We review the determination of the low-energy pion-nucleon scattering amplitude using Roy-Steiner equations. In particular, we focus on the phenomenological determination of the pion-nucleon $\sigma$-term, derived in combination with modern precision data on pionic atoms. We will also discuss recent applications to nucleon form factors and the determination of low-energy constants in chiral...
Most of our present understanding of the nucleon structure derives from inclusive deep inelastic scattering (DIS) experiments performed over the past five decades in different kinematic regimes at fixed-target experiments and collider machines. In the recent years, it has been realized that in DIS reactions, single and dihadron semi-inclusive and hard exclusive production, provide a variety of...
The Argonne-Osaka dynamical coupled-channels (DCC) approach provides a unified description of various electroweak meson productions on single nucleon and nucleus. The model can be used, for example, to extract properties of nucleon resonances through a comprehensive analysis of reaction data, and to evaluate nuclear effects involved in the reactions, thereby enabling us to obtain information...
A comparison between polarization-transfer to a bound proton in quasi-free kinematics by the $A(\vec e,e'\vec p)$ knockout reaction
and that in elastic scattering off a free proton can provide information on the characteristics of the bound proton. In elastic scattering, the ratio of the transverse ($P_x$)
to longitudinal ($P_z$) polarization-transfer components is proportional to the...
Nucleon state in one unitary octet with Lambda(1330), Sigma(1475),and Xi(1620) is discussed. It seems to be possible that its mass is below the Delta. We derive bounds for the properties of such states. Some of these are new [recent evidences came from COSY for Sigma(1475) and Belle for Xi(1620)], while others improve upon
existing limits. We discuss the nature of N' states, and their unitary...
Neutrons have proved themselves to be a useful system to study topics in nuclear, particle, and astrophysics with high-precision, low-energy experiments. At the Fundamental Neutron Physics Beamline (FNPB) at the Spallation Neutron Source (SNS), the NPDGamma experiment investigated the hadronic weak interaction via the capture of cold neutrons on protons. Observation of the hadronic weak...
The two dimensional quantum chromodynamics (QCD) in the limit of infinite number of colors, known as the 't Hooft model, was originally formulated in the Light Front Dynamics (LFD). The theory is exactly solvable, while still bearing some resemblance to the 4 dimensional real world QCD in aspects such as confinement and mass gap, as well as the spontaneous breaking of chiral symmetry. Similar...
The GlueX experiment at Jefferson Lab aims to study the light meson spectrum with an emphasis on the search for hybrid mesons. To this end, a linearly-polarized $9\,$GeV photon beam impinges on a hydrogen target contained within a hermetic detector with near-complete neutral and charged particle coverage. In 2018, the experiment completed its first phase of data taking in its design...
The study of anisotropic flow provides strong constrains to the evolution of the medium produced in heavy ion collisions and its event-by-event geometry fluctuations. The strength and predominance of these observables have long been related to collective behaviour in the formed medium. Recent results in small systems both at RHIC and LHC provide strong arguments for the formation of such...
Three-body unitarity puts important constraints on the form of the scattering amplitudes required for the clarification of several puzzles in modern meson and baryon spectroscopy - e.g. Roper-puzzle, kinemaitic (triangle-) singularities in excited state of a1(1260), nature of XYZ states.
In my talk, I will demonstrate, how a minimal form of such a relativistic and unitary scattering amplitude...
Recent experimental observations of charged charmonium- and bottomonium-like structures have brought lots of excitements in the field of hadron spectroscopy. If these structures are associated with the existence of the corresponding hadrons, these states includes minimally two quarks and two antiquarks, being objects clearly beyond the conventional quark model picture. Such charged...
Polarizabilities are fundamental properties related to the internal structure and dynamics of the nucleon. They play a crucial role not only in our understanding of the nucleon, but also in other areas such as atomic physics. The A2@MAMI Collaboration has undertaken a comprehensive program of real Compton scattering experiments in order to accurately determine these parameters at the MAinz...
Understanding the nature of dark matter is crucial in modern physics.
Among the diff?erent possibilities, the idea that dark matter could be con-
ned into a `dark sector' is attracting growing interest in recent years.
A combination of diff?erent standard model anomalies can be solved by
introducing a mediator particle with mass lower than the weak scale, connecting the dark sector to the...
