The bound state Bethe-Salpeter amplitude was expressed by Nakanishi using a two-dimensional integral representation, in terms of a smooth weight function g, which carries the detailed dynamical information. A similar, but one-dimensional, integral representation can be obtained for the Light-Front wave function in terms of the same weight function g. By using the generalized Stieltjes...
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\Large{\bf Charm production in interactions of antiprotons with proton and nuclei
at ${\bar P}ANDA$ facility
}\
\vskip 0.1in
{\large{\bf R.~Shyam$^1$ and...
We take into account dynamical spin effects in the holographic light-front wavefunction of the pion in order to predict the pion decay constant, radius, EM form factor, Distribution Amplitude and Transition form factor. We report a remarkable improvement in the description of all data.
We study the Wigner distributions for a physical electron, which reveal the multidimensional images of the electron. The physical electron is considered as a composite system of a bare electron and photon. The Wigner distributions for an unpolarized, longitudinally polarized and transversely polarized electron are presented in transverse momentum plane as well as in impact...
We study the Wigner distribution of gluon in light-front dressed quark model using the overlap of light front wave functions (LFWFs). In a dressed quark model, instead of a proton state, we assume the target state as a composite spin 1/2 state of quark dressed with a gluon. This state allows us to calculate the gluon Wigner distribution analytically in term of LFWFs using Hamiltonian...
Latest results from the CMS experiment on studies of Higgs boson production are presented. Searches involving 125 GeV Higgs boson using various Standard Model production and decay modes have been performed using proton proton collisions from data accumulated during the LHC Run II with center of mass energy of 13 TeV. Similar dataset have also been used to place constraints on physics beyond...
During the LHC Run 2, the CMS experiment has so far recorded ~50 /fb of proton-proton collision data at sqrt(s)=13 TeV. With such a large volume of data-set at an unprecedented energy, CMS has updated most of its new physics searches while the precision on various SM measurements has substantially improved. This presentation would feature most recent results on Higgs boson, Top quark, flavor...
In this talk, I will consider the instant-form and light-front quantization
of some field theory models and demonstrate the advantages of the light-front
quantization over the instant-form quantization.
The instant form and the front form of relativistic dynamics proposed by Dirac in 1949 can be linked by introducing an interpolating angle. Entwining the fermion propagator interpolation with our previous works of the interpolating helicity spinors[1] and the electromagnetic gauge field interpolation[2], we now complete the interpolation between these two forms of quantum electrodynamics...
At very low Bjorken x, parton densities in a nucleon/nucleus reach a point where the gluons are expected to transit to a saturation regime. The saturation scale ($Q_s$) is defined as the inverse of typical transverse inter-partonic distance and can be expressed as $Q_s\sim(A/x)^{1/3}$. So far no clear experimental observation of the onset of gluon saturation has been made. Observables at...
Using the light-front kaon wave function based on a Bethe-Salpeter amplitude model for the quark-meson interaction, we study the electromagnetic form factors, decay constants and charge radii of the kaon in nuclear medium within the framework of light-front ?eld theory.
The kaon model we adopt is well constrained by previous studies to explain the kaon properties in vacuum.
The above mentioned...
We evaluate both chirally even and odd generalized parton distributions(GPDs) in the leading twist in a recently proposed quark-diquark model for the proton where the light-front wavefunctions are constructed from the soft-wall AdS/QCD prediction. The GPDs in transverse impact parameter space give the spin densities for different quark and proton polarizations. For longitudinally polarized...
Transverse momentum dependent parton distributions (TMDs) encode three
dimensional structure as well as angular momentum information of a hadron and hence have attracted a lot of attention in recent time. We present all the twist-2 TMDs for proton in a light-front quark-diquark model (LFQDM) where the light front wave functions are modeled from AdS/QCD prediction. The relations among
the TMDs...
In this contribution I will review the recent advances in the description of light mesons, in particular the pion, as solutions of the Bethe-Salpeter equation in Minkowski space. The tool to solve the Bethe-Salpeter equation is the Nakanishi integral representation and light-front projection. Results for a "mock" pion light-front wave function based on a massive vector exchange, mimicking the...
In this talk I will report our recent progress on nonperturbative renormalization scheme in Hamiltonian light-front theory. Our study is based on Basis Light-front Quantization (BLFQ), a nonperturbative method in Hamiltonian formalism and with Fock-sector truncation. So far our study has been focusing on the physical electron system (in |e>+|egamma>) and the positronium system (in...
We predict the rate of diffractive phi meson electro-production using the Impact-parameter dependent Color Glass Condensate dipole model. We use an anti de -Sitter/quantum chromodynamics holographic light front wavefunction. Our predictions are compared to the available HERA data.
We introduce a covariant approach in Minkowski space for the description of quarks and mesons that exhibits both chiral-symmetry breaking and confinement. Our quark-antiquark interaction kernel is the sum of a one-gluon exchange and a covariant generalization of the linear confining interaction. We assume a Lorentz vector structure for the one-gluon-exchange and a mixed equally-weighted...
We study the decay constants of pseudoscalar and vector $B$ meson in the framework of light cone quark model (LCQM). We apply the variational method to the relativistic Hamiltonian with the Gaussian-type trial wave function to obtain the values of $\beta$ (scale parameter). Then with the help of known values of constituent quark masses, we obtain the numerical results for the decay constants...
