188660712
Using 1-Jettiness to Measure 2 Jets in DIS 3 ways
26881716
Resonant relaxation in electroweak baryogenesis
We compute the leading, chiral charge-changing relaxation term in the quantum transport equations that govern electroweak baryogenesis using the closed time path formulation of nonequilibrium quantum field theory. We show that the relaxation transport coefficients may be resonantly enhanced under appropriate conditions on electroweak model parameters and that such enhancements can mitigate the impact of similar enhancements in the CP-violating source terms. We also develop a power counting in the time and energy scales entering electroweak baryogenesis and include effects through second order in ratios epsilon of the small and large scales. We illustrate the implications of the resonantly enhanced [script O](epsilon 2) terms using the Minimal Supersymmetric Standard Model, focusing on the interplay between the requirements of baryogenesis and constraints obtained from collider studies, precision electroweak data, and electric dipole moment searches.
119187963
Jet shapes and jet algorithms in SCET
Jet shapes are weighted sums over the four-momenta of the constituents of a jet and reveal details of its internal structure, potentially allowing discrimination of its partonic origin. In this work we make predictions for quark and gluon jet shape distributions in N-jet final states in e+e− collisions, defined with a cone or recombination algorithm, where we measure some jet shape observable on a subset of these jets. Using the framework of Soft-Collinear Effective Theory, we prove a factorization theorem for jet shape distributions and demonstrate the consistent renormalization-group running of the functions in the factorization theorem for any number of measured and unmeasured jets, any number of quark and gluon jets, and any angular size R of the jets, as long as R is much smaller than the angular separation between jets. We calculate the jet and soft functions for angularity jet shapes τα to one-loop order $ \left( {\mathcal{O}\left( {{\alpha_s}} \right)} \right) $ and resum a subset of the large logarithms of τα needed for next-to-leading logarithmic (NLL) accuracy for both cone and kT-type jets. We compare our predictions for the resummed τα distribution of a quark or a gluon jet produced in a 3-jet final state in e+e− annihilation to the output of a Monte Carlo event generator and find that the dependence on a and R is very similar.
118867883
Enhanced nonperturbative effects in Z decays to hadrons
We use soft collinear effective field theory (SCET) to study nonperturbative strong interaction effects in Z decays to hadronic final states that are enhanced in corners of phase space. These occur, for example, in the jet energy distribution for two jet events near E_J=M_Z/2, the thrust distribution near unity and the jet invariant mass distribution near zero. The extent to which such nonperturbative effects for different observables are related is discussed.
122534296
Peeking inside jets for clues of new physics
Observables probing jet structure and substructure help uncover clues about the energetic particles which originated them, such as ordinary light quarks and gluons or from decays of heavy particles in and beyond the Standard Model. This talk overviews such recently introduced methods.
119204877
Consistent Factorization of Jet Observables in Exclusive Multijet Cross-Sections
Abstract We demonstrate the consistency at the next-to-leading-logarithmic (NLL) level of a factorization theorem based on Soft-Collinear Effective Theory (SCET) for jet shapes in e + e − collisions. We consider measuring jet observables in exclusive multijet final states defined with cone and k T -type jet algorithms. Consistency of the factorization theorem requires that the renormalization group evolution of hard, jet, and soft functions is such that the physical cross section is independent of the factorization scale μ . The anomalous dimensions of the various factorized pieces, however, depend on the color representation of jets, choice of jet observable, the number of jets whose shapes are measured, and the jet algorithm, making it highly nontrivial to satisfy the consistency condition. We demonstrate the intricate cancellations between anomalous dimensions that occur at the NLL level, so that, up to power corrections that we identify, our factorization of the jet shape distributions is consistent for any number of quark and gluon jets, for any number of jets whose shapes are measured or unmeasured, for any angular size R of the jets, and for any of the algorithms we consider. Corrections to these results are suppressed by the SCET expansion parameter λ (set by the ratio of the typical momentum in a jet transverse to the jet axis to the total jet energy) and in the jet separation measure 1 / t 2 = tan 2 ( R / 2 ) / tan 2 ( ψ / 2 ) , where ψ is the angular separation between jets. Our results can be used to calculate a wide variety of jet observables in multijet final states to NLL accuracy.
