Method of frustrated total reflection in spectroscopy of surface polaritons in almost perfectly conducting metals

The standard technique for surface polaritons excitation by a prism coupling in Otto configuration is applied for investigation of almost perfectly conducting (pec) metals like tantalum irradiated by a collimated He-Ne laser radiation (λ ₀ = 632.8 nm). In pec metals the imaginary part of the relative dielectric permittivity (ɛ″) is quite larger than the modulus of the real part of the same quantity (ɛ′ < 0, ɛ″ ≫ | ɛ′ |). Under this condition the single Lorentz dip of the reflectivity coefficient is proven to exist and is given in an analytical form, which follows from simplification of the usual multilayer Fresnel formula. In the case of a deterministically curved metal surface an approximate solution to the reduced Rayleigh integral equation appropriate for the Otto configuration is also given. These two theoretical deductions are compared with experimental data that have been produced by us for the reflectivity into the prism region from a bulk tantalum sample.     

The coherent K L 0 C → K S 0 C regeneration at high energies

New experimental results on the coherentK _L ⁰ C K _S ⁰ C regeneration in the momentum range 10p30 GeV/c are presented. For the quantity (f ₀–¯f ₀/k (where f₀ and¯f ₀ are theKC and¯K ⁰C forward scattering amplitudes andk is the wave number) we have obtained: arg (f ₀–¯f ₀)/k=–126±14 and ¦(f ₀–¯f ₀/k¦ p ^{–0.62±0.14} These results are well described by a simple Regge pole model including only the (-trajectory exchange in thet-channel with the intercept (0) close to 0.4.Presented at the IV International Symposium on High Energy and Elementary Particle Physics, Warszaw, September 1975.     

KL0-KS0 transmission regeneration on hydrogen

The energy dependence of the modulus and phase of the K_L⁰-K_S⁰ regeneration amplitude on hydrogen in the range of 14–50 GeV has been investigated at the Serpukhov 70 GeV accelerator.It has been established that the modulus of the modified regeneration amplitude decreases with increasing momentum as $\text{2|?}{}_{21}{}^0\text{(p)|/k = (0.84 ± 0.42) · p}{}^{\mathrm{?0.50\pm 0.15}}\text{mb}$. The amplitude phase is energy-independent and its mean value is ?₂₁⁰ = ?132° ± 5°. The results obtained are compared with other experiments and with predictions of different theoretical models.     

A Single‐Molecule Perspective on the Role of Solvent Hydrogen Bonds in Protein Folding and Chemical Reactions

We present an array of force spectroscopy experiments that aim to identify the role of solvent hydrogen bonds in protein folding and chemical reactions at the single‐molecule level. In our experiments we control the strength of hydrogen bonds in the solvent environment by substituting water (H₂O) with deuterium oxide (D₂O). Using a combination of force protocols, we demonstrate that protein unfolding, protein collapse, protein folding and a chemical reaction are affected in different ways by substituting H₂O with D₂O. We find that D₂O molecules form an integral part of the unfolding transition structure of the immunoglobulin module of human cardiac titin, I27. Strikingly, we find that D₂O is a worse solvent than H₂O for the protein I27, in direct contrast with the behaviour of simple hydrocarbons. We measure the effect of substituting H₂O with D₂O on the force dependent rate of reduction of a disulphide bond engineered within a single protein. Altogether, these experiments provide new information on the nature of the underlying interactions in protein folding and chemical reactions and demonstrate the power of single‐molecule techniques to identify the changes induced by a small change in hydrogen bond strength.     

Nuclear structure functions in carbon nearx=1

Data from deep inelastic scattering of 200 GeV muons on a carbon target with squared four-momentum transfer 52 GeV²Q ²200 GeV² were analysed in the region of the Bjorken variable close tox=1, which is the kinematic limit for scattering on a free nucleon. At this value ofx, the carbon structure function is found to beF ₂ ^C 1.2·10^–4. Thex dependence of the structure function forx>0.8 is well described by an exponentialF ₂ ^C exp(–sx) withs=16.5±0.6.Deceased     

Low frequency longitudinal waves in argon hot cathode discharges. I

Experimental investigation of low-frequency longitudinal waves in argon low-current thermionic cathode discharges at the pressure from 10 Pa to 100 Pa is described. The longitudinal waves are generated in the discharge volume forpd _ac Pa. cm if the thermionic emission-discharge current ratio,I _em/I _d, is greater than 30.     

Study of nuclear effects in nucleon structure functions up to and beyond the kinematic limit

An experiment on deep inelastic muon nucleon scattering in order to study the x-dependence of nucleon structure functions and their ratios over a range ofQ ²=50–200 GeV² andx= =0·4–2·0 is proposed. Such measurements performed on a number of nuclei with atomic weights from 2 to 207 provide new information for detailed studies of the EMC effect and test models explaining thex-behaviour of the nucleon structure functions and their ratios. The measurements are decisive for the proof that a quark-parton model of the nucleus describes adequately nuclear structure probed at high energies. The upgraded high luminosity BCDMS spectrometer with improved resolution in transferred energy can be used for the measurements.Dedicated to the 30th anniversary of the Joint Institute for Nuclear Research.     

Search for a standard model Higgs boson in CMS via vector boson fusion in the H→WW→lνlν channel

We present the potential for discovering the standard model Higgs boson produced via the vector-boson fusion mechanism. We considered the decay of Higgs bosons to the W⁺W^- final state, with both W-bosons subsequently decaying leptonically. The main background is tt̄ produced in association with one or more jets. This study is based on a full simulation of the CMS detector. The result is that a signal of 5σ significance can be obtained with an integrated luminosity of 12–72 fb^-1 for Higgs boson masses in the range 130<m_H< 200 GeV. In addition, the major background can be measured directly to 7% from the data with an integrated luminosity of 30 fb^-1. We also suggest a method to determine the Higgs mass using template transverse mass distributions. PACS 14.80.Bn