arXiv subjects

R. M. Godbole

Publications and source records attributed to R. M. Godbole.

80 records · Page 5Linked to original sources

arXiv1994

Triplet Higgs bosons at $e^+e^-$ colliders

We investigate the possibility of probing the triplet Higgs boson sector via single charged Higgs production in the process $e^+ e^- \to H^+ l ν_l$, at high energy electron-positron colliders, using the tree level $H^+W^-Z$ coupling which is a unique feature of such models. We find that even LEP-200 can give nontrivial information upto $M_{H^{\pm}} \simeq 120 $ GeV if the doublet -triplet mixing is not restricted by the current value of the $ρ$ parameter which is the case in models with a custodial symmetry. Further we point out that in such models, the 4-body, tree level decay $H^+ \to W^*Z^* \to 4$ fermions dominates and hence provides a very clean signal when the four fermions are leptons. At NLC the discovery range for the charged Higgs in triplet models via this process is $\sim 400$ GeV.

hep-ph↗

arXiv1994

$γγ$ Processes at High Energy pp Colliders

In this note we investigate the production of charged heavy particles via \gaga\ fusion at high energy pp colliders. We revise previous claims that the \gaga\ cross section is comparable to or larger than that for the corresponding Drell-Yan process at high energies. Indeed we find that the \gaga\ contribution to the total production cross section at pp is far below the Drell-Yan cross section. As far as the individual elastic, semi-elastic and inelastic contributions to the \gaga\ process are concerned we find that they are all of the same order of magnitude.

hep-ph↗

arXiv1994

High Precision $J/ψ$ and $Υ$-production data and the Nuclear Glue

We use the high statistics E-772 data on the nuclear dependence of the production of quarkonia $(J/ψ$ and $Υ)$ and dimuons at large transverse momentum $(p_T)$ in $p$-$A$ collisions to get information about the gluonic EMC effect. We find a satisfactory quantitative agreement of the theoretical predictions with the data although none of the models of the EMC effect we consider could account for the entire data. Since all the qualitative features are understood none the less in terms of perturbative QCD with nuclear dependent parton densities, our results suggest that these data can now be used for a better determination of the nuclear parton densities. Our conslusions are shown to be insensitive to the hadronisation mechanism for the quarkonia.

hep-ph↗

arXiv1993

Higgs Search : Present and Future

In this talk I review theoretical bounds on mass of the Higgs scalar in the Standard Model(SM) and then summarise current experimental limits from the LEP experiments. Following this I discuss the search strategies for the SM Higgs at LEP 200 and the TeV energy \eplem\ colliders which are under discussion. This will be followed by a summary of the Higgs search potential of the pp supercolliders such as SSC/LHC. I then close with a brief discussion of a `Dark Higgs' whose dominant decay modes are into invisible channels.

hep-ph↗

arXiv1993

Sizing up the Nuclear Glue in $J/ψ$-production

Nuclear gluon densities are of great importance to the physics of relativistic heavy ion collisions, in particular, in assessing the origin of $J/ψ$-suppression. We describe our attempts to distinguish various models of the gluonic EMC-effect, using the existing $J/ψ$-production data in proton-nucleus collisions. We find that no model is capable of explaining {\em all} the features of the high precision E772 data although the overall trend suggests this to be more a matter of fine-tuning the models than the presence of new physical effects.

hep-ph↗

arXiv1993

Hard $γγ$ Collisions at Future $e^+ e^-$ LINACs

We update our previous calculation of di--jet production in two--photon collisions at future \ee\ colliders, including both beam-- and bremsstrahlung. We then discuss the production of heavy ($c,b,t$) quarks. Our study re--confirms that colliders with much beamstrahlung offer no physics advantages over designs with little beamstrahlung.

hep-ph↗

arXiv1992

Looking for the gluonic EMC effect in associated $J/ψ$ + $γ$ production

We study the associated production of $ J/ψ + γ$ in fixed-target experiments with nuclear targets as well as at the relativistic heavy-ion collider (RHIC). We find that this process affords a very clean probe of $ρ_g$, the ratio of gluon density in a heavy nucleus to that of a proton. The combined $x$ range thus available can be used to discriminate between the predictions of different models of the EMC effect for $ρ_g$.

hep-ph↗

arXiv1992

Aspects of Two-Photon Physics at Linear e+e- Colliders

We discuss various reactions at future e+e- and gamma-gamma colliders involving real (beamstrahlung or backscattered laser) or quasi--real (bremsstrahlung) photons in the initial state and hadrons in the final state. The production of two central jets with large pT is described in some detail; we give distributions for the rapidity and pT of the jets as well as the di--jet invariant mass, and discuss the relative importance of various initial state configurations and the uncertainties in our predictions. We also present results for `mono--jet' production where one jet goes down a beam pipe, for the production of charm, bottom and top quarks, and for single production of W and Z bosons. Where appropriate, the two--photon processes are compared with annihilation reactions leading to similar final states. We also argue that the behaviour of the total inelastic gamma-gamma cross section at high energies will probably have little impact on the severity of background problems caused by soft and semi--hard (`minijet') two--photon reactions. We find very large differences in cross sections for all two--photon processes between existing designs for future e+e- colliders, due to the different beamstrahlung spectra; in particular, both designs with <<1 and >>1 events per bunch crossing exist.

hep-ph↗