The Chern-Simons theory in two-space one-time dimensions is quantized on the light-front under appropriate gauge-fixing conditions using the Hamiltonian, path integral and BRST formulations.
In a recent paper we have studied the Hamiltonian and path integral quantizations of the conformally gauge-fixed Polyakov D1 brane action in the instant-form of dynamics using the equal world-sheet time framework on t...In a recent paper we have studied the Hamiltonian and path integral quantizations of the conformally gauge-fixed Polyakov D1 brane action in the instant-form of dynamics using the equal world-sheet time framework on the hyperplanes defined by the world- sheet time . In the present work we quantize the same theory in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time , using the standard constraint quantization techniques in the Hamiltonian and path integral formulations. The light-front theory is seen to be a constrained system in the sense of Dirac, which is in contrast to the corresponding case of the instant-form theory, where the theory remains unconstrained in the sense of Dirac. The light-front theory is seen to possess a set of twenty six primary second-class contraints. In the present work Hamiltonian and path integral quantizations of this theory are studied on the light-front.展开更多
Light-front holography leads to a rigorous connection between hadronic amplitudes in a higher dimensional anti-de Sitter(AdS) space and frame-independent light-front wavefunctions of hadrons in(3 + 1)-dimensional phys...Light-front holography leads to a rigorous connection between hadronic amplitudes in a higher dimensional anti-de Sitter(AdS) space and frame-independent light-front wavefunctions of hadrons in(3 + 1)-dimensional physical space-time,thus providing a compelling physical interpretation of the AdS/CFT correspondence principle and AdS/QCD,a useful framework which describes the correspondence between theories in a modified AdS 5 background and confining field theories in physical space-time.To a first semiclassical approximation,where quantum loops and quark masses are not included,this approach leads to a single-variable light-front Schro¨dinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum.The coordinate z in AdS space is uniquely identified with a Lorentz-invariant coordinate ζ which measures the separation of the constituents within a hadron at equal light-front time.The internal structure of hadrons is explicitly introduced and the angular momentum of the constituents plays a key role.We give an overview of the light-front holographic approach to strongly coupled QCD.In particular,we study the photon-to-meson transition form factors(TFFs) FMγ(Q 2) for γ→ M using light-front holographic methods.The results for the TFFs for the η and η ' mesons are also presented.Some novel features of QCD are discussed,including the consequences of confinement for quark and gluon condensates.A method for computing the hadronization of quark and gluon jets at the amplitude level is outlined.展开更多
In the present work we study the Hamiltonian, path integral and BRST formulations of the Chern-Simons-Higgs theory in two-space one-time dimensions, in the so-called broken symmetry phase of the Higgs potential (where...In the present work we study the Hamiltonian, path integral and BRST formulations of the Chern-Simons-Higgs theory in two-space one-time dimensions, in the so-called broken symmetry phase of the Higgs potential (where the phase φ(xμ) of the complex matter field Φ(xμ) carries the charge degree of freedom of the complex matter field and is akin to the Goldstone boson) on the light-front (i.e., on the hyperplanes defined by the fixed light-cone time). The theory is seen to possess a set of first-class constraints and the local vector gauge symmetry. The theory being gauge-invariant is quantized under appropriate gauge-fixing conditions. The explicit Hamiltonian and path integral quantization is achieved under the above light-cone gauges. The Heisenberg equations of motion of the system are derived for the physical degrees of freedom of the system. Finally the BRST quantization of the system is achieved under appropriate BRST gauge-fixing, where the BRST symmetry is maintained even under the BRST light-cone gauge-fixing.展开更多
Recently we have studied the instant-form quantization (IFQ) and the light-front quantization (LFQ) of the conformally gauge-fixed Polyakov D1 brane action using the Hamiltonian and path integral formulations. The IFQ...Recently we have studied the instant-form quantization (IFQ) and the light-front quantization (LFQ) of the conformally gauge-fixed Polyakov D1 brane action using the Hamiltonian and path integral formulations. The IFQ is studied in the equal world-sheet time framework on the hyperplanes defined by the world-sheet time σ0=τ=constant and the LFQ in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time σ+= (τ+σ) =constant. The light-front theory is seen to be a constrained system in the sense of Dirac in contrast to the instant-form