21 research outputs found

    Towards 1/N corrections to deep inelastic scattering from the gauge/gravity duality

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    1/N21/N^2 corrections to deep inelastic scattering (DIS) of charged leptons from glueballs at strong coupling are investigated in the framework of the gauge/gravity duality. The structure functions F1F_1 and F2F_2 (and also FLF_L) are studied at subleading order in the 1/N21/N^2 expansion, in terms of q2q^2 and the Bjorken parameter xx. The relevant type IIB supergravity one-loop diagrams (which correspond to DIS with two-hadron final states) are studied in detail, while nn-loop diagrams (corresponding to DIS with (n+1)(n+1)-hadron final states) are briefly discussed. The 1/N2n1/N^{2n} and Λ2/q2\Lambda^2/q^2 dependence of the structure functions is analyzed. Within this context two very different limits are considered: one is the large NN limit and the other one is when the virtual photon momentum transfer qq is much larger than the infrared confining scale Λ\Lambda. These limits do not commute.Comment: 45 page

    Deep inelastic scattering off scalar mesons in the 1/N expansion from the D3D7-brane system

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    Deep inelastic scattering (DIS) of charged leptons off scalar mesons in the 1/N expansion is studied by using the gauge/gravity duality. We focus on the D3D7-brane system and investigate the corresponding structure functions by considering both the high energy limit and the 1/N expansion. These limits do not commute. From the D7-brane DBI action we derive a Lagrangian at sub-leading order in the D7-brane fluctuations and obtain a number of interactions some of which become relevant for two-hadron final-state DIS. By considering first the high energy limit followed by the large N one, our results fit lattice QCD data within 1.27% for the first three moments of F 2 for the lightest pseudoscalar meson.Fil: Jorrin, David Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Kovensky, Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Schvellinger, Martín Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin

    Higher-twist fermionic operators and DIS structure functions from the AdS/CFT duality

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    The role of local higher-twist (τ>3) spin-1/2 fermionic operators of the strongly coupled N=4 supersymmetric Yang-Mills theory on the symmetric and antisymmetric deep inelastic scattering structure functions is investigated. The calculations are carried out in terms of the duality between N=4 SYM theory and type IIB supergravity on AdS5×S5. Particularly, we explicitly obtain the structure functions for single-trace spin-1/2 fermionic operators in the 20∗ and 60∗ irreducible representations of SU(4)R, corresponding to twists 4 and 5, respectively. We also calculate the contributions of other single-trace spin-1/2 fermionic operators in the 4, 20 and 60 irreducible representations of SU(4)R. New important effects are found in comparison with the minimal twist (τ=3) case, and they are studied thoroughly.Fil: Jorrin, David Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; ArgentinaFil: Schvellinger, Martín Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentin

