Ivan Schmidt - Academia.edu (original) (raw)
Papers by Ivan Schmidt
arXiv: High Energy Physics - Phenomenology, 2020
We propose a low scale renormalizable trinification theory that successfully explains the flavour... more We propose a low scale renormalizable trinification theory that successfully explains the flavour hierarchies, neutrino puzzle, dark matter and leptogenesis. The proposed theory is based on the SU(3)CtimesSUleft(3right)LtimesSUleft(3right)RSU(3)_{C}\times SU\left(3\right)_{L}\times SU\left( 3\right)_{R}SU(3)CtimesSUleft(3right)LtimesSUleft(3right)R gauge symmetry, which is supplemented with an additional flavor symmetry Uleft(1right)XtimesmathbbZ2left(1right)timesmathbbZ2left(2right)U\left( 1\right)_{X}\times \mathbb{Z}_{2}^{\left(1\right) }\times \mathbb{Z}_{2}^{\left( 2\right) }Uleft(1right)XtimesmathbbZ2left(1right)timesmathbbZ2left(2right). In the proposed model the top quark and the exotic fermions do acquire tree-level masses, whereas the SM charged fermions lighter than the top quark gain one-loop level masses. In addition, the light active neutrino masses arise from a combination of radiative and type I seesaw mechanisms, with the Dirac neutrino mass matrix generated at one loop level.
Journal of High Energy Physics
A correction to this paper has been published: https://doi.org/10.1007/JHEP05(2023)054
Arxiv preprint hep-ph/ …, 2000
Abstract: We discuss some generic properties of lepton number violating (\ Lv) processes and thei... more Abstract: We discuss some generic properties of lepton number violating (\ Lv) processes and their relation to different entries of the Majorana neutrino mass matrix. Present and near future experiments searching for these processes, except the neutrinoless double beta ...
Brazilian Journal of Physics, 2008
The azimuthal asymmetry of direct photons originating from primary hard scatterings between parto... more The azimuthal asymmetry of direct photons originating from primary hard scatterings between partons is calculated. This can be accounted for by the inclusion of the color dipole orientation, which is sensitive to the rapid variation of the nuclear profile. To this end we introduce the dipole orientation within the saturation model of Golec-Biernat and Wüsthoff, while preserving all its features at the cross-section level. We show that the direct photon elliptic anisotropy v2 coming from this mechanism changes sign and becomes negative for peripheral collisions, albeit it is quite small for nuclear collisions at the RHIC energy.
Astronomy and Astrophysics, 2002
We employ an effective gravitational stellar final collapse model which contains the relevant phy... more We employ an effective gravitational stellar final collapse model which contains the relevant physics involved in this complex phenomena: spherical radical infall in the Schwarzschild metric of the homogeneous core of an advanced star, giant magnetic dipole moment, magnetohydrodynamic material response and realistic equations of state (EOS). The electromagnetic pulse is computed both for medium size cores undergoing hydrodynamic bounce and large size cores undergoing black hole formation. We clearly show that there must exist two classes of neutron stars, separated by maximum allowable masses: those that collapsed as solitary stars (dynamical mass limit) and those that collapsed in binary systems allowing mass accretion (static neutron star mass). Our results show that the electromagnetic pulse spectrum associated with black hole formation is a universal signature, independent of the nuclear EOS. Our results also predict that there must exist black holes whose masses are less than the static neutron star stability limit.
![Research paper thumbnail of The Quark-Antiquark Asymmetry of the Nucleon Sea From [Lambda] and Fragmentation](https://attachments.academia-assets.com/69169457/thumbnails/1.jpg)
](Physics Letters B, 2000
We present a general analysis of the spin transfer for Λ and production in deep-inelastic scatter... more We present a general analysis of the spin transfer for Λ and production in deep-inelastic scattering of polarized charged leptons on the nucleon, and find that the pattern of different behaviors of Λ and production observed by the E665 Collaboration suggests the possibility of quark ...
We study the transverse momentum dependent quark-gluon-quark correlation function. Using a specta... more We study the transverse momentum dependent quark-gluon-quark correlation function. Using a spectator diquark model, we calculate the eight time-reversal-odd interaction-dependent twist-3 quark distributions appearing in the decomposition of the transverse momentum dependent quark-gluon-quark correlator. In order to obtain finite results, we assume a dipole form factor for the nucleon-quark-diquark coupling, instead of a point-like coupling. The results are compared with the timereversal-odd interaction-independent twist-3 TMDs calculated in the same model.