theory. However, owing to the gauge anomalous nature of these theories, both of these theories are seen to lack the usual string gauge symmetries defined by the world-sheet reparametrization invariance (WSRI) and the Weyl invariance (WI). In the present work we show that these theories when considered in the presence of background gauge fields such as the NSNS 2-form gauge field Bαβ(σ,τ) or in the presence of U(1) gauge field Aα(σ,τ) and the constant scalar axion field C(σ,τ), then they are seen to possess the usual string gauge symmetries (WSRI and WI). In fact, these background gauge fields are seen to behave as the Wess-Zumino or Stueckelberg fields and the terms containing these fields are seen to behave as Wess-Zumino or Stueckelberg terms for these theories.展开更多
Recently we have studied the instant-form quantization (IFQ) of the conformally gauge-fixed Polyakov D1 brane action with and without a scalar dilaton field using the Hamiltonian and path integral formulations in the ...Recently we have studied the instant-form quantization (IFQ) of the conformally gauge-fixed Polyakov D1 brane action with and without a scalar dilaton field using the Hamiltonian and path integral formulations in the equal world-sheet time framework on the hyperplanes defined by the world- sheet time σ0=τ=constant . The light-front quantization (LFQ) of this theory without a scalar dilaton field has also been studied by us recently. In the present work we study the LFQ of this theory in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time σ+=τ+σ=constant , using the Hamiltonian and path integral formulations. The light-front theory is seen to be a constrained system in the sense of Dirac. The light-front theory is seen to possess a set of twenty seven primary second-class contraints. In the present work Hamiltonian and path integral quantizations of this theory are studied on the light-front.展开更多
We investigated the ground state(1S),radially excited states(2S)and(3S),and orbitally excited state(1P)for the heavy charmonia(cc)and bottomonia(bb)mesons in the light-front quark model(LFQM).The light-front wave func...We investigated the ground state(1S),radially excited states(2S)and(3S),and orbitally excited state(1P)for the heavy charmonia(cc)and bottomonia(bb)mesons in the light-front quark model(LFQM).The light-front wave functions have been successful in explaining various physical properties of meson states in the past,especially for the 1S and 2S states.However,the radially excited state 3S and orbitally excited state 1P have rarely been investigated.In this study,we considered these two excited states and investigated the electromagnetic form factors(EMFFs),charge radii,decay constants,parton distribution functions(PDFs),and the distribution amplitudes(DAs)for the quarkonia system.For the sake of completeness,we also studied the ground and the first excited states of quarkonia mesons.We also illustrated the 3D wave functions for the radially excited states to study their nodal structures.展开更多
The electromagnetic form factors and low-energy observables of the deuteron are studied with the help of the light-front approach, where the deuteron is regarded as a weakly bound state of a proton and a neutron. Both...The electromagnetic form factors and low-energy observables of the deuteron are studied with the help of the light-front approach, where the deuteron is regarded as a weakly bound state of a proton and a neutron. Both the S and D wave interacting vertexes among the deuteron, proton, and neutron are taken into account. Moreover,the regularization functions are also introduced. In our calculations, the vertex and the regularization functions are employed to simulate the momentum distribution inside the deuteron. Our numerical results show that the lightfront approach can roughly reproduce the deuteron electromagnetic form factors, like charge G0, magnetic G1, and quadrupole G2, in the low Q~2 region. The important effect of the D wave vertex on G2is also addressed.展开更多
In this work, we analyse semi-leptonic and non-leptonic weak decays of the heavy baryons： Λ_b,Ξ_b,Ωb and Λ_c,Ξ_c,Ωc. For non-leptonic decay modes, we study only the factorizable channels induced by the external...In this work, we analyse semi-leptonic and non-leptonic weak decays of the heavy baryons： Λ_b,Ξ_b,Ωb and Λ_c,Ξ_c,Ωc. For non-leptonic decay modes, we study only the factorizable channels induced by the external Wemission. The two spectator quarks in the baryonic transitions are treated as a diquark and form factors are calculated in the light-front approach. Using the results for form factors, we also calculate some corresponding semi-leptonic and non-leptonic decay widths. We find that our results are comparable with the available experimental data and other theoretical predictions. Decay branching fractions for many channels are found to reach the level 10^（-3）~10^（-2）,which is promising for discovery in future measurements at BESIII, LHCb and Belle II. The SU（3） symmetry in semi-leptonic decays is examined and sources of symmetry breaking are discussed.展开更多