Generalized Parton Distributions (GPDs) provide simultaneously spatial and momentum distribution of quarks and gluons inside the nucleons. GPDs can be accessed experimentally through hard exclusive processes like Deeply Virtual Compton Scattering (DVCS) or Deeply Virtual Meson Production (DVMP). Experiment E12-06-114 completed half of its data taking at the end of 2016 in Hall A at JLab. This...
In view of the growing need of theoretical tools that can be used in QCD to understand the dynamics of gluons in hadrons, the renormalization group procedure for effective particles (RGPEP) has been applied to several problems in QCD in order to study its utility. The method, based on the Glazek-Wilson similarity renormalization group for Hamiltonians, uses the concept of effective particles,...
The PRad experiment is aimed to determine proton charge radius from electron-proton elastic scattering. The measurements were performed in the experimental Hall B of Jefferson Lab using a novel non-magnetic spectrometer technique and windowless hydrogen gas flow target. This allowed to measure $ep$ scattering at angles as small as $0.7~^\circ$ to access unprecedentedly low $Q^2$ down to...
The GlueX facility, featuring a linearly polarized 9 GeV real photon beam delivered to a large-acceptance detector system, has recently completed its first phase of running, and analysis efforts of this dataset are well underway. It has been suggested that at GlueX energies, quark systems beyond the three quark and quark-antiquark systems of baryons and mesons, such as hybrid mesons,...
The NA62 experiment at CERN SPS was designed to measure BR(K+ -> pi+ nu nu-bar) with in-flight decays, a novel technique for this channel. NA62 took its first physics data in 2016, reaching the sensitivity to the decay at the Standard Model BR. The experiment collected 10 times more statistics in 2017 and a similar amount of data is expected from the 2018 run.
The result on K+ to pi+ nu...
We present a theoretical analysis of $\gamma\gamma^* \to \pi^0\pi^0, \pi^+\pi^-$ and $\gamma\gamma^*\to\pi^0\eta$ processes within the energy range from threshold to 1.4 GeV and the low spacelike virtualities of photons. The Omn`es representation is adopted in order to account for rescattering effects in both s- and d-partial waves, except for $a_2(1320)$, which is approximated as a...
The asymmetry parameter $\alpha_-$ of the parity-violating weak decay $\Lambda \rightarrow p \pi^-$ is a result of interference between $s$- and $p$-waves. The BESIII collaboration recently reported a value of $\alpha_-$ as 0.750(9)(4) - which is significantly higher than the current PDG value of 0.642(13).
In the same time, most of the polarization observables (from CLAS measurements) also...
The E12-09007 experiment in CLAS12 of Hall B at Jefferson lab proposed to measure multiplicities and longitudinal double spin asymmetries for pions (π+,π−, π0) and kaons (K+, K−, K0s) in Semi-Inclusive Deep Inelastic Scattering (SIDIS) from both hydrogen and deuterium. The data will be used to measure the x-dependence of the strange parton distribution function (PDF) and will help constrain...
One of the most striking phenomenon of QCD is the formation of the nucleon out of massless gluons and almost massless quarks. This system of confined quarks and gluons serves as the basic constituent of ordinary baryonic matter and exhibits the characteristic spectra of excited states, which are sensitive to the details of quark confinement. Complementary to nucleon structure studies, nucleon...
A high-luminosity polarized Electron-Ion Collider (EIC) has been recommended for future construction in the 2015 NSAC Long-Range Plan. This facility will enable a next-generation physics program aimed at exploring the three-dimensional structure of the nucleon in QCD (spin, spatial distributions, orbital motion), the dynamics of quarks and gluons in nuclei (nuclear interactions, quark/gluon...
Experimental programs in the fields of nuclear and particle physics are searching for evidence of physics beyond that explained by current theories. Indirect searches using precise measurements of well predicted Standard Model observables allow highly targeted tests that can reach mass and energy scales beyond those directly accessible by today’s high energy accelerators. From our precise...
The Standard Model (SM) of particle physics so far successfully explains almost all particle phenomena, including the recently discovered Higgs boson. However, there are several reasons by which physicists believe that the SM is not the ultimate theory, and that there must be New Physics. Critical tests of fundamental symmetries play important role in search for physics beyond the SM. The...
The GlueX experiment is located in experimental Hall D at Jefferson Lab (JLab) and provides a unique capability to search for hybrid mesons in high-energy photoproduction, utilizing a 9 GeV linearly polarized photon beam. The initial, low-intensity phase of GlueX was recently completed and a high-intensity phase will begin this year which includes an upgraded kaon identification system known...
