Searches For Dijet Resonances

This book addresses one of the most intriguing mysteries of our universe: the nature of dark matter. The results presented here mark a significant and substantial contribution to the search for new physics, in particular for new particles that couple to dark matter. The first analysis presented is a search for heavy new particles that decay into pairs of hadronic jets (dijets). This pioneering analysis explores unprecedented dijet invariant masses, reaching nearly 7 TeV, and sets constraints on several important new physics models. The two subsequent analyses focus on the difficult low dijet mass region, down to 200 GeV, and employ a novel technique to efficiently gather low-mass dijet events. The results of these analyses transcend the long-standing constraints on dark matter mediator particles set by several existing experiments.

This book introduces the reader to the field of jet substructure, starting from the basic considerations for capturing decays of boosted particles in individual jets, to explaining state-of-the-art techniques. Jet substructure methods have become ubiquitous in data analyses at the LHC, with diverse applications stemming from the abundance of jets in proton-proton collisions, the presence of pileup and multiple interactions, and the need to reconstruct and identify decays of highly-Lorentz boosted particles. The last decade has seen a vast increase in our knowledge of all aspects of the field, with a proliferation of new jet substructure algorithms, calculations and measurements which are presented in this book. Recent developments and algorithms are described and put into the larger experimental context. Their usefulness and application are shown in many demonstrative examples and the phenomenological and experimental effects influencing their performance are discussed. A comprehensive overview is given of measurements and searches for new phenomena performed by the ATLAS and CMS Collaborations. This book shows the impressive versatility of jet substructure methods at the LHC.

This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.

This thesis reports on the search for dark matter in data taken with the ATLAS detector at CERN’s Large Hadron Collider (LHC). The identification of dark matter and the determination of its properties are among the highest priorities in elementary particle physics and cosmology. The most likely candidate, a weakly interacting massive particle, could be produced in the high energy proton-proton collisions at the LHC. The analysis presented here is unique in looking for dark matter produced together with a Higgs boson that decays into its dominant decay mode, a pair of b quarks. If dark matter were seen in this mode, we would learn directly about the production mechanism because of the presence of the Higgs boson. This thesis develops the search technique and presents the most stringent production limit to date.

This volume contains contributions to the workshop, which was largely focused on the strong coupling gauge theories in search for theories beyond the standard model, particularly, the LHC experiments and lattice studies of conformal fixed point. The main topics include walking technicolor and the role of conformality in view of the 125 GeV Higgs as a light composite Higgs (technidilaton, and other composite Higgs, etc.). Nonperturbative studies like lattice simulations and stringy/holographic approaches are extensively discussed in close relation to the phenomenological studies. After the discovery of 125 GeV Higgs at LHC, the central issue of particle physics is now to reveal the dynamical origin of the Higgs itself. One of the possibilities would be the composite Higgs based on the strong coupling gauge theory in the TeV region, such as the technidilaton predicted in walking technicolor with infrared conformality. The volume contains, among others, many of the latest important reports on walking technicolor and related subjects in the general context of conformality, in a way of direct relevance to the LHC phenomenology as well as the lattice studies. It is very timely to study full theoretical implications in the exciting era when the LHC is vigorously working. This volume is of great importance for that purpose. Speakers of 40 talks (plus posters) include K-I Aoki, Y Aoki, K Bamba, E Bennett, R S Chivukula, H Georgi, A Hasenfratz, D-K Hong, K Itoh, D Elander, G Fleming, H Fukano, Y Iwasaki, M Jarvinen, D Kadoh, S Kim, R Kitano, K-I Kondo, J Kuti, D Lin, N Maru, H Matsufuru, S Matsuzaki, K-I Nagai, C Nonaka, H Ohki, E Pallante, M Rho, E Rinaldi, F Sannino, D Schaich, A Shibata, R E Shrock, E H Simmons, K Tuominen, C H Wong, N Yamada, M J S Yang, and K Yamawaki.

