SEMICLASSICAL VIOLATION OF THE EQUIVALENCE PRINCIPLE IN THE GRAVITATIONAL LENSES REALM

2009 ◽  
Vol 18 (14) ◽  
pp. 2107-2120 ◽  
Author(s):  
ANTONIO ACCIOLY ◽  
RICARDO PASZKO
Keyword(s):  
Cross Sections ◽  
Equivalence Principle ◽  
Deflection Angle ◽  
High Energy ◽  
Gravitational Lens ◽  
Massless Scalar ◽  
Gravitational Lenses ◽  
Scalar Boson ◽  
Classical Expression ◽  
The Impact

An expression for the gravitational deflection angle of a high-energy massless scalar boson is computed using the JWKB method. The resulting expression depends on the energy of the scalar boson or, equivalently, on its wavelength, even to first order in [Formula: see text], where G is Newton's constant, M is the mass of the gravitational source, and b is the impact parameter. On the other hand, combining the expressions for the magnification of two images obtained from a gravitational lens with the classical expression for the cross section, it is found that for purely gravitational scatterings the gravitational cross sections are proportional to the relative intensities. As a consequence of this remarkable proportionality and of the fact that the deflection angle obtained via the JWKB method is energy dependent, we come to the conclusion that chromatic effects in the gravitational lenses at the semiclassical level are possible, which violates the classical equivalence principle. The probability of detecting this tiny effect in the foreseeable future is discussed.

scholarly journals High Energy Rho Meson Leptoproduction §

2014 ◽  
Vol 1 (1) ◽  
pp. 33-35
Author(s):  
Adrien Besse ◽  
Lech Szymanowski ◽  
Samuel Wallon
Keyword(s):  
Cross Sections ◽  
Scattering Amplitude ◽  
Good Description ◽  
High Energy ◽  
Energy Limit ◽  
Rho Meson ◽  
Forward Limit ◽  
Helicity Amplitudes ◽  
Impact Parameter Space ◽  
The Impact

We investigate the longitudinal and transverse polarized cross-sections of the leptoproduction of the ρ meson in the high energy limit. Our model is based on the computation of the impact factor γ*(λγ)→ ρ (λρ) using the twist expansion in the forward limit which is expressed in the impact parameter space. This treatment involves in the final stage the twist 2 and twist 3 distribution amplitudes (DAs) of the ρ meson and the dipole scattering amplitude. Taking models that exist for the DAs and for the dipole cross-section. We get a phenomenological model for the helicity amplitudes. We compare our predictions with HERA data and get a fairly good description for large enough virtualities of the photon. PACS number(s): 13.60.Le, 12.39.St, 12.38.Bx.

scholarly journals Forbidden transitions in excitation by proton impact in Li-like Al ions

2007 ◽  
Vol 25 (2) ◽  
pp. 277-282 ◽  
Author(s):  
V. Stancalie ◽  
V. Pais ◽  
M. Totolici ◽  
A. Mihailescu
Keyword(s):  
Cross Sections ◽  
Born Approximation ◽  
High Energy ◽  
Impact Excitation ◽  
Proton Impact ◽  
Collision Strength ◽  
Energy Behavior ◽  
Forbidden Transitions ◽  
Excitation Processes ◽  
The Impact

This paper presents cross-sections and collision strengths for proton-impact excitation of optically forbidden transitions in Al10+. These data, calculated in the impact-parameter formalism, covering the expected range of energies/temperature in laser-produced plasmas, are believed to represent the first such detailed treatment of this system. The cross-sections decrease with energy as E−1, while the collision strengths tend to finite limits as the energy of colliding proton becomes infinitely great. This high-energy limiting value has been evaluated combining results from the semi-classical treatment of ion-impact excitation processes and the Born approximation for high-energy behavior of the collision strength. The effective target size has been estimated from the calculated high-energy limit of the collision strength in the Born approximation.

scholarly journals Some Recent Results on High-Energy Proton Interactions

Particles ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 57-69 ◽  
Author(s):  
I. M. Dremin
Keyword(s):  
Cross Sections ◽  
Scattering Amplitude ◽  
High Energy ◽  
Unitarity Condition ◽  
Total Cross Sections ◽  
Energy Proton ◽  
Elastic Scattering Amplitude ◽  
Energy Behavior ◽  
Impact Parameter Space ◽  
The Impact

Recent experimental results about the energy behavior of the total cross sections, the share of elastic and inelastic contributions to them, the peculiar shape of the differential cross section and our guesses about the behavior of real and imaginary parts of the elastic scattering amplitude are discussed. The unitarity condition relates elastic and inelastic processes. Therefore it is used in the impact-parameter space to get some information about the shape of the interaction region of colliding protons by exploiting new experimental data. The obtained results are described.

scholarly journals Measuring the Impact of Nuclear Interaction in Particle Therapy and in Radio Protection in Space: the FOOT Experiment