We'll review the recent developments in pi, eta and vector meson photoproduction at JLab energies. We'll see the theoretical implications of the factorization between the meson dynamics and the target and compare them to the new data obtained by the GlueX detector.
We'll discuss the photoproduction of eta-pi^0 and the sensibility of the observables to the exotic P-wave. We'll present a new...
We report recent beam commissioning results of the LEPS2 solenoid spectrometer at SPring-8. The LEPS2 spectrometer is primarily designed for high-statistics experimental confirmation or exclusion of the $\Theta^+$ with a large angular acceptance, and also for unveiling the hadronic structures of the $\Lambda(1405)$ and other exotic baryon systems. A large time-projection chamber (TPC) is a...
The attractive nature of $\bar{K}N$ interaction has stimulated theoretical and experimental searches for $K^-$ bound states in different systems. In particular, many theoretical calculations devoted to the lightest possible system $\bar{K}NN$ have been performed using different methods: Faddeev equations with coupled channels, variational methods, and some others. All of them agree that a...
A Pomeron-exchange model of the $\gamma p \to J/\psi p$ reaction has been used to make predictions for the on-going experiments at JLab. The parameters of the Pomeron-exchange amplitudes are determined by fitting the total cross section data of $\gamma p \to J/\psi p$ up to very high energy W = 300 GeV. To provide information for the search of nucleon resonances with hidden charm...
Investigating few-body systems with identical particles in a hyperspherical basis yields the problem of obtaining symmetrized hyperspherical functions from functions with arbitrary quantum numbers. This article solves the problem of hyperspherical basis symmetrization for four-,five- ,and six- body systems using Parentage Scheme of Symmetrization. Parentage coefficients corresponding to the...
Lattice QCD allows us to probe the low-lying hadron spectrum in finite-volume using a basis of single- and multi-hadron interpolating operators. Here we examine the effect of including tetraquark operators on the spectrum in the scalar meson sectors containing the $K_0^*(700)/\kappa$ and the $a_0(980)$. We present preliminary results outlining additional states found using tetraquark...
The Jiangmen Underground Neutrino Observatory (JUNO) is a multipurpose neutrino experiment in China with a 20-thousand-ton liquid scintillator detector of 3% (at 1 MeV) at 700-meter deep underground. The major goal of JUNO is determining neutrino mass hierarchy by precisely measuring the energy spectrum of reactor electron antineutrinos at a distance of ~53 km from the powerful reactors of the...
The capability of accelerating a high-intensity polarized $^{3}$He ion beam would provide an effective polarized neutron beam for the study of new high-energy QCD studies of nucleon structure. This development is essential for the future Electron Ion Collider, which could use a polarized $^{3}$He ion beam to probe the spin structure of the neutron. The proposed polarized $^{3}$He ion source...
The large data sample accumulated by the Belle experiment at KEKB asymmetric energy $e^+ e^-$ collider provides opportunities to study charmonia (bottomonia) and charmonium-like (bottomonium-like) exotic particles. In this presentation, we report recent results on these topics from Belle, including searches for $B \to h_c K$, $B \to Y(4260) K$, $B \to X(3872/3915)(\to \chi_{c1}\pi^0) K$ and a...
The current chirally motivated theoretical approaches to low energy $\bar{K}N$ interactions
were reviewed in [1] with a special attention paid to the origin of resonances generated
dynamically within the coupled channels models derived from an effective SU(3) chiral
Lagrangian. The $\Lambda(1405)$ represents a well known resonance of this kind, interpreted
as a molecular $\bar{K}N$ bound...
I discuss a coupled-channel model for heavy quarkonium spectroscopy, based on the Unquenched Quark Model Formalism (UQM) with some modifications. The previous model is used to calculate the masses of $\chi_c(2P)$ and $\chi_b(3P)$ states with threshold corrections. Other applications of the coupled-channel model are briefly discussed.
Stefano Sconfietti$^{1,2}$, Barbara Pasquini$^{1,2}$, and Paolo Pedroni$^{2}$
1: Dipartimento di Fisica, Università degli Studi di Pavia, 27100 Pavia, Italy,
2: Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, 27100 Pavia, Italy
I will discuss the results of the the extraction of static scalar polarizabilities from real Compton scattering (RCS) data off the...
