Deciphering Universal Extra Dimension from the top quark signals at the CERN LHC

Models based on Universal Extra Dimensions predict Kaluza-Klein (KK) excitations of all Standard Model (SM) particles. We examine the pair production of KK excitations of top- and bottom-quarks at the Large Hadron Collider. Once produced, the KK top/bottom quarks can decay to $b$-quarks, leptons and the lightest KK-particle, $\gamma_1$, resulting in 2 $b$-jets, two opposite sign leptons and missing transverse momentum, thereby mimicing top-pair production. We show that, with a proper choice of kinematic cuts, an integrated luminosity of 100 fb$^{-1}$ would allow a discovery for an inverse radius upto $R^{-1} = 750$ GeV.Comment: 18 pages, 14 figures, Accepted for publication in JHE

Entangling two Bose Einstein condensates in a double cavity system

We propose a scheme to transfer the quantum state of light fields to the collective density excitations of a Bose Einstein condensate (BEC) in a cavity. This scheme allows to entangle two BECs in a double cavity setup by transferring the quantum entanglement of two light fields produced from a nondegenerate parametric amplifier (NOPA) to the collective density excitations of the two BECs. An EPR state of the collective density excitations can be created by a judicious choice of the system parameters.Comment: 3 figure

Post-flight Analysis and Design Improvement in Command Guidance System for a Short-range Surface-to-air Missile System

A short-range missile with command-to line-of-sight and three-beam guidance has been considered in this paper. The earlier command guidance system (CGS) design shows unacceptablyhigh-low-frequency weave-mode oscillations, leading to high latax and body rate oscillations, even for benign, low-speed non-manoeuvring target engagements. For successful targetengagements with the three-beam guidance, missile is to be handed over from wide-to-medium receiver beam, and finally, from medium-to-the most accurate narrow receiver beam, depending on the angular error wrt line-of-sight as early as possible. Due to large amplitude oscillation in the earlier CGS design, the handing over of the missile to narrow receiver beam, and in many cases, to the medium receiver beam, itself could not take place, leading to failure of guidance. In this paper, the cause for this undesirable high magnitude weave-mode oscillation has been analysed in detail. After establishing this, saturation aspects of the earlier CGS design; a simple implementable CGS re-design was carried out to reduce this saturation aspect drastically for preserving almost full-phase advance effects of the linear new analogue compensators designed to give the required stability margins of guidance loop

Search for Higgs bosons of the Universal Extra Dimensions at the Large Hadron Collider

The Higgs sector of the Universal Extra Dimensions (UED) has a rather involved setup. With one extra space dimension, the main ingredients to the construct are the higher Kaluza-Klein (KK) excitations of the Standard Model Higgs boson and the fifth components of the gauge fields which on compactification appear as scalar degrees of freedom and can mix with the former thus leading to physical KK-Higgs states of the scenario. In this work, we explore in detail the phenomenology of such a Higgs sector of the UED with the Large Hadron Collider (LHC) in focus. We work out relevant decay branching fractions involving the KK-Higgs excitations. Possible production modes of the KK-Higgs bosons are then discussed with an emphasis on their associated production with the third generation KK-quarks and that under the cascade decays of strongly interacting UED excitations which turn out to be the only phenomenologically significant modes. It is pointed out that the collider searches of such Higgs bosons face generic hardship due to soft end-products which result from severe degeneracies in the masses of the involved excitations in the minimal version of the UED (MUED). Generic implications of either observing some or all of the KK-Higgs bosons at the LHC are discussed.Comment: 25 pages, 9 figures and 1 tabl

Hypervalent Iodine(III) promoted ring-rearrangement strategies in conformationally rigid ring systems

The ring-rearrangement reactions are among the important class of atom economic chemical transformations as it involves direct construction of carbocylic or heterocyclic rings through bond migration reactions. The usefulness of such operation has been realized by many publications [1] and applications in the field of organic synthesis, medicinal chemistry, natural product synthesis and chemical biology [2]. Moreover, the inclusion of environmental benign hypervalent iodine(III) reagents in such processes allows to design a milder pathway to achieve desired ring-rearrangement reactions [3]. Herein, in the present context we have demonstrated a milder pathway for hypervalent iodine(III) mediated ring contraction of conformationally rigid exocyclic-β-enaminones for the synthesis of cyclopentanones with concurrent cyanation [4]. Furthermore, the synthesized cyclopentanones serves as a basic template for the synthesis of new class of ∂-valerolactams by the applications of hypervalent iodine reagents [5].The work was supported by the Russian Science Foundation grant 19-73-10144 and RFBR grant 18-03-00715

CD33M inhibits microglial phagocytosis, migration and proliferation, but the Alzheimer’s disease‐protective variant CD33m stimulates phagocytosis and proliferation, and inhibits adhesion

Funder: Biotechnology and Biological Sciences Research Council; Id: http://dx.doi.org/10.13039/501100000268Abstract: CD33 is a Siglec (sialic acid‐binding immunoglobulin‐type lectin) receptor on microglia. Human CD33 can be alternatively spliced into two isoforms: the long isoform (CD33M) and a shorter isoform (CD33m) that lacks the sialic acid‐binding site. CD33m appears to protect against Alzheimer's disease; however, it remains unclear how. To investigate potential mechanisms by which CD33m may confer protection, we expressed the CD33m and CD33M isoforms of human CD33 in mouse BV‐2 and human CHME3 microglial cells and assessed microglia functions. In the BV‐2 cells, CD33M inhibited microglial phagocytosis of beads, synapses, debris and dead cells, while CD33m increased phagocytosis of beads, debris and cells. RNAi knockdown of the endogenous mouse CD33 increased phagocytosis and prevented CD33m's (but not CD33M’s) effect on phagocytosis. CD33M increased cell attachment but inhibited cell proliferation, while CD33m did the opposite. We also found that CD33M inhibited cell migration. In human CHME3 cells, CD33M increased cell attachment, but inhibited phagocytosis, proliferation and migration, whereas CD33m did the opposite. We conclude that CD33M inhibits microglial phagocytosis, inhibits migration and increases adhesion, while CD33m increases phagocytosis, proliferation and inhibits adhesion. Thus, CD33m might protect against Alzheimer's disease by increasing microglial proliferation, movement and phagocytosis of debris and dead cells. imag

Constraining Bosonic Supersymmetry from Higgs results and 8 TeV ATLAS multi-jets plus missing energy data

The collider phenomenology of models with Universal Extra Dimensions (UED) is surprisingly similar to that of supersymmetric (SUSY) scenarios. For each level-1 bosonic (fermionic) Kaluza-Klein (KK) state, there is a fermionic (bosonic) analog in SUSY and thus UED scenarios are often known as bosonic supersymmetry. The minimal version of UED (mUED) gives rise to a quasi-degenerate particle spectrum at each KK-level and thus, can not explain the enhanced Higgs to diphoton decay rate hinted by the ATLAS collaboration of the Large Hadron Collider (LHC) experiment. However, in the non-minimal version of the UED (nmUED) model, the enhanced Higgs to diphoton decay rate can be easily explained via the suitable choice of boundary localized kinetic (BLK) terms for higher dimensional fermions and gauge bosons. BLK terms remove the degeneracy in the KK mass spectrum and thus, pair production of level-1 quarks and gluons at the LHC gives rise to hard jets, leptons and large missing energy in the final state. These final states are studied in details by the ATLAS and CMS collaborations in the context of SUSY scenarios. We find that the absence of any significant deviation of the data from the Standard Model (SM) prediction puts a lower bound of about 2.1 TeV on equal mass excited quarks and gluons.Comment: 19 page