We investigate the tensor form factors of,and A transitions within the standard light-front(SLF)and the covariant light-front(CLF)quark models(QMs).The self-consistency and Lorentz covariance of CLF QM are analyzed vi...We investigate the tensor form factors of,and A transitions within the standard light-front(SLF)and the covariant light-front(CLF)quark models(QMs).The self-consistency and Lorentz covariance of CLF QM are analyzed via these quantities,and the effects of zero-mode are discussed.For the and A transitions,besides the inconsistency between the results extracted via longitudinal and transverse polarization states,which is caused by the residual-dependent spurious contributions,we find and analyze a“novel”self-consistence problem of the traditional CLF QM,caused by different strategies for dealing with the trace term in CLF matrix element.A possible solution to the problems of traditional CLF QM is discussed and confirmed numerically.Finally,the theoret-ical predictions for the tensor form factors of some and()induced and A transitions are updated within the CLF QM with a self-consistent scheme.展开更多
The semileptonic and nonleptonic decays of the b-flavor vector mesons B_(u,d,s)^(*) and B_(c)^(*) are investigated within the covariant light-front quark model(CLFQM).By calculating the form factors of the transitions...The semileptonic and nonleptonic decays of the b-flavor vector mesons B_(u,d,s)^(*) and B_(c)^(*) are investigated within the covariant light-front quark model(CLFQM).By calculating the form factors of the transitions B_(u,d,s)^(*)→P under the CLFQM,with P denoting a pseudoscalar meson,i.e.,π,K,η_(c)(1S,2S),D_((s)),B_((s)),we predict and discuss several physical observables,including the branching ratios,polarization fractions f_(L),f_(∥),and forward-backward asymmetries A_(FB).The total widths of the single-photon radiative decay channels for these b-flavor vector mesons are estimated using their partial widths.In these considered decays,one can find that the semileptonic decays B_(s)_(*0)→D_(s)^(-)l′+ν_(l′)and B_(c)^(*+)→B_(s)^(0)l′+ν_(l′),η_(c)l′+ν_(l′),with l′being e orτ,and the nonleptonic channels B*+c→B0sπ+,B0sρ+have the largest branching ratios,which can reach up to the 10^(-7) order,and are most likely to be accessible at the future high-luminosity LHCb and Belle-II experiments.展开更多
文摘The Chern-Simons theory in two-space one-time dimensions is quantized on the light-front under appropriate gauge-fixing conditions using the Hamiltonian, path integral and BRST formulations.
文摘In a recent paper we have studied the Hamiltonian and path integral quantizations of the conformally gauge-fixed Polyakov D1 brane action in the instant-form of dynamics using the equal world-sheet time framework on the hyperplanes defined by the world- sheet time . In the present work we quantize the same theory in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time , using the standard constraint quantization techniques in the Hamiltonian and path integral formulations. The light-front theory is seen to be a constrained system in the sense of Dirac, which is in contrast to the corresponding case of the instant-form theory, where the theory remains unconstrained in the sense of Dirac. The light-front theory is seen to possess a set of twenty six primary second-class contraints. In the present work Hamiltonian and path integral quantizations of this theory are studied on the light-front.
基金Supported by the Department of Energy Contract DE-AC02-76SF00515,SLAC-PUB-14525
文摘Light-front holography leads to a rigorous connection between hadronic amplitudes in a higher dimensional anti-de Sitter(AdS) space and frame-independent light-front wavefunctions of hadrons in(3 + 1)-dimensional physical space-time,thus providing a compelling physical interpretation of the AdS/CFT correspondence principle and AdS/QCD,a useful framework which describes the correspondence between theories in a modified AdS 5 background and confining field theories in physical space-time.To a first semiclassical approximation,where quantum loops and quark masses are not included,this approach leads to a single-variable light-front Schro¨dinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum.The coordinate z in AdS space is uniquely identified with a Lorentz-invariant coordinate ζ which measures the separation of the constituents within a hadron at equal light-front time.The internal structure of hadrons is explicitly introduced and the angular momentum of the constituents plays a key role.We give an overview of the light-front holographic approach to strongly coupled QCD.In particular,we study the photon-to-meson transition form factors(TFFs) FMγ(Q 2) for γ→ M using light-front holographic methods.The results for the TFFs for the η and η ' mesons are also presented.Some novel features of QCD are discussed,including the consequences of confinement for quark and gluon condensates.A method for computing the hadronization of quark and gluon jets at the amplitude level is outlined.