The Landau Fermi liquid theory is an phenomenological approach to strongly interacting normal Fermi system at small excitation energies. It is a model which suggest a point to point correspondence between low energy excitation of non interacting Fermi gas. The model has been widely used to study the properties of liquid He-3, electron in metal and nuclear matter. It gives an effective...
Recent Lattice QCD predictions for the mass of H-dibaryon pointing to the mass region near ΛΛ and Ξ−p thresholds encourage experimental searches. A dedicated experiment (J-PARC E42) is designed to measure Λpπ−, ΛΛ and Ξ−p decays from the H-dibaryon in the 12C(K-,K+) reaction at the K1.8 beam line of J-PARC. A new superconducting Hyperon Spectrometer is now under commissioning, consisting of a...
We calculated the decay widths of hybrid mesons [1], considered as hadrons that carry both quark-antiquark and gluon degrees of freedom.
In the construction of hybrid wave functions we follow the coupling scheme adopted for gluelump studies [2], in which the energy spectrum of gluelumps, which are the states obtained by considering a gluon field bound a static color octet (given for example...
An important tool to study the Nucleon Structure are the Nucleon/Baryon Timelike Form Factors.
Many unexpected features have recently been found by BESIII and other experiments concerning $e^+e^-\rightarrow N \bar{N}$ as well as $e^+e^-\rightarrow B \bar{B}$, close to their thresholds, like for instance:
- oscillations in the Proton Timelike Effective Form Factor as a
function of the...
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory uses pulsed, 1 GeV protons incident on liquid mercury to produce neutron beams. As a byproduct of its operation, the SNS is a source of $\pi^\pm$ and, ultimately, an intense stopped-pion source of neutrinos. The COHERENT collaboration uses this source to investigate coherent elastic neutrino-nucleus scattering (CEvNS), and...
The experimental technique of parity-violating electron scattering has been used for over four decades as a tool to study a variety of physics topics. They include sensitive tests of the electroweak Standard Model as probes for new physics, determination of the contribution of the strange quark sea to the nucleon's electromagnetic properties, and measurements of the neutron distributions in...
The so-called proton radius puzzle, the roughly 4% difference in the extracted values for the root-mean square charge radius of the proton from electron spectroscopy and scattering on one side, and muon spectroscopy on the other, remains unsolved for nine years now. Recent results from spectroscopy and scattering shed new light on the puzzle, but so far fall short of a satisfactory solution....
Despite the successes of the Standard Model of particle physics, it remains a challenge to understand the dynamics of the strong interaction among the building blocks of hadronic matter. At small distance scales or at high energies, the underlying theory, QCD, is well tested and understood. Our understanding of the strong interaction deteriorates dramatically at larger distances scales such as...
KLOE-2 has recorded 5.5/fb of e+e- data at 1.02 GeV.
A status report of the experiment plans and current analyses is given, including recent results in the K-short sector which at the Phi-factory is uniquely tagged by K-long identification.
Our attempt to exploit the lepton-tagging technique to identify gamma-gamma processes in the high-luminosity environment of the Phi-factory, the progress...
At Mainz/Germany, the new electron accelerator MESA (Mainz Energy-Recovering Superconducting Accelerator) for a new generation of fixed-target experiments, is currently under construction. In this talk we report on the status and the science case of MAGIX, which will be operated as an internal target experiment during the energy-recovery operation mode of MESA. The detector will consist of two...
In this talk, I will review some aspects of the heavy-light meson spectroscopy, making connections between theoretical calculations to the recent lattice and experimental results.
Preliminary results from a Jefferson Lab (JLab) experiment on electron deep inelastic scattering (DIS) off the $^3H$ and $^3He$ mirror nuclei will be presented. The experiment (MARATHON, “MeAsurement of the $F_2^n/F_2^p$, d/u RAtios and A=3 EMC Effect in Deep Inelastic Electron Scattering Off the Tritium and Helium MirrOr Nuclei”) completed data taking in Spring 2018, using the JLab 11 GeV...
The CLAS Collaboration has completed the installation of the new CLAS12 Large Acceptance Detector in Hall-B at the Jefferson Laboratory in USA, in view of the operation with electron energies up to 11 GeV.
The experimental program spans over a broad range of od scientific scopes, designed to address fundamental issues in nuclear physics, such as spectroscopy and structure of the excited baryon...