This volume contains contributions which are largely focused on strong coupling gauge theories and the search of theories beyond the standard model, as well as new aspects in hot and dense QCD — particularly in view of the LHC experiments and the lattice studies of conformal fixed point. It contains, among others, many of the latest and important reports on walking technicolor and related subjects in the general context of conformality, discussions of phenomenological implications with the LHC, as well as the theoretical ones through lattice studies. Nonperturbative studies like lattice simulations and stringy/holographic approaches are extensively elaborated in close relation to phenomenological studies. Also, heavy ion experiments at LHC are discussed in such nonperturbative approaches. Contents:Conformal Window and Correlation Functions in Lattice Conformal QCD (Y Iwasaki)Phase Structure of Many Flavor Lattice QCD at Finite Temperature (Norikazu Yamada and Shinji Ejiri)Conformal Dynamics and Thermal/Bulk Phase Transition in Lattice Gauge Theory with Many Fermion Species (Kohtaroh Miura, Maria Paola Lombardo, Elisabetta Pallante, Tiago Nunes da Silva and Albert Deuzeman)Latest ATLAS Results on Higgs and BSM physics (Osamu Jinnouchi)Holographic Technidilaton and LHC Searches (Maurizio Piai)Higgs Boson Mass and the Scale of New Physics (M Shaposhnikov)Metastable D-term Dynamical SUSY Breaking (Nobuhito Maru)Dynamical Model Based on Hydrodynamics for Relativistic Heavy-Ion Collisions (Chiho Nonaka, Yukinao Akamatsu, Shu-ichiro Inutsuka and Makoto Takamoto)Dilatons in Dense Baryonic Matter (Hyun Kyu Lee and Mannque Rho)Non-Abelian Strings in Supersymmetric Yang–Mills and Beyond (M Shifman)Partial Mass-Degeneracy and Spontaneous CP Violation in the Lepton Sector (Hiroyuki Ishida)Localization and ABJ Wilson Loop Calculation (Keita Nii, Shinji Hirano and Masaki Shigemori)QCD Corrections to Electric Dipole Moment from Dimension-six Four-Quark Operators (Koji Tsumura)Analysis of the Scalar Tetraquarks on the Lattice (Masayuki Wakayama and Chiho Nonaka)and other papers Readership: Graduate students, researchers and professionals in the fields of particle theory, particle experiment and astrophysics/cosmology. Keywords:Strong Coupling;LHC;Composite Higgs;Walking Technicolor;Lattice;Conformal;Scale Invariance;Fixed Point;Nonperturbative Solution;Large Nf QCD;Dilaton;Hot and Dense QCDKey Features:Maintains a unique tradition of compiling a series of the Nagoya SCGT workshops since 1988 on phenomenological studies and the theoretical ones, particularly the lattice studies on the strong coupling gauge theories for the electroweak symmetry breaking42 talks (plus posters) including those by R S Chivukula, L Del Debbio, B Grinstein, A Hasenfratz, C T Hill, Y Iwasaki, M Karliner, K Konishi, J Kuti, V A Miransky, B Mueller, F Sannino, M Shaposhnikov, M Shifman, R E Shrock, E H Simmons, amongst others

This book presents the proceedings of The International Workshop on Frontiers in High Energy Physics (FHEP 2019), held in Hyderabad, India. It highlights recent, exciting experimental findings from LHC, KEK, LIGO and several other facilities, and discusses new ideas for the unified treatment of cosmology and particle physics and in the light of new observations, which could pave the way for a better understanding of the universe we live in. As such, the book provides a platform to foster collaboration in order to provide insights into this important field of physics.

This volume of the CRM Conference Series is based on a carefully refereed selection of contributions presented at the "11th International Symposium on Quantum Theory and Symmetries", held in Montreal, Canada from July 1-5, 2019. The main objective of the meeting was to share and make accessible new research and recent results in several branches of Theoretical and Mathematical Physics, including Algebraic Methods, Condensed Matter Physics, Cosmology and Gravitation, Integrability, Non-perturbative Quantum Field Theory, Particle Physics, Quantum Computing and Quantum Information Theory, and String/ADS-CFT. There was also a special session in honour of Decio Levi. The volume is divided into sections corresponding to the sessions held during the symposium, allowing the reader to appreciate both the homogeneity and the diversity of mathematical tools that have been applied in these subject areas. Several of the plenary speakers, who are internationally recognized experts in their fields, have contributed reviews of the main topics to complement the original contributions. .