119165559
Oscillating instanton solutions in curved space
We investigate oscillating instanton solutions of a self-gravitating scalar field between degenerate vacua. We show that there exist O(4)-symmetric oscillating solutions in a de Sitter background. The geometry of this solution is finite and preserves the $Z_{2}$ symmetry. The nontrivial solution corresponding to tunneling is possible only if the effect of gravity is taken into account. We present numerical solutions of this instanton, including the phase diagram of solutions in terms of the parameters of the present work and the variation of energy densities. Our solutions can be interpreted as solutions describing an instanton-induced domain wall or braneworld-like object rather than a kink-induced domain wall or braneworld. The oscillating instanton solutions have a thick wall and the solutions can be interpreted as a mechanism providing nucleation of the thick wall for topological inflation. We remark that $Z_{2}$ invariant solutions also exist in a flat and anti-de Sitter background, though the physical significance is not clear.
16403765
3-dimensional holographic trace anomaly from AdS/CFT correspondence
We explicitly obtain energy-momentum tensor at the asymptotic 3-dimensional region of Schwarzschild AdS$_4$ and Taub-NUT-(A)dS$_4$ using the so-called `counter-term subtraction method' in Fefferman-Graham coordinate. The energy momentum tensor is presented in a closed form for the AdS$_4$ and for the special case of Taub-NUT-dS and in an asymptotic series for other cases. The result suggests that in light of AdS/CFT correspondence, the 3-dimensional trace anomaly can be expressed in terms of the 3-dimensional volume and Ricci scalar.
117905421
The nucleation of false vacuum bubbles with compact geometries
We investigate and classify the possible types of false vacuum bubbles in Einstein gravity. The false vacuum bubbles can occur only if gravity is taken into account. We show that there exist solutions only with compact geometries. The analytic computations for the radius and nucleation rate of a vacuum bubble are evaluated using the thin-wall approximation. We discuss possible cosmological implications of our new solutions.
15692757
Magnetic alignment process: a new mechanism for extracting energy from rotating black holes
The magnetic alignment process is proposed as a complementary or companion process to the Blandford–Znajek mechanism for the rotational energy extraction from a Kerr black hole, to serve as a viable model for the central engine of quasars, AGN, and even GRB. In contrast to the environment assumed in the Blandford–Znajek mechanism, in which the rotating hole's spin axis and the asymptotic direction of the magnetic field are aligned, this new process operates when they are generally misaligned, which obviously is the more natural situation likely to happen. The time scales over which these two processes take place and the total radiated powers released at the horizon by them have been estimated and found to be nearly comparable. This may imply that in a random, non-axisymmetric configuration, the magnetic alignment process would operate first, during which some of the hole's rotational energy is released, and then upon completion of the alignment, the Blandford–Znajek mechanism may follow and the rest of the hole's rotational energy, if any left, would be further released.
55074643
Speculative Reading, Speculative Physics - the Ontology of the Large Hadron Collider
The objective is to illustrate the hermeneutics of reading against the highly image-dependent (rather than object-oriented) world of experimental particle physics. Reading becomes the medium for mediating between the real and the virtual when constructing physical knowledge. "Virtual" particles, produced through material inter-course between machine and nature, are productive for re- thinking the virtual/real entanglement. Reading enables a process of deconstructing and re-naturalizing microphysical trails, objects, and movements 'transformed' into machine code, post-detector. The process of reading is therefore the 'detection,' 'observation,' 'measurement,' 'abduction,' and 'interpretation' of coded information and knowledge; deciphered through data 'selected' for analysis, extrapolated as evidence for the confirmation/re-orientation of theoretical predictions, and included for the re-envisioning and revising of foundational explanations regarding the structure of modern physics. Reading as is explored here is about how reading as an act is inextricably linked with understanding one's perspective and the ideology one is immersed in, thus influencing how discovery is made and articulated through theory-construction.