Lattice QCD calculations of resonant meson-meson scattering amplitudes have improved significantly due to algorithmic and computational advances. However, progress in meson-nucleon scattering has been slower due to difficulties in computing the necessary correlation functions, the exponential signal-to-noise problem, and the finite-volume treatment of scattering with fermions. Nonetheless,...
The Fermilab E906/SeaQuest is an experiment aimed at studying the anti-quark distributions in nucleons and nuclei. The experiment uses a 120 GeV proton beam extracted from the Main Injector at Fermilab to collide with various solid and cryogenic targets to study a variety of physics topics ranging from light quark flavor asymmetry to the EMC effect in the nucleon sea. It takes advantage of the...
Several experiments are planned at Jefferson Lab and other facilities which will utilize a solid polarized target to investigate tensor structure functions. This new program will help clarify how the properties of the nucleus arise from the underlying partons, and provide novel information about gluon contributions, quark angular momentum, and the polarization of the quark sea that is not...
The $\Xi$ excited states are not well understood because of less experimental study. In this presentation, we report on the studies of $\Xi(1620)^0$ and $\Xi(1690)^0$ via the $\Xi_c^+ -> \Xi^- \pi^+ \pi^+$ decays by using a data sample collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We observe the $\Xi(1620)^0$ and measure its mass and width. We find an...
Belle II at the electron-positron collider SuperKEKB is the successor to the Belle experiment. Its design luminosity is 8*10^35/(cm^2 s), 40 times the record achieved at KEKB/Belle, at the same center of mass energy in the bottomonium region. Over the next years it is expected to accumulate an integrated luminosity of 50/ab, collecting by far the largest sample of B mesons at electron-positron...
The pion’s makeup of quarks, antiquarks, and gluons (or partons) can be described in terms of
its parton distribution functions (PDFs). These are functions of the partons’ momentum
fraction, $x$, relative to the pion. Recently, we were able to determine the pion’s PDF at high- and
low-$x$ regions using Drell-Yan (DY) and Leading Neutron (LN) data. In the DY process, two
hadrons collide, one...
The BESIII experiment at the Beijing Electron Positron Collider (BEPCII) has collected the world's largest data sample at the $J/\psi$ resonance including 10 billion events, which offers an unique opportunity to study hadron spectroscopy and search for light exotic states. In 2003, BESII reported the first observation of a $p\bar{p}$ mass threshold enhancement $X(p\bar{p})$ in $J/\psi...
Deeply Virtual Compton Scattering (DVCS) is the simplest exclusive process to access Generalized Parton Distributions (GPDs). GPDs encode the correlation between the spacial distribution of partons inside the nucleon and their momentum. An upcoming DVCS experiment in Hall C at Jefferson Lab (Virginia, U.S.A.) will provide the highest precision data in a vast $Q^2$-$x_B$ region accessible by a...
The discovery of XYZ particles is a big challenge for quark model. The model must be extended. By considering the high Fock components, an unquenched quark model is developed. The improved quark-pair creation operator in 3P0 model is invoked to deal with the mixing between quark-antiquark and meson-meson states. Gaussian expansion method is employed to do a high precision calculation of this...
We find that a parton-level hard cross section also generates a phase at two loops in semi-inclusive deeply inelastic scattering (SIDIS) off a polarized nucleon, which represents a new source of transverse single-spin asymmetry different from those in the Sivers function and the Collins function. As an extension of the above analysis, we complete the sources of transverse single spin asymmetry...
The Karlsruhe Tritium Neutrino (KATRIN) experiment aims to make a precision measurement of the effective neutrino mass by leveraging the kinematics of tritium beta decay, with a sensitivity of 0.2eV (90% C.L.). Recent run campaigns, both in standard mode (using molecular Tritium) and calibration mode (using $^{83m}$Kr) operation, have provided a wealth of data. The models which we use to fit...
The GlueX experiment is a photopoduction experiment located at Thomas Jefferson National Lab in Newport News, Virginia. GlueX is capable of making beam asymmetry ($\Sigma$) measurements using a tagged, linearly-polarized 9 GeV photon beam incident on a hydrogen target. Measurements of the beam asymmetry for the exclusive reactions, $\gamma p \rightarrow \eta p$ and $\gamma p \rightarrow \eta'...
To separate the proton structure functions into calculable processes and parton distribution functions (PDFs), there are various schemes such as the Fixed-Flavor Number (FFN) and the General Mass Variable-Flavor Number (GM-VFN) schemes. In this Next-to-Leading Order (NLO) Quantum Chromo Dynamics (QCD) analysis we determine PDFs based on the four different HERA I and II combined, H1-ZEUS...
