Indonesia

M. Fauzi

Comment on “Strong lensing and shadow of Ayon-Beato–Garcia (ABG) nonsingular black hole”

We study nonsingular black holes viewed from the point of view of Ayon-Beato–Garcia (ABG) nonlinear electrodynamics (NLED) and present a complete study of their corresponding strong gravitational lensing. The NLED modifies the the photon’s geodesic, and our calculations show that such effect increases the corresponding photon sphere radius and image separation, but decreases the magnification. We also show that the ABG’s shadow radius is not compatible with bound estimates of Sgr A* from Keck and VLTI (Very Large Telescope Interferometer). Thus, the possibility of Sgr A* being a nonsingular ABG black hole is ruled out.

H. Ramadhan

M. Ishlah

F. Pratama

I. Alfredo

Strong lensing and shadow of Ayon-Beato–Garcia (ABG) nonsingular black hole

In this work, we study thermodynamics of generalized Ayon-Beato and Garcia (ABG) black hole metric which contains three parameters named as mass <math id="M1"><mi>m</mi></math>, magnetic charge <math id="M2"><mi>q</mi></math>, and dimensionless coupling constant of nonlinear electrodynamics interacting field <math id="M3"><mi>γ</mi></math>. We showed that central regions of this black hole behaves as dS (AdS) vacuum space by setting <math id="M4"><mi>q</mi><mo>&lt;</mo><mn>2</mn><mi>m</mi><mfenced><mrow><mi>q</mi><mo>&gt;</mo><mn>2</mn><mi>m</mi></mrow></mfenced></math> and in the case <math id="M5"><mi>q</mi><mo>=</mo><mn>2</mn><mi>m</mi></math> reaches to a flat Minkowski space. In the large distances, this black hole behaves as a Reissner-Nordstrom BH. However, an important role of the charge<math id="M6"><mi>q</mi></math> appeared in the production of a formal variable cosmological parameter which will support pressure coordinate in the thermodynamic perspective of this black hole in our setup. We should point that this formal variable cosmological parameter is different with cosmological constant which comes from AdS/CFT correspondence, and it is effective at large distances as AdS space pressure. In our setup, the assumed pressure originated from the internal material of the black hole say <math id="M7"><mi>q</mi></math> and <math id="M8"><mi>m</mi></math> here. By calculating the Hawking temperature of this black hole, we obtain equation of state. Then, we plotted isothermal P-V curves and heat capacity at constant pressure. They show that the system participates in the small to large phase transition of the black hole or the Hawking-Page phase transition which is similar to the van der Waals phase transition in the ordinary thermodynamics systems. In fact in the Hawking-Page phase transition disequilibrium, evaporating generalized ABG black hole reaches to a vacuum AdS space finally.

Iran

Hossein Ghaffarnejad

Elham Ghasemi

Thermodynamic Phase Transition of Generalized Ayon-Beato Garcia Black Holes

Abstract We discuss spontaneous chiral symmetry breaking and the quark bilinear condensate in large-N$_{c}$ quantum chromodynamics (QCD). It is known that the existence of the η′ meson is implied in large-N$_{c}$ QCD, as pointed out by Witten[27] and Veneziano[28]. First, we show that the existence of η′ and the Ward–Takahashi identities implies the existence of Nambu–Goldstone bosons from chiral symmetry breaking SU(N$_{f}$)$_{L}$ × SU(N$_{f}$)$_{R}$ → SU(N$_{f}$)$_{V}$. Second, we show that a QCD inequality implies a non-zero lower bound on the quark bilinear condensate.

