A New Layered Iron Fluorophosphates

A new iron fluorophosphate of the composition, [C6N4H21] [Fe2F2(HPO4)3][H2PO4]·2H2O, I. has been prepared by the hydrothermal route. This compound contains iron fluorophosphate layers and the H2PO4- anions are present in the interlayer space along with the protonated amine and water molecules. The compound crystallizes in the monoclinic space group P21/c. (a = 13.4422(10) Å, b = 9.7320(10) Å, c = 18.3123(3) Å, ? = 92.1480°, V = 2393.92(5) Å3, Z = 4, M = 719.92, dcalc. = 1.997 g cm-3, R1 =. 0.03 and wR2 = 0.09)

Gluino mass limits with sbottom NLSP in coannihilation scenarios

In view of the recent interest in the pMSSM with light third generation squarks, we consider a hitherto neglected scenario where the lighter bottom squark ($\widetilde{b}_1$) is the next lightest supersymmetric particle (NLSP) which co-annihilates with the lightest supersymmetric particle (LSP), the dark matter (DM) candidate. Since the co-annihilation cross section receives contributions from both electroweak and strong vertices, it is relatively large. As a result relatively large NLSP-LSP mass difference (25 - 35 GeV) is consistent with the PLANCK data. This facilitates the LHC signatures of this scenario. We consider several variants of the sbottom NLSP scenario with and without light stops and delineate the parameter space allowed by the PLANCK data. We point out several novel signal (e.g., $\widetilde{t}_1 \rightarrow \widetilde{b}_1 W$) which are not viable in the stop NLSP scenario of DM production. Finally, we consider gluino ($\widetilde g$) decays in this scenario and using the current ATLAS data in the jets (with or without b-tagging) + $\not \!\! E_T$ channel, obtain new limits in the $m_{\widetilde{b}_1} - m_{\widetilde g}$ mass plane. We find that for $m_{\widetilde{b}_1}$ upto 500 GeV, $m_{\widetilde g} \geq$ 1.1 - 1.2 TeV in this scenario.Comment: 21 pages, 4 figures, few references added; published in JHE

Reduced LHC constraints for higgsino-like heavier electroweakinos

As a sequel to our earlier work on wino-dominated $\tilde \chi_1^{\pm}$ and $\tilde \chi_2^{0}$ (wino models), we focus on the pMSSM models where $\tilde \chi_1^{\pm}$ and $\tilde \chi_{2,3}^{0}$ are either higgsino dominated (higgsino models) or admixtures of significant amount of higgsino and wino components (mixed models), with or without light sleptons. The LHC constraints in the trilepton channel are significantly weaker even in the presence of light sleptons, especially in the higgsino models, compared to those mostly studied by the LHC collaborations with wino-dominated $\tilde \chi_1^{\pm}$ and $\tilde \chi_2^{0}$. The modes $\tilde \chi_{2,3}^{0}\rightarrow h~\tilde\chi_1^{0}$ with large branching ratios (BRs) are more common in the higgsino models and may produce spectacular signal in the LHC Run-II. In a variety of higgsino and mixed models we have delineated the allowed parameter space due to the LHC constraints, the observed Dark Matter (DM) relic density of the universe, which gets contributions from many novel DM producing mechanisms i.e., the annihilation/coannihilation processes that lead to the correct range of relic density, and the precise measurement of the anomalous magnetic moment of the muon. In the higgsino models many new DM producing mechanisms, which are not allowed in the wino models, open up. We have also explored the prospects of direct and indirect detection of DM in the context of the LUX and IceCube experiments respectively. In an extended model having only light gluinos in addition to the electroweak sparticles, the gluinos decay into final states with multiple taggable b-jets with very large BRs. As a consequence, the existing ATLAS data in the $0l$ + jets (3b) + $E\!\!\!\!/_T$ channel provide the best limit on $m_{\tilde g}$ ($\approx$ 1.3 TeV). Several novel signatures of higgsino models for LHC Run-II and ILC have been identified.Comment: 55 pages, 13 figures, 10 tables. Version published in JHE

Phosphorous Acid Route Synthesis of Iron Tavorite Phases, LiFePO₄(OH)ₓF₁₋ₓ [0 ≤ X ≤ 1] and Comparative Study of Their Electrochemical Activities

New synthesis routes were employed for the synthesis of three derivatives of iron hydroxo-, fluoro-, and mixed hydroxo-fluoro phosphates LiFePO 4(OH)xF1-x where 0 ? x ? 1 with the tavorite structure type, and their detail electrochemical activities have been presented. The hydrothermal synthesis of the pure hydroxo-derivative, LiFePO4OH, using phosphorous acid as a source of phosphate yielded good quality crystals from which the crystal structure was solved for the first time using SC-XRD (single crystal X-ray diffraction). The fluoro derivative, LiFePO4F, was prepared as a very fine powder at low temperature in a solvent-less flux-based method employing phosphorous acid and mixed alkali metal nitrates. A mixed anionic hydroxo-fluoro iron tavorite phase, LiFePO 4(OH)0.32F0.68, was also synthesized by a hydrothermal route. The electrochemical performance of the three phases was studied with galvanostatic charge-discharge tests, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). All three phases showed facile Li-insertion through the reduction of Fe3+ to Fe2+ at an average voltage in the range of 2.4-2.75 V, through the variation of the anion from pure OH to pure F. An increase of 0.35 V was observed as a result of F substitution in the OH position. Also, good cyclability and capacity retention were observed for all three phases and a reversible capacity of more than 90% was achieved for LiFePO4F. The results of EIS indicated that lithium ion mobility is highest in the mixed anion

