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Henrique Boschi-Filho

Publications and source records attributed to Henrique Boschi-Filho.

At least 55 records · Page 3Linked to original sources
arXiv2018

Deconfinement phase transition in a magnetic field in 2+1 dimensions from holographic models

Using two different models from holographic quantum chromodynamics (QCD) we study the deconfinement phase transition in $2+1$ dimensions in the presence of a magnetic field. Working in 2+1 dimensions lead us to {\sl exact} solutions on the magnetic field, in contrast with the case of 3+1 dimensions where the solutions on the magnetic field are perturbative. As our main result we predict a critical magnetic field $B_c$ where the deconfinement critical temperature vanishes. For weak fields meaning $B B_c$ we find that the critical temperature raises with growing field showing a magnetic catalysis (MC). These results for IMC and MC are in agreement with the literature.

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arXiv2017

Entanglement Entropy for D3-, M2- and M5-brane backgrounds

In the context of the gauge/gravity duality applications, we study and compute the entanglement entropy of gauge theories corresponding to string/M theories on D3-, M2- and M5-brane backgrounds. This is achieved using the Ryu-Takayanagi formula. We obtain the entanglement entropy for the general cases of the D3-, M2- and M5-brane backgrounds and also for the near horizon AdS limit, as well as the non-conformal flat space limit in each case.

hep-th↗
arXiv2017

Effective holographic models for QCD: glueball spectrum and trace anomaly

We investigate effective holographic models for QCD arising from five dimensional Dilaton-Gravity. The models are characterized by a dilaton with a mass term in the UV, dual to a CFT deformation by a relevant operator, and quadratic in the IR. The UV constraint leads to the explicit breaking of conformal symmetry whereas the IR constraint guarantees linear confinement. We propose semi-analytic interpolations between the UV and the IR and obtain a spectrum for scalar and tensor glueballs consistent with lattice QCD data. We use the glueball spectrum as a physical constraint to find the evolution of the model parameters as the mass term goes to zero. Finally, we reproduce the universal result for the trace anomaly of deformed CFTs and propose a dictionary between this result and the QCD trace anomaly. A nontrivial consequence of this dictionary is the emergence of a $β$ function similar to the two-loop perturbative QCD result.

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arXiv2017

A Study of confinement for $Q\bar{Q}$ potentials on D3, M2 & M5 branes

We study analytically and numerically the interaction potentials between a pair of quark an anti-quark on D3, M2 and M5 branes. These potentials are obtained using Maldacena's method involving Wilson loops and present confining and non-confining behaviours in different situations that we explore in this work. In particular, at the near horizon geometry the potentials are non-confining in agreement with conformal field theory expectations. On the other side, far from horizon, the dual field theories are no longer conformal and the potentials present confinement. This is in agreement with the behaviour of strings in flat space where the string mimics the expected flux tube of QCD. A study of the transition between the confining/non-confining regimes in the three different scenarios (D3, M2, M5) is also performed.

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arXiv2017

Twist Two Operator Approach for Even Spin Glueball Masses and Pomeron Regge Trajectory from the Hardwall Model

We compute the masses of even spin glueball states $ J^{PC} $, with $ P=C=+1 $, using a twist two operator from an AdS/QCD model known as the hardwall model, using Dirichlet and Neumann boundary conditions. Within this approach, we found that the glueball masses are comparable with those in literature. From these masses, we obtained the Pomeron Regge trajectories for both boundary conditions in agreement with experimental data available and other holographic models.

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arXiv2016

Pomeron and Odderon Regge Trajectories from a Dynamical Holographic Model

In this work we use gauge/string dualities and a dynamical model that takes into account dynamical corrections to the metric of the anti de Sitter space due to a quadratic dilaton field and calculate the masses of even and odd spin glueball states with $P=C=+1$, and $P=C=-1$, respectively. Then we construct the corresponding Regge trajectories which are associated with the pomeron for even states with $P=C=+1$, and with the odderon for odd states with $P=C=-1$. We compare our results with those coming from experimental data as well as other models.

hep-ph↗
arXiv2016

Dynamical corrections to the anomalous holographic softwall model: the pomeron and the odderon

In this work we use the holographic softwall AdS/QCD model with anomalous dimension contributions coming from two different QCD beta functions to calculate the masses of higher spin glueball states for both even and odd spins and its respective Regge trajectories, related to the pomeron and the odderon, respectively. We further investigate this model taking into account dynamical corrections due to a dilaton potential consistent with Einstein equations in 5 dimensions. The results found in this work for the Regge trajectories within the anomalous softwall model with dynamical corrections are consistent with those presented in the literature.

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arXiv2015

Glueball spectra and Regge trajectories from a modified holographic softwall model

In this work we propose a modified holographic softwall model, analytically solvable, to calculate the masses of lightest scalar glueball and its radial excitations and of higher spin glueball states for both even and odd spins. From these results we obtain their respective Regge trajectories, associated with the pomeron for even spins and with the odderon for odd spins. These results are in agreement with those calculated using other approaches.

