International Journal of Modern Physics A

We present a review of the recent theoretical and experimental developments related to the field of diffraction, parton saturation, and forward physics. We first discuss our present understanding of the proton structure in terms of quarks and gluons, the degrees of freedom of quantum chromodynamics. We then focus on some of the main results on diffraction at the HERA electron–proton collider in DESY, Germany, at the Tevatron proton–antiproton collider at Fermilab, Batavia, US, and at the CERN Large Hadron Collider (LHC) proton–proton and nucleus–nucleus collider, which is located in Geneva, Switzerland. We also present a selected amount of results on diffraction and photon exchanges that can be done at the LHC experiments and at a future Electron Ion Collider (EIC) to be built in the US at Brookhaven National Laboratory, New York.

We consider a two-parameter family of Drinfeld twists generated from a simple Jordanian twist further twisted by 1-cochains. Twists from this family interpolate between two simple Jordanian twists. Relations between them are constructed and discussed. It is proved that there exists a one-parameter family of twists identical to a simple Jordanian twist. The twisted coalgebra, star product and coordinate realizations of the $\kappa$-Minkowski noncommutative space–time are presented. Real forms of Jordanian deformations are also discussed. The method of similarity transformations is applied to the Poincaré–Weyl Hopf algebra and two types of one-parameter families of dispersion relations are constructed. Mathematically equivalent deformations, that are related to nonlinear changes of symmetry generators and linked with similarity maps, may lead to differences in the description of physical phenomena.

In Phys. Rev. Lett. 115, 143001 (2015), H. Mera et al. developed a new simple but precise hypergeometric resummation technique. In this work, we suggest to obtain half of the parameters of the hypergeometric function from the strong-coupling expansion of the physical quantity. Since these parameters are taking now their exact values they can improve the precision of the technique for the whole range of the coupling values. The second order approximant ${}_2{F}_1$ of the algorithm is applied to resum the perturbation series of the ground state energy of the ${𝒫}{𝒯}$-symmetric ${(i{\varphi }^3)}_{0+1}$ field theory. It gives accurate results compared to exact calculations from the literature specially for very large coupling values. The ${𝒫}{𝒯}$-symmetry breaking of the Yang–Lee model has been investigated where third, fourth and fifth orders were able to get very accurate results when compared to other resummation methods involving $150$ orders. The critical exponent $\nu$ of the $O(4)$-symmetric model in three dimensions has been precisely obtained using only first order of perturbation series as input. The algorithm can be extended easily to accommodate any order of perturbation series in using the generalized hypergeometric function ${}_{k+1}{F}_k$ as it shares the same analytic properties with ${}_2{F}_1$.

Morris and Thorne¹ proposed traversable wormholes, hypothetical connecting tools, using the concept of Einstein’s general theory of relativity. In this paper, the modification of general relativity (in particular $f(R,T)$ theory of gravity defined by Harko et al.²) is considered, to study the traversable wormhole solutions. The function $f(R,T)$ is considered as $f(R,T)=R+\alpha R^2+\beta T$, where $\alpha$ and $\beta$ are controlling parameters. The shape and redshift functions appearing in the metric of wormhole structure have significant contribution in the development of wormhole solutions. We have considered both variable and constant redshift functions with a logarithmic shape function. The energy conditions are examined, geometric configuration is analyzed and the radius of the throat is determined in order to have wormhole solutions in absence of exotic matter.

In this paper, we construct the $q$-deformed fuzzy Dirac and chirality operators on quantum fuzzy Podles sphere $S_{q\mu }^2$. Using the $q$-deformed fuzzy Ginsparg–Wilson algebra, we study the $q$-deformed gauged fuzzy Dirac and chirality operators in instanton sector. We will show the correct fuzzy sphere limit in the limit case $q\to 1$ and the correct commutative limit in the limit case when $q\to 1$ and noncommutative parameter $l$ tends to infinity.