2021 ◽  
Vol 8 ◽  
Author(s):  
Giuseppe Battistoni ◽  
Marco Toppi ◽  
Vincenzo Patera ◽  
The FOOT Collaboration
Keyword(s):  
Cross Sections ◽  
Computational Models ◽  
Bragg Peak ◽  
Charged Particles ◽  
Absorbed Dose ◽  
High Energy ◽  
Particle Therapy ◽  
Main Concern ◽  
Nuclear Fragmentation ◽  
The Impact

In Charged Particle Therapy (PT) proton or 12C beams are used to treat deep-seated solid tumors exploiting the advantageous characteristics of charged particles energy deposition in matter. For such projectiles, the maximum of the dose is released at the end of the beam range, in the Bragg peak region, where the tumour is located. However, the nuclear interactions of the beam nuclei with the patient tissues can induce the fragmentation of projectiles and/or target nuclei and needs to be carefully taken into account when planning the treatment. In proton treatments, the target fragmentation produces low energy, short range fragments along all the beam path, that deposit a non-negligible dose especially in the first crossed tissues. On the other hand, in treatments performed using 12C, or other (4He or 16O) ions of interest, the main concern is related to the production of long range fragments that can release their dose in the healthy tissues beyond the Bragg peak. Understanding nuclear fragmentation processes is of interest also for radiation protection in human space flight applications, in view of deep space missions. In particular 4He and high-energy charged particles, mainly 12C, 16O, 28Si and 56Fe, provide the main source of absorbed dose in astronauts outside the atmosphere. The nuclear fragmentation properties of the materials used to build the spacecrafts need to be known with high accuracy in order to optimise the shielding against the space radiation. The study of the impact of these processes, which is of interest both for PT and space radioprotection applications, suffers at present from the limited experimental precision achieved on the relevant nuclear cross sections that compromise the reliability of the available computational models. The FOOT (FragmentatiOn Of Target) collaboration, composed of researchers from France, Germany, Italy and Japan, designed an experiment to study these nuclear processes and measure the corresponding fragmentation cross sections. In this work we discuss the physics motivations of FOOT, describing in detail the present detector design and the expected performances, coming from the optimization studies based on accurate FLUKA MC simulations and preliminary beam test results. The measurements planned will be also presented.

Investigating the impact of the partonic structure on the description of hadronic collisions at high energies

2020 ◽  
Vol 35 (22) ◽  
pp. 2050127
Author(s):  
M. Broilo ◽  
V. P. Gonçalves ◽  
P. V. R. G. Silva
Keyword(s):  
Cross Sections ◽  
High Energy ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Proton Proton ◽  
High Energies ◽  
High Energy Behavior ◽  
Energy Behavior ◽  
The Impact ◽  
Hadronic Collisions

The impact of the partonic structure on the description of the hadronic cross-sections is investigated considering a multichannel eikonal model based on the Good–Walker approach. The total, elastic and single diffractive cross-sections are estimated considering different parametrizations for the parton distribution functions and the predictions are compared with the experimental data for proton–proton [Formula: see text] and antiproton–proton [Formula: see text] collisions. We show that the description of the high-energy behavior of the hadronic cross-sections is sensitive to the partonic structure.

scholarly journals Insights on the impact of mitochondrial organisation on bioenergetics in high-resolution computational models of cardiac cell architecture

2018 ◽  
Author(s):  
Shouryadipta Ghosh ◽  
Kenneth Tran ◽  
Lea M. D. Delbridge ◽  
Anthony J. R. Hickey ◽  
Eric Hanssen ◽  
...  
Keyword(s):  
Cross Sections ◽  
Computational Models ◽  
Force Production ◽  
Creatine Phosphate ◽  
High Energy ◽  
Enzymatic Reactions ◽  
Force Dynamics ◽  
Significant Spatial Variation ◽  
Microscopy Data ◽  
The Impact

AbstractRecent electron microscopy data have revealed that cardiac mitochondria are not arranged in crystalline columns, but are organised with several mitochondria aggregated into columns of varying sizes often spanning the cell cross-section. This raises the question - how does the mitochondrial arrangement affect the metabolite distributions within cardiomyocytes and their impact on force dynamics? Here we employed finite element modelling of cardiac bioenergetics, using computational meshes derived from electron microscope images, to address this question. Our results indicate that heterogeneous mitochondrial distributions can lead to significant spatial variation across the cell in concentrations of inorganic phosphate, creatine (Cr) and creatine phosphate (PCr). However, our model predicts that sufficient activity of the creatine kinase (CK) system, coupled with rapid diffusion of Cr and PCr, maintains near uniform ATP and ADP ratios across the cell cross sections. This homogenous distribution of ATP and ADP should also evenly distribute force production and twitch duration with contraction. These results suggest that the PCr shuttle, and associated enzymatic reactions, act to maintain uniform force dynamics in the cell despite the heterogeneous mitochondrial organization. However, our model also predicts that under hypoxia - activity of mitochondrial CK enzyme and diffusion of high-energy phosphate compounds may be insufficient to sustain uniform ATP/ADP distribution and hence force generation.