    Física de hadrones y de plamas de quarks y gluones desde la dualidad AdS/CFT

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    En esta Tesis se investigan propiedades de dos sistemas fı́sicos cuyo denominador común es que su dinámica responde a la interacción fuerte, cuyo lagrangiano es el de la Cromodinámica Cuántica, pero que debido a que ambos sistemas se estudian en el régimen de acoplamiento fuerte,no es posible la utilización de las técnicas de la teorı́a de perturbaciones en el contexto de la Teorı́a Cuántica de Campos Relativista (TCC). Esto ofrece un escenario adecuado y muy interesante para el empleo de las técnicas basadas directamente en la dualidad entre las Teorı́as de Yang-Mills (TYM) por un lado, y la supergravedad (SUGRA) y la Teorı́a de Supercuerdas (TSC), por otro. Primeramente se investiga la estructura de glueballs de la Teorı́a de Yang-Mills supersimétrica (SYM) con N = 4 supersimetrı́as y grupo de gauge SU (Nc) en 3+1 dimensiones, ası́ como de mesones escalares de la teorı́a de gauge en 3+1 dimensiones con N = 2 supersimetrı́as. Eso se desarrolla en el contexto de la dispersión inelástica profunda (DIS) de leptones cargados por glueballs y mesones. Se calculan los tensores hadrónicos mediante el uso de sus correspondientes descripciones holográficas duales. Se desarrollan cálculos a one-loop en supergravedad del tipo IIB. En ambos casos se obtuvo un resultado central que consiste en que las expansiones en 1/Nc, por un lado, y en potencias de Λ^2 /q^2 , donde Λ es el cut-off IR de la TYM, mientras que q es el tetraimpulso transferido por el fotón virtual desde un leptón al hadrón (en el proceso DIS), por otro, no conmutan. Eso da como resultado que en el caso de los mesones escalares la comparación de los momentos de menor orden de las funciones de estructura mejoran sustancialmente el nivel de acuerdo con resultados desde Lattice QCD al considerar el lı́mite de altas energı́as y luego el lı́mite 1 << N c . En particular, para el pión los cálculos previos a nivel árbol cuya diferencia con Lattice QCD es del orden del 10 %, con los resultados de esta Tesis a nivel one-loop llegan al orden de aproximación del 1, 27 %. Asimismo, se obtuvieron nuevas relaciones del tipo de Callan-Gross. La segunda clase de sistemas fuertemente acoplados investigados corresponde a plasmas de quarks y gluones generados en colisiones ultra-relativistas de iones pesados en el Relativistic Heavy Ion Collider (RHIC, Broohaven, USA) y en el Large Hadron Collider (LHC, CERN, Suiza). Para el caso de las colisiones de iones de Au-Au y de Pb-Pb, en esta Tesis se desarrollan simulaciones numéricas considerando la descripción holográfica dual del plasma, desde la supergravedad del tipo IIB, en el caso de un agujero negro del tipo Schwarzschild asintóticamente AdS_5, considerando todas las correcciones en α´^3 , donde α´ = l_s^2 es decir el cuadrado de la longitud de la cuerda fundamental, a partir de la TSC del tipo IIB. Con esto se han obtenido curvas correspondientes a la emisión de fotones en dichos procesos y se ha comparado estos resultados directamente con resultados de los experimentos observando un mejor ajuste del espectro. Se obtuvieron coeficientes del flujo anisotrópico para colisiones de Au-Au en el rango de centralidad 0-20 % y 20-40 % en el mismo orden que los perturbativos indicando que posiblemente sea otras fuentes no consideradas que resuelven la tensión con los datos experimentales.Fil: Jorrin, David Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin

    Spin-1/2 fermionic operators of n=4 SYM theory and DIS from type IIB supergravity

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    We study deep inelastic scattering (DIS) of charged leptons from polarised spin1/2 hadrons in terms of the gauge/gravity duality. We calculate the structure functions related to spin-1/2 fermionic operators of N = 4 SYM theory in the planar limit and at strong coupling. Specifically, we focus on the twist-3 operator which is dual to a certain dilatino mode and gives the leading contribution to the hadronic tensor. We consider the Bjorken variable within the parametric range λ −1/2 SYM ≪ x < 1 where the supergravity dual description holds. From dimensional reduction of type IIB supergravity on the five-sphere, we derive the interaction terms involving two dilatini and a massless vector field mode. This vector field is a linear combination of certain components of the graviton and the four-form potential. The angular integrals on the five-sphere lead to selection rules for the interactions with important consequences on the dynamics. This implies the existence of new terms contributing to the structure functions that we explicitly calculate. The leading contribution comes from the Pauli term, followed by the contributions from the new terms we found.Fil: Jorrin, David Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Michalski, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Schvellinger, Martín Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin

    Proton helicity structure function g_1^p from a holographic Pomeron

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    We present a detailed analysis of the polarized and the unpolarized deep inelastic scattering structure functions of the proton, g_1^p and F_2^p respectively, in the context of a holographic dual description based on type IIB superstring theory. We compare this description with experimental data and Quantum Chromodynamics estimates computed at leading, next-to-leading and next-to-next-to-leading order in perturbation. We confront the predictions of a holographic dual model and those of perturbative QCD for g_1^p at the kinematics that will be probed by the forthcoming Electron-Ion Collider. We find that the extrapolation of g_1^p to very small values the Bjorken variable computed with a Holographic Pomeron model based on actual data at higher momentum fractions is always positive and differs significantly with standard projections based on perturbative QCD.Comment: 34 pages, 3 figure