The BESIII has collected 1.3 billion $J/\psi$ and 478 million $\psi$ events from 2009 to 2016 (10 billion $J/\psi$ now). The huge sample provides an ideal platform for light hadron spectroscopy research. In this talk, we shall introduce four recent analyses on light hadron spectroscopy at BESIII. They are related to glueball candidates, e.g. $\eta(1405)$, $f_{0}(1710)$ and $X(1835)$.
The Heavy Photon Search (HPS) experiment at Jefferson Lab is searching for a new $U(1)$ vector boson ("heavy photon", "dark photon" or $A'$) in the mass range of 20-500 MeV/c$^2$. An $A'$ in this mass region is natural in hidden sector models of light, thermal dark matter. The $A'$ couples to the ordinary photon through kinetic mixing, which induces its coupling to electric charge. Since heavy...
Antikaon hydrogen atoms offer an ideal framework to study strong-interaction processes, allowing to perform experiments at vanishing relative energies between the antikaon and the nucleon, which will give access to the basic low-energy parameters, like the antikaon-nucleon scattering lengths. The antikaon hydrogen reaction is well understood from the recent results obtained from KpX at KEK,...
In recent years, it is found that many of the newly discovered states cannot easily fit into the naïve quark model. Because some of them are located close to two body thresholds, they have been conjectured as molecular states. We propose that one way to unambitiously test such a picture is going to few body (greater than two) systems while the building blocks are the two body subsystems. The...
In this talk, I will discuss two topics:
-
The Schwinger sum rule as a new data-driven dispersive approach for the evaluation of hadronic corrections to the muon g-2.
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Proton-polarizability effects in muonic hydrogen using baryon chiral perturbation theory.
The $\omega$ meson is one of the important particles to describe the nucleon-nucleon interaction. Nevertheless, scattering between the omega meson and nucleon is not well established. Recently we have performed high precision photoproduction experiment of the $\omega$ meson from the proton near the threshold. The total cross sections are determined at incident energies ranging from 1.08 to...
An unbound neutron decays via the weak interaction into a proton, electron, and antineutrino with a lifetime $\tau_n$ of approximately 15 minutes. Within the Standard Model of particle physics, $\tau_n$ is precisely related to two other parameters, the nucleon axial form factor $g_A$ and the CKM matrix element $V_{ud}$. Thus, measurements of two of these parameters determines the third, or...
Lattice calculations allow us to probe the low-lying, non-perturbative spectrum of QCD
using first principles numerical calculations. Here we present the low-lying spectrum
in the scalar sector with vacuum quantum numbers, including in fully dynamical QCD for
the first time the mixing between glueball, q-qbar, and meson-meson states.
As lattice calculations are necessarily restricted to...
We present measurements of the photon beam asymmetry $\Sigma$ for the reaction $\gamma p\to K^+\Sigma^0$(1193) using the GlueX experiment in Jefferson Lab’s Hall D. Data were collected using a linearly polarized photon beam with energy range 8.2-8.8 GeV incident on a liquid hydrogen target. Asymmetries are measured as functions of Mandelstam variables $t$ and $u$. These are the first exclusive...
Finite volume multiple-particle interaction is studied in a two-dimensional complex $\phi^4$ lattice model. The existence of analytical solutions to the $\phi^4$ model in two-dimensional space and time makes it a perfect model for the numerical study of finite volume effects of multi-particle interaction. The spectra from multiple particles are extracted from the Monte Carlo...
Observed baryon asymmetry of the universe (BAU) cannot be explained by the known sources of charge-parity (CP)-violation in the Standard Model (SM). A non-zero permanent electric-dipole-moment (EDM) of fundamental particles, nuclei or atoms, violates CP. Measuring an EDM definitively allows us to gain a handle on additional sources of CP-violation required to explain the observed BAU. EDM of...
Baryon-anti-baryon photoproduction has not been extensively studied at Jefferson Lab energies. At the GlueX Experiment, we observe $\bar{p}p$ and, for the first time, $\overline{\Lambda}\Lambda$ photoproduction (with $\Lambda \to \pi^- p, \overline{\Lambda} \to \pi^+ \overline{p}$) from threshold up to $E_{\gamma}=$ 11.4 GeV. Preliminary spectra from data accumulated during the GlueX Phase-I...
