117935318
CP‐Violating Sources for Electroweak Baryogenesis
In this talk I derive the CP‐violating sources for the squark number density in the MSSM generated by interactions with the spacetime‐varying Higgs vev during a first‐order electroweak phase transition.
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.
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.
119269079
Double non-global logarithms in-n-out of jets
A bstractWe derive the leading non-global logarithms (NGLs) of ratios of jet masses m1,2 and a jet energy veto Λ due to soft gluons splitting into regions in and out of jets. Such NGLs appear in any exclusive jet cross section with multiple jet measurements or with a veto imposed on additional jets. Here, we consider back-to-back jets of radius R produced in e+e− collisions, found with a cone or recombination algorithm. The leading NGLs are of the form $\alpha_{\text{s}}^2{\text{l}}{{\text{n}}^2}(\Lambda /{m_{{1},{2}}})$ or $\alpha_{\text{s}}^2{\text{l}}{{\text{n}}^2}({m_1}/{m_2})$. Their coefficients depend both on the algorithm and on R. We consider cone, kT, anti-kT, and Cambridge-Aachen algorithms. In addition to determining the full algorithmic and R dependence of the leading NGLs, we derive new relations among their coefficients. We also derive to all orders in αs a factorized form for the soft function S(kL, kR, Λ) in the cross section σ(m1, m2, Λ) in which dependence on each of the global logs of μ/kL, μ/kR and μ/Λ determined by the renormalization group are separated from one another and from the non-global logs. The same kind of soft function, its associated non-global structure, and the algorithmic dependence we derive here will also arise in exclusive jet cross sections at hadron colliders, and must be understood and brought under control to achieve precise theoretical predictions.
119839635
Baryogenesis and EDMs: Constraining CP Violation Beyond the Standard Model
New sources of CPviolation beyond the Standard Model may help the scenario of electroweak baryogenesis (EWB) to account for the baryon asymmetry of the universe, and may be detectable in searches for permanent electric dipole moments of fundamental particles. In this talk, I focus on the calculation of the sources and relaxation rates in the transport equations for particle densities in the closed time path formalism of quantum field theory, suitable for the finite temperature and out-of-equilbrium conditions present at the electroweak phase transition. Applying the methods of closed time-path quantum field theory to derive transport equations relevant for EWB in the MSSM, we find regions of the parameter space where generation of the baryon asymmetry is resonantly enhanced, allowing successful baryogenesis with CP-violating phases small enough to be consistent with experimental limits on electron and neutron EDMs
17888703
Resonant Flavor Oscillations in Electroweak Baryogenesis
Electroweak baryogenesis (EWBG) in extensions of the Standard Model will be tested quantitatively in upcoming nuclear and particle physics experiments, but only to the extent that theoretical computations are robust. Currently there exist orders-of-magnitude discrepancies between treatments of charge transport dynamics during EWBG performed by different groups, each relying on different sets of approximations. In this work, we introduce a consistent power counting scheme (in ratios of length scales) for treating systematically the dynamics of EWBG: CP-asymmetric flavor oscillations, collisions, and diffusion. Within the context of a simplified model of EWBG, we derive the relevant Boltzmann equations using non-equilibrium field theory, and solve them exactly without ansatz for the functional form of the density matrices. We demonstrate the existence of a resonant enhancement in charge production when the flavor oscillation length is comparable to the wall thickness. We compare our results with the existing treatment of EWBG by Konstandin, Prokopec, Schmidt, and Seco (KPSS) who previously identified the importance of flavor oscillations in EWBG. We conclude: (i) the power counting of KPSS breaks down in the resonant regime, and (ii) this leads to substantial underestimation of the charge generated in the unbroken phase, and potentially of the final baryon asymmetry.
119346419
Relics of cosmological quark-hadron phase transition
We propose that the amplified density fluctuations by the vanishing sound velocity effect during the cosmological quark-hadron phase transition lead to quark-gluon plasma lumps decoupled from the expansion of the universe, which may evolve to quark nuggets (QNs). Assuming power-law spectrum of density fluctuations, we investigate the parameter ranges for the QNs to play the role of baryonic dark matter and give inhomogeneities which could affect big-bang nucleosynthesis within the observational bounds of CMBR anisotropy. The QNs can give the strongest constraint ever found on the spectral index.
17425045
Tachyon Kinks
We study Born-Infeld type tachyonic effective action of unstable D2-brane with a runaway potential and find rich structure of static regular solitonic solutions. There exists only periodic array of tachyon kink-antikinks in pure tachyonic theory, however, in the presence of electromagnetic fields, solutions include periodic arrays, topological tachyon kinks, half kink, and bounces. Computed tension of each kink or single unit of the periodic array has T 1 = √ 2πT 2 or that with a multiplicative factor depending on electric field. When both electric and magnetic fields are turned on, fundamental string charge density has a confined component in addition to a constant piece. These evidences imply that the obtained codimension-1 objects are likely to be interpreted as D1-brane (and D1F1) or array of D1 ¯ D1 (and D1F1-¯ D1F1) as was the case without the electromagnetic fields. Generalization to unstable Dp-branes is straightforward.
1893865
Black-string solutions with arbitrary tension
We consider 1+4 dimensional black-string solutions which are invariant under translation along the fifth direction. The solutions are characterized by the two parameters, mass and tension, of the source. The Gregory-Laflamme solution is shown to be characterized by the tension whose magnitude is one half of the mass per unit length of the source. A general class of black-string solutions with arbitrary tension is presented and the spacetime properties of the solutions are discussed.
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.
15003439
CMBR anisotropy with primordial magnetic fields
Galactic magnetic fields are observed of order $\sim 10^{-6}G$, but their origin is not definitely known yet. In this paper we consider the primordial magnetic fields generated in the early universe and analyse their effects on the density perturbations and the CMBR anisotropy. We assume that the random magnetic fields have the power law spectrum and satisfy the force-free field condition. 
The peak heights of the CMBR anisotropy are shown to be shifted upward depending on the magnetic field strengths relative to the no-magnetic field case.