Mjerenje radijativne širine lakih pseudoskalarnih mezona na 11 GeV promakoffovim efektom

The spontaneous breaking of chiral symmetry and the chiral anomalies in low-energy QCD are manifested in their most unambiguous form in the light pseudoscalar mesons sector. Understanding the electromagnetic properties of these mesons are, therefore, crucial for probing QCD at the confinement scale. The study of two-photon decay widths of the π 0 , η, and η ′ are of fundamental importance in determining mixing effects among the mesons and in obtaining the light-quark mass ratios. The PrimEx collaboration at Jefferson Lab has a comprehensive program to perform a high precision measurement of the π 0 → γγ decay width via the Primakoff effect. With the planned 11 GeV upgrade of CEBAF, the current program will be extended to include the η and η ′ mesons.Spontano kršenje kiralne simetrije i kiralne anomalije u niskoenergijskoj QCD očituju se najnedvosmislenije za lake pseudoskalarne mezone. Dakle, razumijevanje elektromagnetskih svojstava tih mezona je ključno za provjeru QCD u sektoru sužanjstva. Proučavanje širina dvofotonskog raspada π 0 , η i η ′ ima temeljnu važnost za određivanje efekata miješanja među tim mezonima i za dobivanje omjera masa lakih kvarkova. Suradnja PrimEx ima opsežan program za precizna mjerenja širina raspada π 0 → γγ putem Primakoffovog efekta. Planirano povećanje energije CEBAF na 11 GeV omogućit će proširenje na η i η ′ mezone

Mjerenje radijativne širine lakih pseudoskalarnih mezona na 11 GeV promakoffovim efektom

The spontaneous breaking of chiral symmetry and the chiral anomalies in low-energy QCD are manifested in their most unambiguous form in the light pseudoscalar mesons sector. Understanding the electromagnetic properties of these mesons are, therefore, crucial for probing QCD at the confinement scale. The study of two-photon decay widths of the π 0 , η, and η ′ are of fundamental importance in determining mixing effects among the mesons and in obtaining the light-quark mass ratios. The PrimEx collaboration at Jefferson Lab has a comprehensive program to perform a high precision measurement of the π 0 → γγ decay width via the Primakoff effect. With the planned 11 GeV upgrade of CEBAF, the current program will be extended to include the η and η ′ mesons.Spontano kršenje kiralne simetrije i kiralne anomalije u niskoenergijskoj QCD očituju se najnedvosmislenije za lake pseudoskalarne mezone. Dakle, razumijevanje elektromagnetskih svojstava tih mezona je ključno za provjeru QCD u sektoru sužanjstva. Proučavanje širina dvofotonskog raspada π 0 , η i η ′ ima temeljnu važnost za određivanje efekata miješanja među tim mezonima i za dobivanje omjera masa lakih kvarkova. Suradnja PrimEx ima opsežan program za precizna mjerenja širina raspada π 0 → γγ putem Primakoffovog efekta. Planirano povećanje energije CEBAF na 11 GeV omogućit će proširenje na η i η ′ mezone

Study of Volcanic Sediments by Microbeam-PIXE Technique

Single mineral grains in a suite of Cretaceous (85–90 Ma) volcanic sedimentary rocks were analyzed using the microbeam-PIXE technique to understand fundamental geological processes responsible for micro-scale variation in elemental composition across mineral zones, twinning, cleavage planes, fractures and grain boundaries. Distributions of major and trace elements show distinct geochemical features indicative of a specific geological setting and a subsequent diagenetic process in these volcanic sediments. Examples of mineral zoning, microstructures of variable chemistry and post-depositional fluid flow are discussed using the data on feldspar group of minerals

STR-928: SHEAR RESISTANCE OF COMPOSITE BEAMS WITHOUT SHEAR REINFORCEMENT

This paper presents the shear behaviour of composite beams made of combinations of high performance concretes (HPCs) such as self-consolidating concrete (SCC) and ductile Engineered Cementitious Composite (ECC). The variables in this experimental and Code based study was shear span to depth ratio, concrete types, longitudinal reinforcement and depth ratio (of ECC and SCC layer). The performance of ECC-SCC composite beams was compared with full depth normal SCC beams based on load-deformation response, stress-strain development, shear strength, failure mode, energy absorption capacity and aggregate-dowel action. The performance of American code in predicting shear strength of SCC beams including ECC-SCC composite beams was studied based on experimental results

STR-927: SHEAR RESISTANCE OF LIGHTWEIGHT SELF-CONSOLIDATING CONCRETE BEAMS

This paper presents the shear behavior of lightweight self-consolidating concrete (LWSCC) beams without shear reinforcement compared to those made with normal weight self-consolidating concrete (SCC). The variables in this experimental and Code based study was shear span to depth ratio, concrete types and longitudinal reinforcement. The performance of LWSCC was compared with normal SCC beams based on load-deformation response, stress-strain development, and shear strength and failure modes. LWSCC beams showed lower post-cracking shear resistance and the shear strength of LWSCC/SCC beams increased with the decrease of shear span to depth ratio. LWSCC beams showed higher number of cracks and wider crack width at failure than their SCC counterparts. American, Canadian and British Codes were conservative in predicting shear strength of LWSCC beams

STR-920: STRUCTURAL BEHAVIOUR OF REINFORCED HIGH PERFORMANCE CONCRETE COLUMNS SUBJECTED TO MONOTONIC AXIAL LOADING

This paper presents the results of experimental and analytical investigations on the structural performance of high performance reinforced concrete (HPC) columns subjected to monotonic axial loading. Reinforced columns made of self-consolidating concrete (SCC), engineered cementitious composite (ECC) and ultra-high performance concrete (UHPC) were tested to failure under axial loading. The test variables included concrete strength and length/slenderness of columns (classified as short and long columns). The UHPC and ECC columns demonstrated excellent ductility and higher energy absorbing capacity compared to their SCC counterparts. UHPC columns also illustrated higher ultimate load capacity compared to both ECC and SCC columns. The efficiency of UHPC and ECC columns was also judged based on strength and ductility ratio compared to their SCC counterparts. Existing models and other Code based equations were used to predict the axial load capacity as a part of analytical investigation. The predictions suggested the need for the modification of existing models/Code based equations for UHPC and ECC columns