We study the orbital angular momentum structure of the quarks inside the proton. By employing the... more We study the orbital angular momentum structure of the quarks inside the proton. By employing the light-cone diquark model and the overlap representation formalism, we calculate the chiral-even generalized parton distribution functions (GPDs) H q (x, ξ, ∆ 2), H q (x, ξ, ∆ 2) and E q (x, ξ, ∆ 2) at zero skewedness for q = u and d quarks. In our model E u and E d have opposite sign with similar size. Those GPDs are applied to calculate the orbital angular momentum (OAM) distributions, showing that L u (x) is positive, while L d (x) is consistent with zero compared with L u (x). We introduce the impact parameter dependence of the quark OAM distribution. It describes the position space distribution of the quark orbital angular momentum at given x. We found that the impact parameter dependence of the quark OAM distribution is axially symmetric in the light-cone diquark model.
Physical Review D - PHYS REV D, 2007
Diffractive production of heavy flavors is calculated within the light-cone dipole approach. Nove... more Diffractive production of heavy flavors is calculated within the light-cone dipole approach. Novel leading twist mechanisms are proposed, which involve both short and long transverse distances inside the incoming hadron. Nevertheless, the diffractive cross section turns out to be sensitive to the primordial transverse momenta of projectile gluons, rather than to the hadronic size. Our calculations agree with the available data for diffractive production of charm and beauty, and with the observed weak variation of the diffraction-to-inclusive cross section ratios as function of the hard scale.
Brazilian Journal of Physics, 2007
This lecture presents a short review of the main features of diffractive processes and QCD inspir... more This lecture presents a short review of the main features of diffractive processes and QCD inspired models. It includes the following topics: (1) Quantum mechanics of diffraction: general properties; (2) Color dipole description of diffraction; (3) Color transparency; (4) Soft diffraction in hard reactions: DIS, Drell-Yan, Higgs production; (5) Why Pomerons interact weakly; (6) Small gluonic spots in the proton; (7) Diffraction near the unitarity bound: the Goulianos-Schlein "puzzle"; (8) Diffraction on nuclei: diffractive Color Glass; (9) CGC and gluon shadowing.
Physics Letters B, 2002
Recent measurements from the HERMES and SMC collaborations show a remarkably large azimuthal sing... more Recent measurements from the HERMES and SMC collaborations show a remarkably large azimuthal single-spin asymmetries A UL and A U T of the proton in semi-inclusive pion leptoproduction γ * (q)p → πX. We show that final-state interactions from gluon exchange between the outgoing quark and the target spectator system leads to single-spin asymmetries in deep inelastic lepton-proton scattering at leading twist in perturbative QCD; i.e., the rescattering corrections are not power-law suppressed at large photon virtuality q 2 at fixed x bj . The existence of such single-spin asymmetries requires a phase difference between two amplitudes coupling the proton target with J z p = ± 1 2 to the same final-state, the same amplitudes which are necessary to produce a nonzero proton anomalous magnetic moment. We show that the exchange of gauge particles between the outgoing quark and the proton spectators produces a Coulomb-like complex phase which depends on the angular momentum L z of the proton's constituents and thus is distinct for different proton spin amplitudes. The single-spin asymmetry which arises from such final-state interactions does not factorize into a product of structure function and fragmentation function, and it is not related to the transversity distribution δq(x, Q) which correlates transversely polarized quarks with the spin of the transversely polarized target nucleon.
Physical Review C, 2006
The cross sections for a variety of channels of proton-nucleus interaction associated with large ... more The cross sections for a variety of channels of proton-nucleus interaction associated with large gaps in rapidity are calculated within the Glauber-Gribov theory. We found inelastic shadowing corrections to be dramatically enhanced for such events. We employ the light-cone dipole formalism which allows to calculate the inelastic corrections to all orders of the multiple interaction. Although Gribov corrections are known to make nuclear matter more transparent, we demonstrate that in some instances they lead to an opaqueness. Numerical calculations are performed for the energies of the HERA-B experiment, and the RHIC-LHC colliders.
Physical Review D, 2010
The nucleon helicity-independent generalized parton distributions (GPDs) of quarks are calculated... more The nucleon helicity-independent generalized parton distributions (GPDs) of quarks are calculated in the zero skewness case, in the framework of the AdS/QCD model. The present approach is based on a matching procedure of sum rules relating the electromagnetic form factors to GPDs and AdS modes.
Journal of Physics G: Nuclear and Particle Physics, 1998
Two new sum rules for the quark tensor charges of the nucleon are proposed, based on a relation c... more Two new sum rules for the quark tensor charges of the nucleon are proposed, based on a relation connecting the quark transversity distributions to the quark helicity distributions and the quark model spin distributions, and on the sum rules for the quark helicity distributions. ...