文摘In the present work we study the Hamiltonian, path integral and BRST formulations of the Chern-Simons-Higgs theory in two-space one-time dimensions, in the so-called broken symmetry phase of the Higgs potential (where the phase φ(xμ) of the complex matter field Φ(xμ) carries the charge degree of freedom of the complex matter field and is akin to the Goldstone boson) on the light-front (i.e., on the hyperplanes defined by the fixed light-cone time). The theory is seen to possess a set of first-class constraints and the local vector gauge symmetry. The theory being gauge-invariant is quantized under appropriate gauge-fixing conditions. The explicit Hamiltonian and path integral quantization is achieved under the above light-cone gauges. The Heisenberg equations of motion of the system are derived for the physical degrees of freedom of the system. Finally the BRST quantization of the system is achieved under appropriate BRST gauge-fixing, where the BRST symmetry is maintained even under the BRST light-cone gauge-fixing.
文摘Recently we have studied the instant-form quantization (IFQ) and the light-front quantization (LFQ) of the conformally gauge-fixed Polyakov D1 brane action using the Hamiltonian and path integral formulations. The IFQ is studied in the equal world-sheet time framework on the hyperplanes defined by the world-sheet time σ0=τ=constant and the LFQ in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time σ+= (τ+σ) =constant. The light-front theory is seen to be a constrained system in the sense of Dirac in contrast to the instant-form theory. However, owing to the gauge anomalous nature of these theories, both of these theories are seen to lack the usual string gauge symmetries defined by the world-sheet reparametrization invariance (WSRI) and the Weyl invariance (WI). In the present work we show that these theories when considered in the presence of background gauge fields such as the NSNS 2-form gauge field Bαβ(σ,τ) or in the presence of U(1) gauge field Aα(σ,τ) and the constant scalar axion field C(σ,τ), then they are seen to possess the usual string gauge symmetries (WSRI and WI). In fact, these background gauge fields are seen to behave as the Wess-Zumino or Stueckelberg fields and the terms containing these fields are seen to behave as Wess-Zumino or Stueckelberg terms for these theories.
文摘Recently we have studied the instant-form quantization (IFQ) of the conformally gauge-fixed Polyakov D1 brane action with and without a scalar dilaton field using the Hamiltonian and path integral formulations in the equal world-sheet time framework on the hyperplanes defined by the world- sheet time σ0=τ=constant . The light-front quantization (LFQ) of this theory without a scalar dilaton field has also been studied by us recently. In the present work we study the LFQ of this theory in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time σ+=τ+σ=constant , using the Hamiltonian and path integral formulations. The light-front theory is seen to be a constrained system in the sense of Dirac. The light-front theory is seen to possess a set of twenty seven primary second-class contraints. In the present work Hamiltonian and path integral quantizations of this theory are studied on the light-front.
基金Narinder Kumar and Harleen Dahiya would like to acknowledge the research grant received from the Science and Engineering Research Board,Government of India under Teachers Associateship Research Excellence Award(TAR/2021/000157)。
文摘We investigated the ground state(1S),radially excited states(2S)and(3S),and orbitally excited state(1P)for the heavy charmonia(cc)and bottomonia(bb)mesons in the light-front quark model(LFQM).The light-front wave functions have been successful in explaining various physical properties of meson states in the past,especially for the 1S and 2S states.However,the radially excited state 3S and orbitally excited state 1P have rarely been investigated.In this study,we considered these two excited states and investigated the electromagnetic form factors(EMFFs),charge radii,decay constants,parton distribution functions(PDFs),and the distribution amplitudes(DAs)for the quarkonia system.For the sake of completeness,we also studied the ground and the first excited states of quarkonia mesons.We also illustrated the 3D wave functions for the radially excited states to study their nodal structures.
