Signatures of an invisibly decaying Higgs particles at LHC

The Higgs particle can decay dominantly into an invisible channel in the Majoron models. We have explored the prospect of detecting such a Higgs particle at LHC via its associated production with a gluon, Z or W boson. While the signal/background ratio is too small for the first process, the latter two provide viable signatures for detecting such a Higgs particle.Comment: (e-mail: [email protected]) LaTex; No. of pages 12, no. of figures 3 (available on request

Green chemistry approaches to the regioselective synthesis of spiro heterobicyclic rings using iodine as a new and efficient catalyst under solvent-free conditions

Iodine catalyzes the pseudo four-component reaction of an aldehyde, a urea or thiourea, and cyclic 1,3- dicarbonyl compounds under microwave irradiation in a solvent-free condition to yield various <3 symmetric spiro heterobicyclic rings in excellent yields

Large evolution of the bilinear Higgs coupling parameter in SUSY models and reduction of phase sensitivity

The phases in a generic low-energy supersymmetric model are severely constrained by the experimental upper bounds on the electric dipole moments of the electron and the neutron. Coupled with the requirement of radiative electroweak symmetry breaking, this results in a large degree of fine tuning of the phase parameters at the unification scale. In supergravity type models, this corresponds to very highly tuned values for the phases of the bilinear Higgs coupling parameter $B$ and the universal trilinear coupling $A_0$. We identify a cancellation/enhancement mechanism associated with the renormalization group evolution of $B$, which, in turn, reduces such fine-tuning quite appreciably without taking recourse to very large masses for the supersymmetric partners. We find a significant amount of reduction of this fine-tuning in nonuniversal gaugino mass models that do not introduce any new phases.Comment: Version to appear in Phys.Rev.D. Insignificant changes like a few typos corrected. 26 pages, 7 figures, LaTe

Ultrasonic assisted creep feed grinding of Inconel 718

AbstractThe paper details the effects of depth of cut and vibration amplitude when ultrasonic assisted (US) creep feed grinding Inconel 718 with an open structured alumina based wheel. The workpiece was actuated at a constant frequency (∼20.5kHz) via a block sonotrode attached to a 1kW piezoelectric transducer-generator system. A full factorial experimental array comprising 12 tests was conducted involving variation in depth of cut (0.1, 0.5 and 1.0mm), amplitude of vibration (high and low) and grinding condition (with and without vibration). Wheel speed and table feed were fixed at 30m/s and 600mm/min respectively for all tests. Application of ultrasonic vibration resulted in reductions in vertical (Fv) and horizontal (Fh) force components by up to 28% and 37% respectively, however greater wheel wear (30-60% lower G-ratio) occurred under hybrid operation due to increased grit/bond fracture. SEM micrographs of the slots machined with US assistance revealed higher levels of side flow/ploughing in comparison to standard creep feed ground specimens. Additionally, more overlapping grit marks were visible on surfaces subject to ultrasonic assisted grinding. Increasing amplitude of vibration produced lower grinding forces (up to 30% for Fv and 43% for Fh) but higher workpiece surface roughness (up to 24%). Topographic maps of grinding wheel surface replicas indicated that use of US vibration generally led to an increase in the number of active cutting points on the wheel

Measuring R-parity-violating couplings in dilepton production at the LHC

We revisit the issue of probing R-violating couplings of supersymmetric theories at hadronic colliders, particularly at the LHC. Concentrating on dimuon production, an evaluation of the optimal sensitivity to the R-violating coupling is performed through a maximum likelihood analysis. The measurement uncertainties are evaluated through a study of fully generated events processed through a fast simulation of the ATLAS detector. It is found that a host of R-violating couplings can be measured to a statistical accuracy of better than 10%, over a significant part of the m_{tilde f} -- lambda parameter space still allowed by low energy measurements. Since the bounds thus obtained do not simply scale as the squark mass, one can do significantly better at the LHC than at the Tevatron. The same analysis can also be extended to assess the reach of the LHC to effects due to any non-SM structure of the four-fermion amplitude, caused by exchanges of new particles with different spins such as leptoquarks and gravitons that are suggested by various theoretical ideas.Comment: 28 pages, 14 figures (uses JHEP3.cls

Study on Hydrographical Characteristics near the Luzon Strait

本论文基于Argo剖面资料、融合的卫星高度计资料、现场水文资料和数值模式OFES(由YukioMasumoto教授提供)的输出结果，分析吕宋海峡附近的水文特征。本论文的特色在于，我们揭示2008年秋季南海东北部一个反气旋涡的来源并展示其西传特征，以及探讨黑潮弯曲南部的气旋涡对黑潮南海分支和黑潮主轴的影响。 Argo剖面资料得到的2008年秋季20.5°N断面的温度、盐度分布态势与气候态秋季的分布基本一致。动力计算表明：Argo浮标剖面资料(选取1200m为速度零面)与融合的卫星高度计产品得到的20.5°N、117.5°～124.5°E断面的表层地转流北分量的分布比较吻合；吕宋海峡中部的黑潮主...The hydrographical characteristics near the Luzon Strait were analyzed by using Argo profiling floats dataset, merged altimeter data, in situ hydrographic data and OFES (ocean general circulation model for the Earth Simulation) outputs provided by Dr. Yukio Masumoto. We indicated that an anticyclonic eddy was generated in the interior SCS (South China Sea), and demonstrated that the anticyclonic e...学位：理学硕士院系专业：海洋与环境学院海洋学系_物理海洋学学号：2242007115082

Brane Dynamics in the Randall-Sundrum model, Inflation and Graceful Exit

We study the averaged action of the Randall-Sundrum model with a time dependent metric ansatz. It can be reformulated in terms of a Brans-Dicke action with time dependent Newton's constant. We show that the physics of early universe, particularly inflation, is governed by the Brans-Dicke theory. The Brans-Dicke scalar, however, quickly settles to its equilibrium value and decouples from the post-inflationary cosmology. The deceleration parameter is negative to start with but changes sign before the Brans-Dicke scalar settles to its equilibrium value. Consequently, the brane metric smoothly exits inflation. We have also studied the slow-roll inflation in our model and investigated the spectra of the density perturbation generated by the radion field and find them consistent with the current observations.Comment: Revised version, Accepted in Class. Quant. Gravit

A study on ultrasonic assisted creep feed grinding of nickel based superalloys

AbstractThe paper initially reviews research relating to ultrasonic (US) assisted grinding of various workpiece materials. Results from experimental trials to evaluate the influence of applying US vibration when creep feed grinding Inconel 718 with an open structured, alumina based grinding wheel (POROS 2) are then presented. A full factorial experimental array comprising 18 runs was conducted involving variation in wheel speed (30, 35 and 40m/s), table speed (200, 250 and 300mm/min) and grinding condition (with and without vibration). For tests with US vibration, the workpiece was actuated at a constant frequency (∼20kHz) via a specially designed block sonotrode attached to a 1kW piezoelectric transducer-generator system. Reductions in vertical (FV) and horizontal (FH) grinding force components of up to 23% and 43% for FV and FH respectively and surface roughness (Sa) of the ground slots by up to 45% were observed in the majority of tests when utilising US assisted operation. In terms of surface quality, SEM micrographs revealed greater side flow/ploughing and overlapping grit marks in slots machined with the workpiece vibrated in comparison to standard creep feed ground specimens. Three dimensional topographic measurement of grinding wheel surface replicas indicated that US vibration led to an increase in the number of active cutting points on the wheel