The large data sample accumulated by the Belle experiment at KEKB asymmetric energy $e^+ e^-$ collider provides opportunities
to study hyperons and charmed baryons.
In this presentation, we report recent measurements on these topics from Belle,
including absolute branching fractions of $\Xi_c$ and an observation of new excited $\Omega^-$.
The nucleon axial charge $g_A$, measures the strength of the coupling of the axial current of the standard model to the nucleon, controlling the rate of beta decay, for example. A determination of $g_A$ directly from QCD is complicated by the non-perturbative nature of QCD, but is important for benchmarking the application of lattice QCD to problems in nuclear physics, and for aiding in...
Understanding the nature of the baryon spectrum will provide useful insight of quantum chromodynamics in the non-perturbative regime. Significant progress has been made in the $N^*$ regime, but little is known about doubly-strange hyperons. Most knowledge of the Cascade baryons stems from Kaon-nucleon experiments from the 1960s and 1970s or the more recent CLAS experiment at Jefferson Lab....
The $K^-pp$ is the most essential system of kaonic nuclei, which are expected to be a doorway to dense matter due to the strong $\bar{K}N$ attraction [1]. To clarify the nature of $K^-pp$, theorists have investigated this three-body system with various approaches for a long time [2]. Those theoretical studies have indicated that the $K^-pp$ should be a resonant state of a meson-baryon-baryon...
New models for photo- and electroproduction of kaons on the proton were constructed [1,2,3] utilizing new experimental data from LEPS, GRAAL, and particularly CLAS collaborations. Higher spin nucleon (spin-3/2 and spin-5/2) and hyperon (spin-3/2) resonances were included using the consistent formalism and were found to play an important role in the description of data. In these analyses, we...
We study the effects of the $\Delta$(1232) resonance as an effective degree of freedom in a global analysis of the pion photo-production off nucleons. Cross sections and polarization observables have been calculated for charged and neutral pion channels in relativistic chiral perturbation theory up to third order in the $\delta$ counting. We compare our model with a large database containing...
Following on our recent per-cent-level determination of $g_A$, I will describe our efforts to reduce the theoretical uncertainty from 1% to 0.2%, a level at which we will have a 4-sigma discriminating prediction of the neutron lifetime, to match the level of precision of the current experimental discrepancy. I will describe the challenges that must be overcome and our progress to doing so...
The newly completed JLab experiment E12-17-003 aimed to search for a possible Λnn resonance using the $^3H(e, e’K^+)$(Λnn) reaction. If such a state does exist, the experiment will measure its binding (or excitation) energy and natural width. These measurements will provide extremely important and experimentally determined information, for the first time, that can be used to investigate the...
A unique feature of QCD is the possibility for gluonic degrees of freedom to participate in the construction of hadrons in an analogous manner to valence quarks. The unambiguous identification of such states has been thus far not possible. Heavy hybrids are particularly promising because in the heavy-quark sector systematic tools can be used that are not available in the light-quark sector. In...
The Electric Dipole Moment (EDM) of elementary particles, including hadrons, is considered as one of the most powerful tools to study CP-violation beyond the Standard Model. Such CP-violating mechanisms are searched for to explain the dominance of matter over anti-matter in our universe.
Up to now EDM experiments concentrated on neutral systems, namely neutron, atoms and molecules. Storage...
Nonperturbative quantum chromodynamics poses significant challenges. Primary amongst them is a need to chart the behaviour of QCD's running coupling and masses into the domain of infrared momenta. Contemporary theory is incapable of solving this problem alone but a collaboration with experiment holds a promise for progress. This effort can benefit substantially by exposing the structure of...
This talk will give an overview of the highlights of the MENU-2019 Conference.
The field of multiquark states has been catalyzed in recent years by new experimental and theoretical advances relating to four, five and six quark systems. Significant recent progress has been made in the 6q sector (referred to as the dibaryons or hexaquarks). The existence of dibaryons based on six non-strange quarks has been postulated from theoretical studies based on SU(6) symmetry, with...
The nonleptonic weak decay of Lambda_c->K0bar eta p is analyzed from the viewpoint of probing the N(1535) resonance, which has a big decay branching ratio to eta N. Up to an arbitrary normalization, the invariant mass distribution of eta p is calculated with both the chiral unitary approach and an effective Lagrangian model. Within the chiral unitary approach, the N(1535) resonance is...
