Inelaticity in hadron-nucleus collisions from emulsion chamber studies

The inelasticity of hadron-carbon nucleus collisions in the energy region exceeding 100 TeV is estimated from the carbon-emulsion chamber data at Pamirs to be $= 0.65\pm 0.08$. When combined with the recently presented data on hadron-lead nucleus collisions taken at the same energy range it results in the $K\sim A^{0.086}$ mass number dependence of inelasticity. The evaluated partial inelasticity for secondary ($\nu > 1$) interactions, $K_{\nu >1} \simeq 0.2$, suggests that the second and higher interactions of the excited hadron inside the nucleus proceed with only slight energy losses.Comment: LaTeX file and 5 LaTeX files with figures, 11 pages altogether. Thoroughly rewritten and modified, one figure addded one removed. To be published in Phys. Rev.

Threshold Behaviour in Gauge Boson Pair Production at LEP 2

We discuss the form of the amplitude for gauge boson pair production at or near threshold.We show that in the case of W-pair production at LEP2 near threshold only one anomalous electromagnetic coupling can contribute. This anomalous coupling is CP violating and contributes to the electric dipole moment of the $W$. Since this coupling is likely to be small, it is important to look for ZZgamma couplings in Zgamma production. These couplings are not suppressed at the W-threshold

Static quantities of a neutral bilepton in the 331 model with right-handed neutrinos

A neutral vector boson can possess static electromagnetic properties provided that the associated field is no self-conjugate. This possibility is explored in the $SU_C(3) X SU_L(3) X U_N(1)$ model with right-handed neutrinos, which predicts a complex neutral gauge boson $Y^0$ in a nontrivial representation of the electroweak group. In this model the only nonvanishing form factors are the CP-even ones, which arise from both the quark and gauge sectors, and contribute to the magnetic dipole and the electric quadrupole moments of this neutral particle.Comment: 10 pages, 6 figures, submitted to Phys. Rev.

Note on CKM Matrix Renormalization

A simple inspection of the one loop quark self-energy suggests a prescription of the CKM matrix renormalization in the standard model. It leads to a CKM matrix counterterm which is gauge parameter independent and satisfies the unitarity constraint, and renormalized physical amplitudes which are gauge parameter independent and smooth in quark mass difference. We make a point that caution should be practiced when interpreting the CKM martix counterterm in terms of those of parameters in a given representation due to rephasing effects from renormalization. We show how this can be done using the degrees of freedom in the on-shell renormalization scheme.Comment: version 1: 10 pages, no figures; version 2: proofread version for Phys Rev D with minor revisions: (1) divided into 3 sections; (2) added a footnote Comment on Ref. [8] as Ref. item [13]; (3) typos fixed and minor rewordin

Renormalization of the Cabibbo-Kobayashi-Maskawa Quark Mixing Matrix

We have investigated the present renormalization prescriptions of Cabibbo-Kobayashi-Maskawa (CKM) matrix. When considering the prescription which is formulated with reference to the case of zero mixing we find it doesn't satisfy the unitary condition of the bare CKM matrix. After added a delicate patch this problem can be solved at one-loop level. In this paper We generalize this prescription to all loop levels and keep the unitarity of the bare CKM matrix, simultaneously make the amplitude of an arbitrary physical process involving quark mixing convergent and gauge independent. We also find that in order to keep the CKM counterterms gauge independent the unitarity of the bare CKM matrix must be preserved.Comment: has been revised, 8 pages, 1 figur

Electroweak Corrections to the Top Quark Decay

We have calculated the one-loop electroweak corrections to the decay t-> bW+, including the counterterm for the CKM matrix elements V(tb). Previous calculations used an incorrect delta V(tb) that led to a gauge dependent amplitude. However, since the contribution stemming from delta V(tb) is small, those calculations only underestimate the width by roughly one part in 10^5.Comment: 7 pages, 2 figure

Interior comfort regulation with gypsum plasters

In this work, the performance of a manually applied thin layer of a multilayer gypsum plaster system, for interior lining of walls and ceilings, incorporating phase change materials (PCM), is investigated. The study aims the development of a passive solar storage system that can be combined with both active heating and cooling storage systems and equipments. Mechanical and thermal tests were carried in laboratory, in two test cells and in residential buildings. Results so far showed that the gypsum plaster with 20%-wt. PCM reduces up to 45-50% flexural and compressive strengths, but the specifications of the European standard for these materials are fulfil. On what concerns thermal properties, the use of gypsum-PCM plaster reduces the maximum room temperature up to 5 ºC with a time delay of 3 hours and increases the minimum room temperature up to 1.5 ºC with a time delay of 2 hours. Besides, it also reduces room relative humidity up to 10%. Power savings of 0.44 W/m2wall.m2floor were estimated, with higher potential for lower temperatures, according to tests carried in a Passy’s test cell during the cooling season.Agência de Inovação (ADI

Properties of gypsum-PCM based mortars for interior plastering of construction systems

Incorporating phase change materials (PCM) in plasters is an effective solution both for more efficient use of energy and its consumption reduction, because it allows the use of free energy in the environment, by latent heat storage. As PCM has not binder properties, it is expected to decrease mechanical properties of the final mortar. Also the density of the mortar decreases due to PCM lighter specific weight. In order to be used as a final coat for wall plastering, it must verify the requirements of the respective European Standard. This paper presents the results of the composition development and mechanical properties (flexural, compressive and adhesive strengths) testing and validation of three different gypsum mortars, in order to select the appropriate one for thermal testing in test cells. The results show that the effective decrease in the studied characteristics of the mortar does not inhibit the use for plastering, as requirements are achieved by the three studied compositions.Agência de Inovação (ADI