Japan

Ryosuke Sato

Chiral symmetry breaking and the quark bilinear condensate in large- Qcd La Rivista del Nuovo Cimento Quarks and strings on a lattice

We study the orientifold projections of the <math><mi>N</mi><mo>=</mo><mn>1</mn></math> superconformal field theories describing D3-branes probing the Pseudo del Pezzo singularities PdP<math><msub><mrow></mrow><mrow><mn>3</mn><mi>b</mi></mrow></msub></math> and PdP<math><msub><mrow></mrow><mrow><mn>3</mn><mi>c</mi></mrow></msub></math>. The PdP<math><msub><mrow></mrow><mrow><mn>3</mn><mi>c</mi></mrow></msub></math> parent theory admits two inequivalent orientifolds. Exploiting a maximization, we find that one of the two has an a-charge smaller than what one would expect from the orientifold projection, which suggests that the theory flows to the fixed point in the infrared. Surprisingly, the value of a coincides with the charge of the unoriented PdP<math><msub><mrow></mrow><mrow><mn>3</mn><mi>b</mi></mrow></msub></math> and we interpret this as the sign of an infrared duality.

Italy

Andrea Antinucci

Salvo Mancani

Fabio Riccioni

Infrared duality in unoriented Pseudo del Pezzo

Motivated by understanding M2-branes, we propose to reformulate partition functions of M2-branes by quantum curves. Especially, we focus on the backgrounds of del Pezzo geometries, which enjoy Weyl group symmetries of exceptional algebras. We construct quantum curves explicitly and turn to the analysis of classical phase space areas and quantum mirror maps. We find that the group structure helps in clarifying previous subtleties, such as the shift of the chemical potential in the area and the identification of the overall factor of the spectral operator in the mirror map. We list the multiplicities characterizing the quantum mirror maps and find that the decoupling relation known for the BPS indices works for the mirror maps. As a result, with the group structure we can present explicitly the statement for the correspondence between spectral theories and topological strings on del Pezzo geometries.

Sanefumi Moriyama

Spectral theories and topological strings on del Pezzo geometries

We investigate the 
					 invariant mass distribution in the 
					 reaction at a center-of-mass energy of 
					 GeV measured by the BESIII collaboration, which concluded that no significant signals were observed for 
					 because of the low statistics. We show, however, that the 
					 invariant mass distribution is compatible with the existence of the 
					 state, appearing as a peak, and a strong cusp structure at the 
					 threshold, resulting from the molecular nature of the 
					 state, which provides a substantial contribution to the reaction. This is consistent with our previous analysis of the 
					 decay measured by the LHCb collaboration. We strongly suggest further measurements of this process with more statistics to clarify the nature of the 
					 and 
					 resonances.
				

China

En Wang

Ju-Jun Xie

Li-Sheng Geng

Spain

Eulogio Oset

The X(4140) and X(4160) resonances in the 
					 reaction Partly supported by the National Natural Science Foundation of China (11735003, 11522539, 11505158, 11475015, 11647601), supported by the Youth Innovation Promotion Association CAS (2016367), Key Research Projects of Henan Higher Education Institutions (20A140027), and the Academic Improvement Project of Zhengzhou University. This work is also partly supported by the Spanish Ministerio de Economia y Competitividad and European FEDER funds under the contract number FIS2014-57026-REDT, FIS2014-51948-C2-1-P, and FIS2014-51948-C2-2-P, the Generalitat Valenciana in the program Prometeo II2014/068, and the proyecto Severo Ochoa del IFIC, SEV-2014-0398.

We revisit a correspondence between toroidal compactifications of M-theory and del Pezzo surfaces, in which rational curves on the del Pezzo are related to <math><mfrac><mn>1</mn><mn>2</mn></mfrac></math>-BPS branes of the corresponding compactification. We argue that curves of higher genus correspond to nongeometric backgrounds of the M-theory compactifications, which are related to exotic branes. In particular, the number of “special directions” of the exotic brane is equal to the genus of the corresponding curve. In addition to predicting three new nongeometric backgrounds, we discuss a relation between addition of curves in the del Pezzo and the brane polarization effect.