Physical Review D, 1994
A beam of relativistic antihydrogen atoms-the bound state (Fe+)-can be created by circulating the... more A beam of relativistic antihydrogen atoms-the bound state (Fe+)-can be created by circulating the beam of an antiproton storage ring through an internal gas target . An antiproton that passes through the Coulomb field of a nucleus of charge 2 will create e+e-pairs, and antihydrogen will form when a positron is created in a bound rather than a continuum state about the antiproton. The -cross section for this process is calculated to be N 4Z2 pb for antiproton momenta above 6 GeV/c. The gas target of Fermilab Accumulator experiment E760 has already produced an unobserved N 34 antihydrogen atoms, and a sample of _ N 760 is expected in 1995 from the successor experiment E835. No other source of antihydrogen exists. A simple method for detecting relativistic antihydrogen ,is -proposed and a method outlined of measuring the antihydrogen Lamb shift .g-',. to N 1%.
We propose a novel mechanism for exclusive diffractive Higgs production pp → pHp in which the Hig... more We propose a novel mechanism for exclusive diffractive Higgs production pp → pHp in which the Higgs boson carries a significant fraction of the projectile proton momentum. This mechanism will provide a clear experimental signal for Higgs production due to the small background in this kinematic region. The key assumption underlying our analysis is the presence of intrinsic heavy flavor components of the proton bound state, whose existence at high light-cone momentum fraction x has growing experimental and theoretical support. We also discuss the implications of this picture for exclusive diffractive quarkonium and other channels.
A new scenario, alternative to energy loss, for the observed suppression of high-p T hadrons obse... more A new scenario, alternative to energy loss, for the observed suppression of high-p T hadrons observed at RHIC is proposed. In the limit of a very dense medium crated in nuclear collisions the mean free-path of the produced (pre)hadron vanishes, and and the nuclear suppression, R AA is completely controlled by the production length. The RHIC data are well explained in a parameter free way, and predictions for LHC are provided.
Arxiv preprint arXiv:1003.4188, 2010
We evaluate the shadowing effect in deeply virtual and real Compton scattering on nuclei in the f... more We evaluate the shadowing effect in deeply virtual and real Compton scattering on nuclei in the framework of the color dipole model. We rely on the soft photon wave function derived in the instanton vacuum model, and employ the impact parameter dependent phenomenological elastic dipole amplitude. Both the effects of quark and the gluon shadowing are taken into account.
arXiv: High Energy Physics - Phenomenology, 2020
We propose a low scale renormalizable trinification theory that successfully explains the flavour... more We propose a low scale renormalizable trinification theory that successfully explains the flavour hierarchies, neutrino puzzle, dark matter and leptogenesis. The proposed theory is based on the SU(3)CtimesSUleft(3right)LtimesSUleft(3right)RSU(3)_{C}\times SU\left(3\right)_{L}\times SU\left( 3\right)_{R}SU(3)CtimesSUleft(3right)LtimesSUleft(3right)R gauge symmetry, which is supplemented with an additional flavor symmetry Uleft(1right)XtimesmathbbZ2left(1right)timesmathbbZ2left(2right)U\left( 1\right)_{X}\times \mathbb{Z}_{2}^{\left(1\right) }\times \mathbb{Z}_{2}^{\left( 2\right) }Uleft(1right)XtimesmathbbZ2left(1right)timesmathbbZ2left(2right). In the proposed model the top quark and the exotic fermions do acquire tree-level masses, whereas the SM charged fermions lighter than the top quark gain one-loop level masses. In addition, the light active neutrino masses arise from a combination of radiative and type I seesaw mechanisms, with the Dirac neutrino mass matrix generated at one loop level.
Journal of High Energy Physics
A correction to this paper has been published: https://doi.org/10.1007/JHEP05(2023)054
Arxiv preprint hep-ph/ …, 2000
Abstract: We discuss some generic properties of lepton number violating (\ Lv) processes and thei... more Abstract: We discuss some generic properties of lepton number violating (\ Lv) processes and their relation to different entries of the Majorana neutrino mass matrix. Present and near future experiments searching for these processes, except the neutrinoless double beta ...
Brazilian Journal of Physics, 2008
The azimuthal asymmetry of direct photons originating from primary hard scatterings between parto... more The azimuthal asymmetry of direct photons originating from primary hard scatterings between partons is calculated. This can be accounted for by the inclusion of the color dipole orientation, which is sensitive to the rapid variation of the nuclear profile. To this end we introduce the dipole orientation within the saturation model of Golec-Biernat and Wüsthoff, while preserving all its features at the cross-section level. We show that the direct photon elliptic anisotropy v2 coming from this mechanism changes sign and becomes negative for peripheral collisions, albeit it is quite small for nuclear collisions at the RHIC energy.
