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M. J. Menon

Publications and source records attributed to M. J. Menon.

47 records · Page 3Linked to original sources
arXiv2002

Analyticity Relations at High Energies and Forward Scattering

Making use of a derivative dispersion approach, we investigate the behavior of the the total cross section and the rho parameter for pp and p(bar)p scattering from accelerator to cosmic ray energies. The discrepancies in the cosmic ray information is treated through the definition of two different ensembles of data. Simultaneous and individual fits to the above quantities through the Donnachie-Landshof and Kang-Nicolescu parametrizations allows to infer an upper bound for the intercept of the soft Pomeron and also show that the data investigated do not favor the Odderon hypothesis.

hep-ph↗
arXiv2001

High-Energy Proton-Proton Forward Scattering and Derivative Analyticity Relations

We present the results of several parametrizations to two different ensemble of data on $pp$ total cross sections $σ_{tot}^{pp}$ at the highest center-of-mass energies (including cosmic-ray information). The results are statistically consistent with two distinct scenarios at high energies. From one ensemble the prediction for the LHC ($\sqrt s = 14$ TeV) is $σ_{tot}^{pp} = 113 \pm 5$ mb and from the other, $σ_{tot}^{pp}=140 \pm 7$ mb. From each parametrization, and making use of derivative analyticity relations (DAR), we determine $ρ(s)$ (ratio between the forward real and imaginary parts of the elastic scattering amplitude). A discussion on the optimization of the DAR in terms of a free parameter is also presented.In all cases good descriptions of the experimental data are obtained.

hep-ph↗
arXiv2001

On the total cross section extrapolations to cosmic-ray energies

We analyze $pp$ total cross section data from accelerator to cosmic-ray energies and show that the experimental information presently available indicate two different scenarios at the highest energies. One of them accommodates the predictions of the majority of models and the other one shows agreement with a multiple diffraction model recently developed and improved. We argue that these results may bring a kind of warning against some possible precipitated attempts to constraint cosmic-ray estimations from analyzes of accelerator data.

hep-ph↗
arXiv1999

Hadronic and elementary multiplicity distributions in a geometrical approach

We construct the hadronic multiplicity distribution in terms of an elementary distribution (at given impact parameter) and the inelastic overlap function characterized by the observed BEL (Blacker-Edgier-Larger) behaviour. With suitable parametrizations for the elementary quantities, based on some geometrical arguments and the most recent data on e+e- annihilation, an excellent description of pp and p(bar)p inelastic multiplicity distributions at the highest energies is obtained.

hep-ph↗
arXiv1999

Scaling violations: Connections between elastic and inelastic hadron scattering in a geometrical approach

Starting from a short range expansion of the inelastic overlap function, capable of describing quite well the elastic pp and $\bar{p}p$ scattering data, we obtain extensions to the inelastic channel, through unitarity and an impact parameter approach. Based on geometrical arguments we infer some characteristics of the elementary hadronic process and this allows an excellent description of the inclusive multiplicity distributions in $pp$ and $\bar{p}p$ collisions. With this approach we quantitatively correlate the violations of both geometrical and KNO scaling in an analytical way. The physical picture from both channels is that the geometrical evolution of the hadronic constituents is principally reponsible for the energy dependence of the physical quantities rather than the dynamical (elementary) interaction itself.

hep-ph↗
arXiv1999

Differential dispersion relations and elementary amplitudes in a multiple diffraction model

We discuss the evaluation of the real part of the elementary amplitudes in the context of a multiple diffraction model for $pp$ elastic scattering earlier developed. The framework is based on the concepts of analyticity and polynomial boundedness, and the techniques of dispersion relations. Novel results concern the use of derivative dispersion relations at the elementary level (constituent-constituent interactions) and an optimization of these relations in terms of one free parameter. In addition to a theoretical improvement, we achieved a satisfactory description of the physical quantities.

hep-ph↗
arXiv1998

A conjecture on centauro species

It is argued that Centauro events observed in cosmic ray experiments may be characteristic of only pp and not p(bar)p interactions.

hep-ph↗
arXiv1998

High energy parton-parton amplitudes from lattice QCD and the stochastic vacuum model

Making use of the gluon gauge-invariant two-point correlation function, recently determined by numerical simulation on the lattice in the quenched approximation and the stochastic vacuum model, we calculate the elementary (parton-parton) amplitudes in both impact-parameter and momentum transfer spaces. The results are compared with those obtained from the Krämer and Dosch ansatz for the correlators. Our main conclusion is that the divergences in the correlations functions suggested by the lattice calculations do not affect substantially the elementary amplitudes. Phenomenological and semiempirical information presently available on elementary amplitudes is also referred to and is critically discussed in connection with some theoretical issues.

hep-ph↗
arXiv1997

Evidence for eikonal zeros in the momentum transfer space

We present the results of fitting elastic $pp$ differential cross section data at 23.5 $\leq \sqrt{s} \leq$ 62.5 GeV with a novel analytic parametrization for the scattering amplitude. Making use of a fitting method, the errors from the free parameters are propagated to the imaginary part of the eikonal in the momentum transfer space. A novel systematic study of the effects coming from data at large momentum transfer is also performed. We find statistical evidence for the existence of eikonal zeros in the interval of momentum transfer 5-9 $GeV^{2}$.

hep-ph↗
arXiv1997

Multiple diffraction model for proton-proton elastic scattering and total cross section extrapolations to cosmic-ray energies

We analyse pp elastic scattering data at the highest accelerator energy region (between 10 and 63 GeV) through a multiple diffraction approach. The use of Martin's formula in a model developed earlier is substituted by the introduction of a complex elementary (parton-parton) amplitude. With this the total cross section and the real part of the hadronic amplitude may be simultaneously investigated and, with the exception of the diffraction minimum at some ISR energies, a satisfactory description of all experimental data is obtained. Total cross sections extrapolations to cosmic-ray energies (above 6 TeV) show agreement with the reanalysis of the Akeno data performed by N. N. Nikolaev and also with Gaisser, Sukhatme and Yodh results, leading to the prediction 147 mb for the total cross section at 16 TeV. Physical interpretations and critical remarks concerning our parametrizations and results are also presented and discussed.

hep-ph↗