基金Supported by National Natural Science Foundation of China(10975146,11475192)The fund provided by the Sino-German CRC110 “Symmetries and the Emergence of Structure in QCD”FAPESP grant 2011/11973-4 for funding his visit to ICTP-SAIFR
文摘The electromagnetic form factors and low-energy observables of the deuteron are studied with the help of the light-front approach, where the deuteron is regarded as a weakly bound state of a proton and a neutron. Both the S and D wave interacting vertexes among the deuteron, proton, and neutron are taken into account. Moreover,the regularization functions are also introduced. In our calculations, the vertex and the regularization functions are employed to simulate the momentum distribution inside the deuteron. Our numerical results show that the lightfront approach can roughly reproduce the deuteron electromagnetic form factors, like charge G0, magnetic G1, and quadrupole G2, in the low Q~2 region. The important effect of the D wave vertex on G2is also addressed.
基金Supported by National Natural Science Foundation of China(11575110,11655002,11735010)Natural Science Foundation of Shanghai(15DZ2272100)
文摘In this work, we analyse semi-leptonic and non-leptonic weak decays of the heavy baryons： Λ_b,Ξ_b,Ωb and Λ_c,Ξ_c,Ωc. For non-leptonic decay modes, we study only the factorizable channels induced by the external Wemission. The two spectator quarks in the baryonic transitions are treated as a diquark and form factors are calculated in the light-front approach. Using the results for form factors, we also calculate some corresponding semi-leptonic and non-leptonic decay widths. We find that our results are comparable with the available experimental data and other theoretical predictions. Decay branching fractions for many channels are found to reach the level 10^（-3）~10^（-2）,which is promising for discovery in future measurements at BESIII, LHCb and Belle II. The SU（3） symmetry in semi-leptonic decays is examined and sources of symmetry breaking are discussed.
基金Supported by the National Natural Science Foundation of China(11875122)the Program for Innovative Research Team in University of Henan Province(19IRTSTHN018)。
文摘We investigate the tensor form factors of,and A transitions within the standard light-front(SLF)and the covariant light-front(CLF)quark models(QMs).The self-consistency and Lorentz covariance of CLF QM are analyzed via these quantities,and the effects of zero-mode are discussed.For the and A transitions,besides the inconsistency between the results extracted via longitudinal and transverse polarization states,which is caused by the residual-dependent spurious contributions,we find and analyze a“novel”self-consistence problem of the traditional CLF QM,caused by different strategies for dealing with the trace term in CLF matrix element.A possible solution to the problems of traditional CLF QM is discussed and confirmed numerically.Finally,the theoret-ical predictions for the tensor form factors of some and()induced and A transitions are updated within the CLF QM with a self-consistent scheme.
基金partly supported by the National Natural Science Foundation of China(11347030)the Program for Science and Technology Innovation Talents in Universities of Henan Province(14HASTIT037)the Natural Science Foundation of Henan Province,China(232300420116)。
文摘The semileptonic and nonleptonic decays of the b-flavor vector mesons B_(u,d,s)^(*) and B_(c)^(*) are investigated within the covariant light-front quark model(CLFQM).By calculating the form factors of the transitions B_(u,d,s)^(*)→P under the CLFQM,with P denoting a pseudoscalar meson,i.e.,π,K,η_(c)(1S,2S),D_((s)),B_((s)),we predict and discuss several physical observables,including the branching ratios,polarization fractions f_(L),f_(∥),and forward-backward asymmetries A_(FB).The total widths of the single-photon radiative decay channels for these b-flavor vector mesons are estimated using their partial widths.In these considered decays,one can find that the semileptonic decays B_(s)_(*0)→D_(s)^(-)l′+ν_(l′)and B_(c)^(*+)→B_(s)^(0)l′+ν_(l′),η_(c)l′+ν_(l′),with l′being e orτ,and the nonleptonic channels B*+c→B0sπ+,B0sρ+have the largest branching ratios,which can reach up to the 10^(-7) order,and are most likely to be accessible at the future high-luminosity LHCb and Belle-II experiments.