Astronomy and Astrophysics, 2002
We employ an effective gravitational stellar final collapse model which contains the relevant phy... more We employ an effective gravitational stellar final collapse model which contains the relevant physics involved in this complex phenomena: spherical radical infall in the Schwarzschild metric of the homogeneous core of an advanced star, giant magnetic dipole moment, magnetohydrodynamic material response and realistic equations of state (EOS). The electromagnetic pulse is computed both for medium size cores undergoing hydrodynamic bounce and large size cores undergoing black hole formation. We clearly show that there must exist two classes of neutron stars, separated by maximum allowable masses: those that collapsed as solitary stars (dynamical mass limit) and those that collapsed in binary systems allowing mass accretion (static neutron star mass). Our results show that the electromagnetic pulse spectrum associated with black hole formation is a universal signature, independent of the nuclear EOS. Our results also predict that there must exist black holes whose masses are less than the static neutron star stability limit.
Physics Letters B, 2000
We present a general analysis of the spin transfer for Λ and production in deep-inelastic scatter... more We present a general analysis of the spin transfer for Λ and production in deep-inelastic scattering of polarized charged leptons on the nucleon, and find that the pattern of different behaviors of Λ and production observed by the E665 Collaboration suggests the possibility of quark ...
We study the transverse momentum dependent quark-gluon-quark correlation function. Using a specta... more We study the transverse momentum dependent quark-gluon-quark correlation function. Using a spectator diquark model, we calculate the eight time-reversal-odd interaction-dependent twist-3 quark distributions appearing in the decomposition of the transverse momentum dependent quark-gluon-quark correlator. In order to obtain finite results, we assume a dipole form factor for the nucleon-quark-diquark coupling, instead of a point-like coupling. The results are compared with the timereversal-odd interaction-independent twist-3 TMDs calculated in the same model.
We study the orbital angular momentum structure of the quarks inside the proton. By employing the... more We study the orbital angular momentum structure of the quarks inside the proton. By employing the light-cone diquark model and the overlap representation formalism, we calculate the chiral-even generalized parton distribution functions (GPDs) H q (x, ξ, ∆ 2), H q (x, ξ, ∆ 2) and E q (x, ξ, ∆ 2) at zero skewedness for q = u and d quarks. In our model E u and E d have opposite sign with similar size. Those GPDs are applied to calculate the orbital angular momentum (OAM) distributions, showing that L u (x) is positive, while L d (x) is consistent with zero compared with L u (x). We introduce the impact parameter dependence of the quark OAM distribution. It describes the position space distribution of the quark orbital angular momentum at given x. We found that the impact parameter dependence of the quark OAM distribution is axially symmetric in the light-cone diquark model.
Physical Review D - PHYS REV D, 2007
Diffractive production of heavy flavors is calculated within the light-cone dipole approach. Nove... more Diffractive production of heavy flavors is calculated within the light-cone dipole approach. Novel leading twist mechanisms are proposed, which involve both short and long transverse distances inside the incoming hadron. Nevertheless, the diffractive cross section turns out to be sensitive to the primordial transverse momenta of projectile gluons, rather than to the hadronic size. Our calculations agree with the available data for diffractive production of charm and beauty, and with the observed weak variation of the diffraction-to-inclusive cross section ratios as function of the hard scale.
Brazilian Journal of Physics, 2007
This lecture presents a short review of the main features of diffractive processes and QCD inspir... more This lecture presents a short review of the main features of diffractive processes and QCD inspired models. It includes the following topics: (1) Quantum mechanics of diffraction: general properties; (2) Color dipole description of diffraction; (3) Color transparency; (4) Soft diffraction in hard reactions: DIS, Drell-Yan, Higgs production; (5) Why Pomerons interact weakly; (6) Small gluonic spots in the proton; (7) Diffraction near the unitarity bound: the Goulianos-Schlein "puzzle"; (8) Diffraction on nuclei: diffractive Color Glass; (9) CGC and gluon shadowing.