United States

Justin Kaidi

Exotic branes from del Pezzo surfaces

Nonsingular Ayon-Beato-Garcia (ABG) spherically symmetric static black hole (BH) with charge to mass ratio <math id="M1"><mi>q</mi><mo>=</mo><mrow><mrow><mi>g</mi></mrow><mo>/</mo><mrow><mn>2</mn><mi>m</mi></mrow></mrow></math> is metric solution of Born Infeld nonlinear Maxwell-Einstein theory. Central region of the BH behaves as (anti-)de Sitter for <math id="M2"><mo>(</mo><mo>|</mo><mi>q</mi><mo>|</mo><mo>&gt;</mo><mn>1</mn><mo>)</mo><mo> </mo><mo> </mo><mo>|</mo><mi>q</mi><mo>|</mo><mo>&lt;</mo><mn>1</mn><mo>.</mo></math> In the case where <math id="M3"><mo>|</mo><mi>q</mi><mo>|</mo><mo>=</mo><mn>1</mn></math>, the BH central region behaves as Minkowski flat metric. Nonlinear Electromagnetic (NEM) fields counterpart causes deviation of light geodesics and so light rays will be forced to move on from effective metric. In this paper we study weak and strong gravitational lensing of light rays by seeking effects of NEM fields counterpart on image locations and corresponding magnification. We set our calculations to experimentally observed Sgr <math id="M4"><mrow><msup><mrow><mtext>A</mtext></mrow><mrow><mo>⁎</mo></mrow></msup></mrow></math> BH. In short we obtained the following: for large distances, the NEM counterpart is negligible and it reduces to linear Maxwell fields. The NEM field enlarges radius of the BH photon sphere linearly by raising <math id="M5"><mo>|</mo><mi>q</mi><mo>|</mo><mo>&gt;</mo><mn>1</mn></math> but decreases by raising <math id="M6"><mo>|</mo><mi>q</mi><mo>|</mo><mo>≤</mo><mn>1</mn><mo>.</mo></math> Sign of deflection angle of bending light rays is changed in presence of NEM effects with respect to ones obtained in absence of NEM fields. Absolute value of deflection angle rises by increasing <math id="M7"><mo>|</mo><mi>q</mi><mo>|</mo><mo>→</mo><mn>1</mn><mo>.</mo></math> Image locations in weak deflection limit (WDL) decrease (increases) by raising <math id="M8"><mn>0</mn><mo>&lt;</mo><mo>|</mo><mi>q</mi><mo>|</mo><mo>&lt;</mo><mn>1</mn></math> in presence (absence) of NEM fields. By raising the closest distance of the bending light rays image locations in WDL change from left (right) to right (left) in absence (presence) of NEM fields. In WDL, radius of Einstein rings and corresponding magnification centroid become larger (smaller) in presence (absence) of NEM fields. Angular separation called <math id="M9"><mrow><mi>s</mi></mrow></math> between the innermost and outermost relativistic images increases (decreases) by increasing <math id="M10"><mn>0</mn><mo>&lt;</mo><mo>|</mo><mi>q</mi><mo>|</mo><mo>&lt;</mo><mn>1</mn></math> in absence (presence) of NEM fields. Corresponding magnification <math id="M11"><mrow><mi>r</mi></mrow></math> decreases (increases) by raising <math id="M12"><mn>0</mn><mo>&lt;</mo><mo>|</mo><mi>q</mi><mo>|</mo><mo>&lt;</mo><mn>1</mn></math> in absence (presence) of NEM fields.

H. Ghaffarnejad

M. Amirmojahedi

H. Niad

Gravitational Lensing of Charged Ayon-Beato-Garcia Black Holes and Nonlinear Effects of Maxwell Fields

The dilepton invariant mass spectra and integrated branching ratios of the single and double Dalitz decays and (; or ) are predicted by means of a data-driven approach based on the use of rational approximants applied to and transition form factor experimental data in the space-like region.

Rafel Escribano

Sergi Gonzàlez-Solís

A data-driven approach to and single and double Dalitz decaysSupported by the FPI scholarship BES-2012-055371 (S.G-S), the Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya under grant 2014 SGR 1450, the Ministerio de Ciencia e Innovación under grant FPA2011-25948, the Ministerio de Economía y Competitividad under grants CICYT-FEDER-FPA 2014-55613-P and SEV-2012-0234, the Spanish Consolider-Ingenio 2010 Program CPAN (CSD2007-00042), and the European Commission under program FP7-INFRASTRUCTURES-2011-1 (283286) S.G-S also Received Support from the CAS President’s International Fellowship Initiative for Young International Scientist (2017PM0031)