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arXiv2015

Deep Inelastic Scattering in the Exponentially Small Bjorken Parameter Regime from the Holographic Softwall Model

We use the AdS/CFT correspondence and the holographic softwall model to investigate the Deep Inelastic Scattering (DIS) in the exponentially small $x$ (Bjorken Parameter) regime. We calculate the corresponding structure functions for scalar fields. Using these results we studied the problem of the saturation line in the strong interactions. Our results are consistent with those achieved using other models.

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arXiv2015

Wilson Loops for M2- and M5-brane spaces

We calculate configuration energies of string-like membranes in M2- and M5-brane spaces. In the near horizon approximation these backgrounds reduce to $AdS_4\times S^7$ and $AdS_7\times S^4$ spaces and the dual theories are supersymmetric $SU(N)$ gauge theories, in accordance with the AdS/CFT correspondence. In this case the string-like configuration energy is identified with the quark and anti-quark energy interaction in the dual theories. Far from the horizon the dual theory is more involved but any how we were able to calculate the string-like configuration energy. For limiting regimes we find simpler solutions for which some potentials exhibit a confinement behavior while others are non-confining.

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arXiv2015

The Blackbody Radiation Laws in the $ \textrm{AdS}_5 \times {\cal S}^5 $ Spacetime

In the footsteps of our previous work \cite{RamatonBoschi} we generalize the Stefan-Boltzmann and Wien's displacement laws for the $ \textrm{AdS}_5 \times {\cal S}^5 $ spacetime, the background of the AdS/CFT correspondence foremost realization. Our results take into account the $ \textrm{AdS}_5 \times {\cal S}^5 $ full dimensionality in the electromagnetic field $A^μ$ wave equation, which yields the higher-dimensional blackbody characteristic features suggested in literature. In particular, the total radiated power and the spectral radiancy match the original Stefan-Boltzmann and Wien's displacement laws in the low-energy regime up to available experimental data.

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arXiv2014

The Size of Compact Extra Dimensions from Blackbody Radiation Laws

In this work we generalize the Stefan-Boltzmann and Wien's displacement laws for a $D$-dimensional manifold composed by 4 non-compact dimensions and $D-4$ compact dimensions, $ R^{1,3}$ x $T^{D-4} $. The electromagnetic field is assumed to pervade all compact and non-compact dimensions. In particular, the total radiated power becomes $ R(T) = σ_B T^4 + σ_D (a) \, T^D $, where $a$ is the size of the compact extra dimensions. For $D=10$, predicted from String Theory, and $D=11$, from M-Theory, the outcomes agree with available experimental data for $a$ as high as 2 x $10^{-7}$m.

hep-th↗
arXiv2013

Vector meson quasinormal modes in a finite-temperature AdS/QCD model

We study the spectrum of vector mesons in a finite temperature plasma. The plasma is holographically described by a black hole AdS/QCD model. We compute the boundary retarded Green's function using AdS/CFT prescriptions. The corresponding thermal spectral functions show quasiparticle peaks at low temperatures. Then we calculate the quasinormal modes of vector mesons in the soft-wall black hole geometry and analyse their temperature and momentum dependences.

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arXiv2012

Towards Relativistic Skyrmions

We revisit baryons in the Skyrme model. Starting from static baryons in the helicity eigenstates, we generalize their wavefunctions to the non-static and relativistic regime. A new representation for gamma matrices in the soliton collective space is constructed and the corresponding Dirac equation is obtained. As an example, we draw consideration on how to apply this new representation on the calculus of vector current vacuum expectation values for baryon states of spin and isospin half and arbitrary momenta and we show how elastic form factors can be derived.

hep-th↗
arXiv2012

Production of negative parity baryons in the holographic Sakai-Sugimoto model

We extend our investigation of resonance production in the Sakai-Sugimoto model to the case of negative parity baryon resonances. Using holographic techniques we extract the generalized Dirac and Pauli baryon form factors as well as the helicity amplitudes for these baryonic states. Identifying the first negative parity resonance with the experimentally observed S_{11}(1535), we find reasonable agreement with experimental data from the JLab-CLAS collaboration. We also estimate the contribution of negative parity baryons to the proton structure functions.

hep-ph↗
arXiv2012

Generalized baryon form factors and proton structure functions in the Sakai-Sugimoto model

We investigate the production of positive parity baryon resonances in proton electromagnetic scattering within the Sakai-Sugimoto model. The latter is a string model for the non-perturbative regime of large $N_c$ QCD. Using holographic techniques we calculate the generalized Dirac and Pauli form factors that describe resonance production. We use these results to estimate the contribution of resonance production to the proton structure functions. Interestingly, we find an approximate Callan-Gross relation for the structure functions in a regime of intermediate values of the Bjorken variable.

hep-ph↗
arXiv2012

Electromagnetic scattering of vector mesons in the Sakai-Sugimoto model

In this proceeding we review some of our recent results for the vector meson electromagnetic form factors and structure functions in the Sakai-Sugimoto model. The latter is a string model that describes many features of the non-perturbative regime of Quantum Chromodynamics in the large $N_c$ limit.

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