arXiv subjects

Saurabh Niyogi

Publications and source records attributed to Saurabh Niyogi.

21 records · Page 2Linked to original sources

arXiv2012

Non-minimal Universal Extra Dimensions: The strongly interacting sector at the Large Hadron Collider

We work out the strongly interacting sector of a non-minimal Universal Extra Dimension (nmUED) scenario with one flat extra spatial dimension orbifolded on S^1/Z_2 in the presence of brane-localized kinetic and Yukawa terms. On compactification, these terms are known to have significant, nontrivial impact on the masses and the couplings of the Kaluza-Klein (KK) excitations. We study the masses of the level `1' KK gluon and the quarks and find the modified strong interaction vertices involving these particles. The scenario conserves KK parity. Possibility of significant level-mixing among the quarks from different KK-levels is pointed out with particular reference to the top quark sector. Cross sections for various generic final states involving level `1' KK-gluon and KK-quarks from first two generations are estimated at the Large Hadron Collider (LHC) via an implementation of the scenario in MadGraph-5 with the help of FeynRules. The decay branching fractions of both strong and weakly interacting KK excitations are studied to estimate yields in various different final states involving jets, leptons and missing energy. These are used to put some conservative constraints on the nmUED parameter space using the latest LHC data. Nuances of the scenario are elucidated with reference to the minimal Universal Extra Dimension (mUED) and Supersymmetry (SUSY) and their implications for the LHC are discussed.

hep-ph↗

arXiv2012

Constraints on invisible Higgs decay in MSSM in the light of diphoton rates from the LHC

We examine the parameter space of the purely phenomenological minimal super- symmetric standard model (MSSM), without assuming any supersymmetry breaking scheme. We find that a large region of the parameter space can indeed yield the lightest neutral Higgs mass around 125 GeV, as suggested by the recent ATLAS data, and also lead to event rates around, or slightly higher than, the standard model expectation in the two-photon and four-lepton channels. Using a lightest neutralino that is considerably lighter than the Higgs, we find that the 'invisible' decay of the Higgs into a pair of neutralinos upto about 10% can be consistent with the current data from the Large Hadron Collider (LHC).

hep-ph↗

arXiv2011

Entangled System of Squarks from the Third Generation at the Large Hadron Collider

In the Minimal Supersymmetric extension of the Standard Model (MSSM) squarks from the third generation, i.e., the bottom and the top squarks, have a common set of parameters that determine their masses and couplings. These are in the form of the common soft mass for the left handed squark from the third generation ($m_{\widetilde{Q}_{_{3L}}}$), the supersymmetry conserving Higgsino mass parameter $μ$ and $\tanβ$, the ratio of vacuum expectation values of the two Higgs doublets. This leads to an interesting possibility that the systems involving the bottom and the top squarks might get correlated in a non-trivial way even in an unconstrained setup. In this work, phenomenology of the bottom and the top squarks is studied at the Large Hadron Collider which exploits such a possibility with a particular emphasis on bottom squark decaying to top squark and $W$ boson. Possibility of reconstructing multiple $W$ bosons in the final state is identified to be the key in probing the squark mixing angles. Further entanglement of the electroweak gaugino-higgsino sector is also not impossible in scenarios based on phenomenological MSSM while for highly constrained scenarios like minimal supergravity/constrained MSSM such entanglements are trivially forced upon.

hep-ph↗