The Electroweak Sector of the pMSSM in the Light of LHC - 8 TeV and Other Data

Using the chargino-neutralino and slepton search results from the LHC in conjunction with the WMAP/PLANCK and $(g-2)_{\mu}$ data, we constrain several generic pMSSM models with decoupled strongly interacting sparticles, heavier Higgs bosons and characterized by different hierarchies among the EW sparticles. We find that some of them are already under pressure and this number increases if bounds from direct detection experiments like LUX are taken into account, keeping in mind the associated uncertainties. The XENON1T experiment is likely to scrutinize the remaining models closely. Analysing models with heavy squarks, a light gluino along with widely different EW sectors, we show that the limits on gluino mass are not likely to be below 1.1 TeV, if a multichannel analysis of the LHC data is performed. Using this light gluino scenario we further illustrate that in future LHC experiments the models with different EW sectors can be distinguished from each other by the relative sizes of the $n$-leptons + $m$-jets + {\mbox{{E\!\!\!\!/_T}}} signals for different choices of $n$.Comment: 52 pages, 14 figures; few references added; published in JHE

Right ventricular involvement and conduction disturbances in acute inferior wall myocardial infarction patients and their angiographic correlation

Background: Right ventricular myocardial infarction (RVMI) in the setting of inferior wall myocardial infarction (IWMI) is associated with adverse events. The study aimed to evaluate right ventricular (RV) systolic function in the first episode of IWMI by echocardiography; determine incidence of different conduction abnormalities during hospitalization in IWMI patients with and without RVMI; and determine association of these parameters with the location of significant lesion in the infarct related artery.Methods: This was a prospective study conducted from March 2014 to February 2015. Patients diagnosed with a first episode of acute ST-segment elevation IWMI who presented within 12 hours of symptom onset participated in the study. Patients were divided into two groups according to location of myocardial infarction based on electrocardiographic (ECG) findings. Four echocardiographic parameters of RV systolic function: tricuspid annular plane systolic excursion (TAPSE); systolic excursion velocity of lateral tricuspid annulus (S'); myocardial performance index by pulsed Doppler method (MPI-PD); and right ventricular fraction area change (RV-FAC) were measured.Results: Clinical presentation such as Kussmaul sign (<0.05), hypotension (<0.05), and raised jugular venous pressure (<0.05) were higher in the IWMI+RVMI group than the IWMI group. ECG-based criteria, ST elevation in V4R to predict RVMI revealed 78.84% sensitivity, 88.86% and 87.46% positive predictive value (p<0.05). TAPSE (13.44±1.46 versus 21.0±1.16 mm, p<0.05), S’ (9.03±1.51 versus 16.26±1.21 cm/sec, p<0.05) and RV-FAC (31.24±3.15 versus 47.17±3.65%, p<0.05) were lower in the IWMI+RVMI group compared to the IWMI group.Conclusions: Cut-off values of TAPSE, S’, MPI-PD, and RV-FAC have high sensitivity and specificity for predicting proximal right coronary artery lesions.

A Polymorph of K₄Ge₄Se₁₀

A new monoclinic polymorph, ?-K4Ge4Se10 (tetra-potassium deca-selenidotetra-germanate), that crystallizes in space group P21/c has been isolated. The structure contains isolated super-tetra-hedral adamantane [Ge4Se10]4- clusters identical to those in the known K4Ge4Se10 polymorph (P21/m), held together in in the crystal structure by ionic inter-action with the K+ ions. The adamantane unit, [Ge4Se10] 4-, is formed by corner-sharing of four GeSe4 tetra-hedra, with average Ge -. Se distances of 2.378 and 2.281 Å for (Ge - Se)endo and (Ge - Se)exo, respectively. There are four crystallographically distinct K + ions in ?-K4Ge4Se10 having coordination numbers of 5, 7. and 8 ( 2), with K - Se distances in the range 2.986 (2)-3.888 (1) Å, while the coordination numbers of the three unique K+ ions in the known K4Ge4Se10 (P21/m) vary between 5. and 7. Besides the differences in coordination numbers of K+ ions, the two polymorphs also exhibit a. different packing of the adamantane units

New limits on top squark NLSP from ATLAS 4.7 fb−1fb^{-1} data

Using the ATLAS 4.7 $fb^{-1}$ data on new physics search in the jets + \met channel, we obtain new limits on the lighter top squark ($\tilde t_1$) considering all its decay modes assuming that it is the next to lightest supersymmetric particle (NLSP). If the decay \lstop \ra c \lspone dominates and the production of dark matter relic density is due to NLSP - LSP co-annihilation then the lower limit on \mlstop is 240 GeV. The limit changes to 200 GeV if the decay \lstop \ra b W \lspone dominates. Combining these results it follows that \lstop NLSP induced baryogenesis is now constrained more tightly.Comment: 9 pages, 2 figures, published in MPL