Physics Letters B, 2002
Recent measurements from the HERMES and SMC collaborations show a remarkably large azimuthal sing... more Recent measurements from the HERMES and SMC collaborations show a remarkably large azimuthal single-spin asymmetries A UL and A U T of the proton in semi-inclusive pion leptoproduction γ * (q)p → πX. We show that final-state interactions from gluon exchange between the outgoing quark and the target spectator system leads to single-spin asymmetries in deep inelastic lepton-proton scattering at leading twist in perturbative QCD; i.e., the rescattering corrections are not power-law suppressed at large photon virtuality q 2 at fixed x bj . The existence of such single-spin asymmetries requires a phase difference between two amplitudes coupling the proton target with J z p = ± 1 2 to the same final-state, the same amplitudes which are necessary to produce a nonzero proton anomalous magnetic moment. We show that the exchange of gauge particles between the outgoing quark and the proton spectators produces a Coulomb-like complex phase which depends on the angular momentum L z of the proton's constituents and thus is distinct for different proton spin amplitudes. The single-spin asymmetry which arises from such final-state interactions does not factorize into a product of structure function and fragmentation function, and it is not related to the transversity distribution δq(x, Q) which correlates transversely polarized quarks with the spin of the transversely polarized target nucleon.
Physical Review C, 2006
The cross sections for a variety of channels of proton-nucleus interaction associated with large ... more The cross sections for a variety of channels of proton-nucleus interaction associated with large gaps in rapidity are calculated within the Glauber-Gribov theory. We found inelastic shadowing corrections to be dramatically enhanced for such events. We employ the light-cone dipole formalism which allows to calculate the inelastic corrections to all orders of the multiple interaction. Although Gribov corrections are known to make nuclear matter more transparent, we demonstrate that in some instances they lead to an opaqueness. Numerical calculations are performed for the energies of the HERA-B experiment, and the RHIC-LHC colliders.
Physical Review D, 2010
The nucleon helicity-independent generalized parton distributions (GPDs) of quarks are calculated... more The nucleon helicity-independent generalized parton distributions (GPDs) of quarks are calculated in the zero skewness case, in the framework of the AdS/QCD model. The present approach is based on a matching procedure of sum rules relating the electromagnetic form factors to GPDs and AdS modes.
Journal of Physics G: Nuclear and Particle Physics, 1998
Two new sum rules for the quark tensor charges of the nucleon are proposed, based on a relation c... more Two new sum rules for the quark tensor charges of the nucleon are proposed, based on a relation connecting the quark transversity distributions to the quark helicity distributions and the quark model spin distributions, and on the sum rules for the quark helicity distributions. ...
Physical Review D, 1994
A beam of relativistic antihydrogen atoms-the bound state (Fe+)-can be created by circulating the... more A beam of relativistic antihydrogen atoms-the bound state (Fe+)-can be created by circulating the beam of an antiproton storage ring through an internal gas target . An antiproton that passes through the Coulomb field of a nucleus of charge 2 will create e+e-pairs, and antihydrogen will form when a positron is created in a bound rather than a continuum state about the antiproton. The -cross section for this process is calculated to be N 4Z2 pb for antiproton momenta above 6 GeV/c. The gas target of Fermilab Accumulator experiment E760 has already produced an unobserved N 34 antihydrogen atoms, and a sample of _ N 760 is expected in 1995 from the successor experiment E835. No other source of antihydrogen exists. A simple method for detecting relativistic antihydrogen ,is -proposed and a method outlined of measuring the antihydrogen Lamb shift .g-',. to N 1%.
We propose a novel mechanism for exclusive diffractive Higgs production pp → pHp in which the Hig... more We propose a novel mechanism for exclusive diffractive Higgs production pp → pHp in which the Higgs boson carries a significant fraction of the projectile proton momentum. This mechanism will provide a clear experimental signal for Higgs production due to the small background in this kinematic region. The key assumption underlying our analysis is the presence of intrinsic heavy flavor components of the proton bound state, whose existence at high light-cone momentum fraction x has growing experimental and theoretical support. We also discuss the implications of this picture for exclusive diffractive quarkonium and other channels.
A new scenario, alternative to energy loss, for the observed suppression of high-p T hadrons obse... more A new scenario, alternative to energy loss, for the observed suppression of high-p T hadrons observed at RHIC is proposed. In the limit of a very dense medium crated in nuclear collisions the mean free-path of the produced (pre)hadron vanishes, and and the nuclear suppression, R AA is completely controlled by the production length. The RHIC data are well explained in a parameter free way, and predictions for LHC are provided.
Arxiv preprint arXiv:1003.4188, 2010
We evaluate the shadowing effect in deeply virtual and real Compton scattering on nuclei in the f... more We evaluate the shadowing effect in deeply virtual and real Compton scattering on nuclei in the framework of the color dipole model. We rely on the soft photon wave function derived in the instanton vacuum model, and employ the impact parameter dependent phenomenological elastic dipole amplitude. Both the effects of quark and the gluon shadowing are taken into account.