Testing the AMSB Model via e+e−→χ~+χ~−γe^+e^- \to \tilde{\chi}^+ \tilde{\chi}^- \gamma}

The possibility of detecting the signature of a nearly invisible charged wino (\CH) decaying into a soft pion and the LSP(\LSP), predicted by the Anomaly Mediated Symmetry Breaking model, via the process $e^+e^-\r\gamma{\tilde\chi}^{+}{\tilde\chi}^{-}$ at the Next Linear Collider has been explored. Using the recently, proposed bounds on slepton and wino masses derived from the condition of stability of the electroweak symmetry breaking vacuum and employing some standared kinematical cuts to supress the background, we find that almost the whole of the allowed parameter space with the slepton mass less than 1 TeV, can be probed at $\sqrt{s}$ 500 GeV. Determination of the slepton and the chargino masses from this signal is a distinct possiblity. Any violation of the above mass bound will suggest that the standard vacuum is unstable and we are living in a false vacuum.Comment: 10pages, Latex style, 4 figs, revised versio

On the Observability of "Invisible" / "Nearly Invisible" Charginos

It is shown that if the charginos decay into very soft leptons or hadrons + $\not{E}$ due to degeneracy/ near- degeneracy with the LSP or the sneutrino, the observability of the recently proposed signal via the single photon (+ soft particles) + $\not{E}$ channel crucially depends on the magnitude of the \SNU mass due to destructive interferences in the matrix element squared. If the \SNU's and, consequently, left-sleptons are relatively light, the size of the signal, previously computed in the limit \MSNU \to \infty only, is drastically reduced. We present the formula for the signal cross section in a model independent way and discuss the observability of the signal at LEP 192 and NLC energies.Comment: 27 pages, Late

Signatures of the Light Down-Squark Scenario at the Upgraded Tevatron

In scenarios with relatively light down squarks, motivated, e.g., by SO(10) D terms, jets + missing $E_T$ signals can be observed at the luminosity upgraded Tevatron even if the squarks are much heavier than the gluinos and the common gaugino mass ($M_{{1/2}}$) at $M_G$ lies above the LEP allowed lower bound. In the conventional mSUGRA model with heavy squarks practically no signal is expected in this channel. The possiblity of distinguishing between various SUGRA motivated scenarios by exploiting the missing $E_T$ and jet $p_T$ distributions, opposite sign dileptons + jets + missing $E_T$ events and clean trilepton signals have been discussed.Comment: 14 pages, 3 ps figure

Preferential Adsorption of CO₂ in an Ultramicroporous MOF with Cavities Lined by Basic Groups and Open-Metal Sites

Here, we present a new ultramicroporous Cu₂ paddlewheel based MOF. This ultramicroporous MOF has most of the features such as porosity (BET surface area = 945 m²/g), CO₂ capacity (3.5 mmol/g at ambient temperature and pressure), CO₂/N₂ selectivity (sCO₂/N₂ = 250), and fast CO₂ diffusion kinetics (<i>D</i>_c = 2.25 × 10^–9 m²/s), comparable to some of the other high-performing ultramicroporous MOFs, with strong binding sites. Typically, such MOFs exhibit strong CO₂–framework interactions (evidenced from a heat of adsorption ≥ 38 kJ/mol). However, the MOF explained here, despite having channels lined by the amine and the open-metal sites, possesses only a moderate CO₂–framework interaction (HOA = 26 kJ/mol). Using periodic DFT, we have probed this counterintuitive observation