Understanding the hadronic interactions from basic principles is one of the most important challenges in modern nuclear/particle physics.
This task is very difficult and it is therefore important to perform non-perturbative studies of few-body systems using simple models, in order to understand the response of such systems to different contributions to the interaction.
For example, ladder and...
Many beyond-Standard-Model (BSM) theories predict massive new particles. The detection of such massive particles at the Large Hadron Collider (LHC) is very challenging. Heavy mass of these particles ensures their dominant decay to top quarks. The top quarks coming from such massive particles are heavily boosted. Thus, the search for boosted tops allows the detection for these particles.
We...
I will discuss the results of searches for various new physics phenomena in the pp collisions at 13 TeV delivered by LHC and collected with the CMS detector in last couple of years. These searches cover a broad spectrum of beyond standard model physics models. In many cases, these results are the most stringent limits on these new phenomena.
Properties of nuclear matter at large densities have been investigated by colliding nuclei at progressively increasing energies over the last three decades. The features of strongly interacting matter have been studied systematically in collisions of a wide range of interacting-system sizes. The ALICE experiment at CERN continues to record data in pp collisions and in Pb-Pb collisions at the...
Gluon SIvers function (GSF) and Boer-Mulders function (BMF) have been receiving lot of interest both
theoretically and experimentally, as they provide the information about the spin nature of the hadron.
GSF describes the distribution of unpolarized gluons inside the transversely polarized proton. Gluon version
BMF represents the density of linearly polarized gluons inside an unpolarized...
The annihilation or production process $e^++e^-\rightarrow
\rho^+ + \rho^- $ is studied with respect to the
universal perturbative QCD (pQCD) predictions. Sub-leading contributions
are considered together with the universal leading pQCD amplitudes such that
the matrix elements of the $\rho$-meson electromagnetic current satisfy
the constraint from the light-front angular condition. The ...
In this talk I would present some fascinating new results obtained
in the gravity theory in general relativity.
We investigate the Generalized Transverse-Momentum Dependent Distributions (GTMDs) describing the parton structure of hadrons using the light-front scalar-diquark model. In particular, we study the twist-2 GTMDs for scalar ($\gamma ^+$) diquark and the corresponding Wigner distributions for the unpolarized, longitudinally unpolarized and transversely unpolarized proton. The relation of...
A remarkable feature of QCD is that the mass scale which controls color confinement and hadron mass scales
does not appear explicitly in the QCD Lagrangian. However, de Alfaro, Fubini, and Furlan have shown that a
mass scale $\kappa$ can appear in the equations of motion without affecting the conformal invariance of the action if one
adds a term to the Hamiltonian proportional to the...
The Belle II experiment at the asymmetric e+ e− SuperKEKB collider is a major upgrade of the Belle experiment, which ran at the KEKB collider at the KEK laboratory in Japan. The design luminosity of SuperKEKB is 8 × 10$^{35}$ cm$^{−2}$ s$^{−1}$, 40 times higher than that of KEKB. The expected integrated luminosity of Belle II is 50 ab$^{−1}$, 50 times higher than that of Belle. The experiment...
We present a review of a few operator solutions of the Schwinger model found it the past along with a new solution obtained within the light-front field theory. In the former results, a few subtle points, related to the residual gauge invariance in the covariant gauge and to the choice of field variables, are identified and an improvement is suggested. Then a summary of the previous...
In the present work, we have studied the transverse momentum distributions (TMDs) in spin-one diquark model. We have used the overlap representation of light-front wave functions (LFWFs) where the spin-1/2 relativistic composite system consists of spin-1/2 fermion and spin-1 vector boson. The results have been obtained for T-even TMDs ( h_{1} and h_{1T}^{perp} ) in transverse momentum plane...
Large Transverse Single Spin Asymmetries ($A_N$) for forward rapidity inclusive hadron production have been observed over a wide range of center of mass energies. This large $A_N$ has been described by phenomenological TMD models like Sivers and Collins mechanisms for initial and final state effects respectively, or by higher twist contributions in the initial and final states. It is...
We propose the low-virtuality leptoproduction of open charm, $p^\uparrow l\rightarrow D^0+X$, treated here in a generalized parton model framework, as a probe of the gluon Sivers function
Jet quenching provides tomographic information of the evolution of the QCD matter formed
in the ultra-relativistic heavy ion collisions.
Perturbative QCD calculation for the jet quenching requires the informations of both elastic and
inelastic scatterings. We study the heavy quark radiative
energy loss in a dynamically screened expanding QCD medium by incorporating the
off-equilibrium...
Wilson lines have a number of uses in non-abelian gauge theories. A topical example in QCD is the description of radiation in the soft or collinear limit, which must often be resummed to all orders in perturbation theory. The relevant functions needed to describe this radiation involve Wilson lines, and new methods are needed to extend such calculations beyond the state of the...
We study $Z_N$ symmetry in $SU(N)+$Higgs theories. The $Z_N$ symmetry can act only
on the gauge fields, the action is not invariant. This leads to explicit breaking of $Z_N$ symmetry. However, we find that the strength of the explicit breaking depends on the parameters of the theory, vanishing in parts of the symmetric phase. According to conventional expectations the symmetry is restored only...
