Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Graduation project 2018 Group G15

This paper aims to examine the uses and limitations of value added tax in Egypt The research uses the primary approach in collecting the required data through designing and distributing a questionnaire For a sample of tax officers in the Egyptian tax authority and tax experts from different public accounting firms in addition the research uses the quantitative approach in analyzing the collected data through applying SPSS software. The results of this study indicates that the agreement of all macro and micro uses of value added tax and the disagreement of macro and micro limitations of vat, so most of people saw that the benefits of value added tax in Egypt that vat is proportional tax and increases the level of export, minimizes tax evasion, improve the level of society fairness and stable source of government revenue in macro levelPresented To: DR: Tarek el-shazl