad range of
different aspects of QCD, and it is best suited for charmonium...
The JIMWLK equation, which describes the evolution of color fields, together with a choice of the initial conditions, for instance according to the Venugopalan-McLerran model, provide a framework in which correlation functions of Wilson lines and their derivatives can be estimated, hence providing necessary information to describe hadron Transverse Momentum Dependent structure functions. After...
The covariant variational approach to Yang-Mills theory is further
developed. After reviewing the extension to finite temperature, we briefly
recall the effective action for the Polyakov loop and the critical
properties of the deconfinement phase transition within this approach.
The thermodynamics of pure Yang-Mills theory are studied in detail and
the resulting equation of state is compared...
We study the Landau gauge quark propagator, at finite temperature, using quenched lattice simulations. Special focus is given to the behaviour of the momentum space form factors across the confinement-deconfinement phase transition.
In the Wilson's lattice formulation of QCD, a fermionic Fock space can be explicitly constructed at each time slice using canonical creation and annihilation operators. The partition function $\mathcal{Z}$ is then represented as the trace of the transfer matrix, which maps the Fock space at time $t$ in the one at time $t+1$. The usual functional representation of $\mathcal{Z}$ as a path...
Charmed mesons and baryons provide an ideal laboratory to probe non-perturbative strong interaction dynamics. The LHCb experiment, with its excellent vertexing, tracking and particle identification capabilities, is very suitable for the study of charmed mesons and baryons, and interesting results in this area have been obtained from several recent analyses of LHCb data. Following the discovery...
One of the main physics goals of the NA61/SHINE programme on strong interactions is the study of the properties of the onset of deconfinement. This goal is pursued by performing an energy (beam momentum 13A - 158A GeV/c) and system size (p+p, p+Pb, Be+Be, Ar+Sc, Xe+La) scan. This talk will review results and plans of NA61/SHINE. In particular, recently obtained inclusive spectra in inelastic...
The search of neutrinoless double-beta decay plays a fundamental role in the understanding of neutrino physics. Its observation would prove that neutrinos are Majorana particles and that lepton number is not conserved, with a profound impact on elementary particle physics, nuclear physics, astrophysics, and cosmology. Experiments presently running will cover the quasi-degeneracy region of the...
Thermodynamics of the quark-gluon plasma at finite density is studied in the framework of the Field Correlator Method, where thermodynamical effects of Polyakov loops and the colormagnetic confinement force (CMC) is defined by the spatial Wilson loop projection are taken into account. It was shown that the CMC potential plays an important role in QGP thermodynamics providing the magnetic Debye...
We compute the effective potential for the Polyakov loop in a pure SU(N) gauge theory beyond two-loop order. We introduce a new approach using the Poisson resummation formula, which is well suited to compute thermal sums/integrals with non-trivial holonomy. We discuss the implications for phenomenology with three colors, and theoretical questions at large N.
After recalling the basis of the Dual QCD (DQCD) and its past successes in Kaon flavour physics within the Standard Model, I will present 2018 results that include the calculation of hadronic matrix elements of four-quark operators for $K^0-\bar K^0$ mixing and $K\to\pi\pi$ decays in arbitrary extension of the Standard Model.
The results for $K^0-\bar K^0$ mixing allow an insight into those...
Lattice QCD is currently our only reliable tool for calculating low-energy nuclear physics observables directly from the Standard Model. It is thus a crucial bridge between high-energy beyond the Standard Model (BSM) matrix elements and precision nuclear experiments looking for these rare BSM signals. In this talk, I will discuss recent lattice QCD results relevant for nuclear BSM searches,...
The extraction of the order of the thermal transition of QCD at zero chemical potential, with two dynamical flavours of massless quarks, has proven to be a formidably difficult task. A first order region is found in the chiral limit only on coarse lattices and employing unimproved fermion discretisations, but whether it survives in the continuum limit is yet far from being known.
This...
We propose a model-independent method to ascertain the leading valence composition of a hadron: to measure the energy dependence of its production cross section at a fixed angle interval. This E-dependence, by the QCD Brodsky-Farrar counting rules, falls at high energy with a steepness that depends on the leading quark and gluon composition.
We exemplify with a reaction that could help...
Complex machine learning tools, such as deep neural networks and gradient boosting algorithms, are increasingly being used to construct powerful discriminative features for High Energy Physics analyses. These methods are typically trained with simulated or auxiliary data samples by optimising some classification or regression surrogate objective. The learned feature representations are then...
I recall the basic properties and history of CLs, a method or procedure to derive robust upper limits in searches for new phenomena that was developed in preparation for Higgs boson searches at LEP200 in the 1990’s.
Taking into account the negative results of searches for new fields, the existence of a gap between SM and New Physics states justifies the use of electroweak effective theories. We consider a non-linear realization of the electroweak symmetry breaking and a set of new heavy states, incorporating colored bosonic and fermionic resonances. By integrating out these heavy resonances, we analyze...
Starting from 2020, future development projects for the Large Hadron Collider will constantly bring nominal luminosity increase, with the ultimate goal of reaching a peak luminosity of $5 · 10^{34} cm^{−2} s^{−1}$ for ATLAS and CMS experiments planned for the High Luminosity LHC (HL-LHC) upgrade. This rise in luminosity will directly result in an increased number of simultaneous proton...
We consider $SU(N)$ QCD in a new quadratic gauge which highlights certain characteristic of the theory in the non-perturbative sector. By considering natural hermiticity property of the ghost fields we cast this model as non-Hermtian but symmetric under combined Parity (P) and Time reversal (T) transformations. We explicitly study the PT phase transition in this model. This is very first...
