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Showing result 1 - 5 of 25 essays matching the above criteria.

1. 1. Finding new members of the VelHel-4 stream

   University essay from KTH/Skolan för teknikvetenskap (SCI)

   Author : Lucas Johansson; [2023]
   Keywords : Galactic Archaeology; Milky Way; Stellar Streams; Streams; Stellar Halo; Stars; Globular Cluster; Astronomy; Astrophysics; Gaia; Chemical Abundance; Spectroscopy;

   Abstract : According to the paradigm of lambda-CDM cosmology, the stellar halo ofour Galaxy has been built-up over time through the accretion of other galaxiesand star clusters. The remnants of some of these are still observable today asstellar streams, but are typically very faint and difficult to resolve amidst the farmore numerous foreground Milky Way stars. READ MORE

3. 2. Determining backgrounds with misidentified leptons in the ATLAS Higgs boson analysis

   University essay from KTH/Fysik

   Author : Leo Qiyuan Hu; [2023]
   Keywords : Particle Physics; ATLAS detector; Fake Factor method; Higgs boson; lepton misreconstruction; misidentified events; Partikelfysik; ATLAS detektorn; Fake Factor-metoden; Higgs boson; lepton felrekonstruktion; felidentifierade händelser;

   Abstract : This thesis presents an analysis of misidentified leptons in the Higgs boson decaychannel H → W W ∗ → lνlν. Misidentified leptons, resulting from jets misidentifiedas leptons, mimic the signal of a Higgs boson decay, resulting in a backgroundcontribution to the signal. READ MORE

4. 3. Investigating a possible dearth of stars with zero angular momentum in the solar neighbourhood.

   University essay from Lunds universitet/Astronomi - Genomgår omorganisation; Lunds universitet/Fysiska institutionen

   Author : Aayush Desai; [2023]
   Keywords : Galaxy: disk; Galaxy: fundamental parameters; Galaxy: kinematics and dynamics; Galaxy: nucleus; solar neighborhood; stars: kinematics and dynamics; Physics and Astronomy;

   Abstract : Background. Carlberg & Innanen (1987) first proposed the idea of measuring the solar re- flex velocity (the velocity of the Sun around the galactic centre), Vg,⊙, using the momenta of the stars in the solar neighbourhood. The proposal was a consequence of the work of L. READ MORE

5. 4. Non-perturbative models of diffractive hadronic collisions

   University essay from Lunds universitet/Teoretisk partikelfysik - Geonomgår omorganisation

   Author : Edgars Karnickis; [2022]
   Keywords : diffractive process; proton-proton collision; elastic; parton; PDF; saturation; Physics and Astronomy;

   Abstract : In this thesis, a new model for diffractive proton-proton collisions is presented. Interpreting protons as systems of many partons, we treat diffraction in terms of elastic interactions between the partons of the colliding protons. READ MORE

6. 5. Theories with higher-order time derivatives and the Ostrogradsky ghost

   University essay from Stockholms universitet/Fysikum

   Author : Eleonora Svanberg; [2022]
   Keywords : Ostrogradsky ghost; higher-order time derivatives theories; Lagrangian mechanics; mathematical physics; Hamiltonian formalism;

   Abstract : Newton's second law, Schrödinger's equation and Maxwell's equations are all theories composed of at most second-time derivatives. Indeed, it is not often we need to take the time derivative of the acceleration. READ MORE