    Deep inelastic scattering off scalar mesons in the 1/N expansion from the D3D7-brane system

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    Deep inelastic scattering (DIS) of charged leptons off scalar mesons in the 1/N expansion is studied by using the gauge/gravity duality. We focus on the D3D7-brane system and investigate the corresponding structure functions by considering both the high energy limit and the 1/N expansion. These limits do not commute. From the D7-brane DBI action we derive a Lagrangian at sub-leading order in the D7-brane fluctuations and obtain a number of interactions some of which become relevant for two-hadron final-state DIS. By considering first the high energy limit followed by the large N one, our results fit lattice QCD data within 1.27% for the first three moments of F2 for the lightest pseudoscalar meson.Instituto de Física La Plat

    Towards 1/N corrections to deep inelastic scattering from the gauge/gravity duality

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    1/N2 corrections to deep inelastic scattering (DIS) of charged leptons from glueballs at strong coupling are investigated in the framework of the gauge/gravity duality. The structure functions F1 and F2 (and also FL) are studied at subleading order in the 1/N2 expansion, in terms of q2 and the Bjorken parameter x. The relevant type IIB supergravity one-loop diagrams (which correspond to DIS with two-hadron final states) are studied in detail, while n-loop diagrams (corresponding to DIS with (n + 1)-hadron final states) are briefly discussed. The 1/N2n and Λ2/q2 dependence of the structure functions is analyzed. Within this context two very different limits are considered: one is the large N limit and the other one is when the virtual photon momentum transfer q is much larger than the infrared confining scale Λ. These limits do not commute.Facultad de Ciencias ExactasInstituto de Física La Plat

    Higher-twist fermionic operators and DIS structure functions from the AdS/CFT duality

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    The role of local higher-twist τ > 3 spin-1/2 fermionic operators of the strongly coupled N = 4 supersymmetric Yang-Mills theory on the symmetric and antisymmetric deep inelastic scattering structure functions is investigated. The calculations are carried out in terms of the duality between N = 4 SYM theory and type IIB supergravity on AdS₅ × S⁵. Particularly, we explicitly obtain the structure functions for single-trace spin-1/2 fermionic operators in the 20* and 60* irreducible representations of SU(4)R, corresponding to twists 4 and 5, respectively. We also calculate the contributions of other single-trace spin-1/2 fermionic operators in the 4, 20 and 60 irreducible representations of SU(4)R. New important effects are found in comparison with the minimal twist (τ = 3) case, and they are studied thoroughly.Facultad de Ciencias ExactasInstituto de Física La Plat

    Spin-1/2 fermionic operators of <i>N</i> = 4 SYM theory and DIS from type IIB supergravity

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    We study deep inelastic scattering (DIS) of charged leptons from polarised spin-1/2 hadrons in terms of the gauge/gravity duality. We calculate the structure functions related to spin-1/2 fermionic operators of N = 4 SYM theory in the planar limit and at strong coupling. Specifically, we focus on the twist-3 operator which is dual to a certain dilatino mode and gives the leading contribution to the hadronic tensor. We consider the Bjorken variable within the parametric range ; ; {\uplambda}_{\mathrm{SYM}}^{-1/2}\ll x<1 ; where the supergravity dual description holds. From dimensional reduction of type IIB supergravity on the five-sphere, we derive the interaction terms involving two dilatini and a massless vector field mode. This vector field is a linear combination of certain components of the graviton and the four-form potential. The angular integrals on the five-sphere lead to selection rules for the interactions with important consequences on the dynamics. This implies the existence of new terms contributing to the structure functions that we explicitly calculate. The leading contribution comes from the Pauli term, followed by the contributions from the new terms we found.Instituto de Física La Plat
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