The present theoretical framework to describe the universe in particle level, the Standard Model describes only 4% of the matter-energy budget of the universe. There are many theories which attempt to describe the universe beyond the scope of the Standard Model. This dissertation describes a search for supersymmetry, a beyond Standard Model theory, using data collected by the Compact Muon Solenoid detector with integrated luminosity of 2.3 fb⁻¹ at a center of mass energy of 13 TeV during 2015. The data were produced in proton-proton collisions at the Large Hadron Collider near Geneva, Switzerland. This search was performed with events having two photons and missing transverse energy in the final state. This final state was motivated by general gauge mediated supersymmetry breaking, one of the theories on how breaking of supersymmetry can be mediated. No significant excess over the expected background was observed. The result was interpreted with simplified model scans and 95% upper limit on production cross sections are provided. / A Dissertation submitted to the Department of Physics in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Summer Semester 2016. / June 29, 2016. / 13 TeV, CMS, Missing Transverse Energy, Photon, Supersymmetry / Includes bibliographical references. / Andrew Askew, Professor Directing Dissertation; Gary Tyson, University Representative; Todd Adams, Committee Member; Laura Reina, Committee Member; Jorge Piekarewicz, Committee Member.

Hadronic form factors for semileptonic decay of the Λ[subscript c] are calculated in a nonrelativistic quark model. The full quark model wave functions are employed to numerically calculate the form factors to all orders in (1/m[subscript c], 1/m[subscript s]). The form factors satisfy relationships expected from the heavy quark effective theory (HQET) form factors. No other semileptonic decays of Λ[subscript c] has been reported other than the decay to the ground state Λ that implies f = B(Λ[subscript c]⁺ → Λl⁺ν[subscript l])/B(Λ[subscript c]⁺ → X[subscript s]l⁺ν[subscript l]) = 1. In this work, the differential decay rates and branching fractions are calculated for transitions to the ground state and a number of excited states of Λ. The branching fraction of the semileptonic decay width to the total width of Λ[subscript c] has been calculated and compared with other theoretical estimates and experimental results. The branching fractions for Λ[subscript c] → Λ*l⁺ν[subscript l] → Σπl⁺ν[subscript l] and Λ[subscript c] → Λ*l⁺ν[subscript l] → NǨl⁺ν[subscript l] are also calculated. Apart from decays to the ground state Λ(1115), it is found that decays through the Λ(1405) provide a significant portion of the branching fraction Λ[subscript c] → X[subscript s]lν[subscript l]. There are various conjectures on the structure of the Λ(1405) while we treated it as a three quark state. A new estimate for f = B(Λ[subscript c]⁺ → Λl⁺ν[subscript l] is obtained. / A Dissertation submitted to the Department of Physics in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Spring Semester 2017. / March 20, 2017. / Includes bibliographical references. / Winston Roberts, Professor Directing Dissertation; Kenneth Goldsby, University Representative; Alexander Volya, Committee Member; Volker Crede, Committee Member; Joseph Owens, Committee Member.

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