scholarly journals γγ TOTAL CROSS-SECTION AT HIGH ENERGIES

2000 ◽  
Vol 15 (01) ◽  
pp. 9-13 ◽  
Author(s):  
C. BOURRELY ◽  
J. SOFFER ◽  
TAI TSUN WU
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
High Energy ◽  
Total Cross Sections ◽  
Energy Scattering ◽  
High Energies ◽  
High Energy Scattering ◽  
The Impact

We show that the rising total cross-sections σ(γγ→ hadrons) recently observed by the L3 and OPAL collaborations at LEP are fully consistent with the impact-picture for high-energy scattering. The impact picture is then used to predict this γγ total cross-section at higher energies, and confirm the universal increase of total cross-sections including those of pp, [Formula: see text] and γp.

scholarly journals Parton distributions in the SMEFT from high-energy Drell-Yan tails

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Admir Greljo ◽  
Shayan Iranipour ◽  
Zahari Kassabov ◽  
Maeve Madigan ◽  
James Moore ◽  
...  
Keyword(s):  
Cross Sections ◽  
Neutral Current ◽  
Light Quark ◽  
High Energy ◽  
New Physics ◽  
Effective Field ◽  
Distribution Functions ◽  
High Mass ◽  
Parton Distribution Functions ◽  
The Impact

Abstract The high-energy tails of charged- and neutral-current Drell-Yan processes provide important constraints on the light quark and anti-quark parton distribution functions (PDFs) in the large-x region. At the same time, short-distance new physics effects such as those encoded by the Standard Model Effective Field Theory (SMEFT) would induce smooth distortions to the same high-energy Drell-Yan tails. In this work, we assess for the first time the interplay between PDFs and EFT effects for high-mass Drell-Yan processes at the LHC and quantify the impact that the consistent joint determination of PDFs and Wilson coefficients has on the bounds derived for the latter. We consider two well-motivated new physics scenarios: 1) electroweak oblique corrections ($$ \hat{W},\hat{Y} $$ W ̂ , Y ̂ ) and 2) four-fermion interactions potentially related to the LHCb anomalies in R(K(*)). We account for available Drell-Yan data, both from unfolded cross sections and from searches, and carry out dedicated projections for the High-Luminosity LHC. Our main finding is that, while the interplay between PDFs and EFT effects remains moderate for the current dataset, it will become a significant challenge for EFT analyses at the HL-LHC.

The efficiency of application of virtual cross-sections method and hypotheses MELS in problems of wave signal propagation in elastic waveguides with rough surfaces

2016 ◽  
pp. 3564-3575 ◽  
Author(s):  
Ara Sergey Avetisyan
Keyword(s):  
Half Space ◽  
Cross Sections ◽  
Classical Method ◽  
Signal Propagation ◽  
Elastic Half Space ◽  
Layered Systems ◽  
Surface Layers ◽  
Inhomogeneous Surface ◽  
Wave Signal ◽  
The Impact

The efficiency of virtual cross sections method and MELS (Magneto Elastic Layered Systems) hypotheses application is shown on model problem about distribution of wave field in thin surface layers of waveguide when plane wave signal is propagating in it. The impact of surface non-smoothness on characteristics of propagation of high-frequency horizontally polarized wave signal in isotropic elastic half-space is studied. It is shown that the non-smoothness leads to strong distortion of the wave signal over the waveguide thickness and along wave signal propagation direction as well.  Numerical comparative analysis of change in amplitude and phase characteristics of obtained wave fields against roughness of weakly inhomogeneous surface of homogeneous elastic half-space surface is done by classical method and by proposed approach for different kind of non-smoothness.

scholarly journals A note on the relations between elastic and inelastic interactions and increasing ratio σel(s)/σtot(s) at the LHC

2019 ◽  
Vol 34 (32) ◽  
pp. 1950259 ◽  
Author(s):  
S. M. Troshin ◽  
N. E. Tyurin
Keyword(s):  
Elastic Scattering ◽  
Energy Dependence ◽  
Impact Parameter ◽  
Cross Sections ◽  
Parameter Dependence ◽  
Slope Parameter ◽  
Short Notice ◽  
Inelastic Interactions ◽  
The Impact ◽  
Mode A

We comment briefly on relations between the elastic and inelastic cross-sections valid for the shadow and reflective modes of the elastic scattering. Those are based on the unitarity arguments. It is shown that the redistribution of the probabilities of the elastic and inelastic interactions (the form of the inelastic overlap function becomes peripheral) under the reflective scattering mode can lead to increasing ratio of [Formula: see text] at the LHC energies. In the shadow scattering mode, the mechanism of this increase is a different one, since the impact parameter dependence of the inelastic interactions probability is central in this mode. A short notice is also given on the slope parameter and the leading contributions to its energy dependence in both modes.

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