Dark Matter-Neutrino Interaction in Light of Collider and Neutrino Telescope Data

We study the DM-neutrino interaction in the framework of simplified model. The phenomenology of such an interaction are derived. We also investigate the bound on DM-neutrino interaction from the LHC and neutrino telescopes. We find that for the case of a scalar dark matter, the LHC gives a stronger bound on dark matter annihilation cross-section than the neutrino telescopes. However, for the fermionic dark matter case the neutrino telescopes bounds are more stringent for dark matter mass, $\gtrsim 200$ MeV. In the case of lower DM mass, the neutrino telescopes provide better bounds for a light mediator, while the collider bounds are better for a heavy mediator. Possible UV completions of the simplified model are briefly discussed.Comment: 23 pages, 12 figures. Add discussion on DM-neutrino interaction. References updated. Match JHEP versio

Probing Lepton Flavor Violation at the 13 TeV LHC

We investigate the bounds on tau-mu lepton flavor violation (LFV). Our main focus is on the collider constrains on tau-mu LFV. We use the Type-III Two-Higgs-Doublet-Model (2HDM) as a set up for our study. While the LFV branching fraction of the 125 GeV is well constrained by current LHC searches, the heavier neutral states could have a large branching fraction to tau and muon. We estimate the LHC reach for the 13 TeV center of mass energy with 300 $\text{fb}^{-1}$ luminosity for a neutral boson decaying into a tau and a muon. We identify parts of the LFV parameter space where the searches for heavy scalar and pseudoscalar decaying into a tau and a muon are more sensitive than the similar search for the 125 GeV boson.Comment: 29 + 3 pages, 23 figures. Version 2 expanded discussion of low energy constraints and added more references. Matched the JHEP versio

Composition Structure of Interplanetary Coronal Mass Ejections From Multispacecraft Observations, Modeling, and Comparison with Numerical Simulations

We present an analysis of the ionic composition of iron for two interplanetary coronal mass ejections observed in May 21-23 2007 by the ACE and STEREO spacecraft in the context of the magnetic structure of the ejecta flux rope, sheath region, and surrounding solar wind flow. This analysis is made possible due to recent advances in multispacecraft data interpolation, reconstruction, and visualization as well as results from recent modeling of ionic charge states in MHD simulations of magnetic breakout and flux cancellation CME initiation. We use these advances to interpret specific features of the ICME plasma composition resulting from the magnetic topology and evolution of the CME. We find that in both the data and our MHD simulations, the flux ropes centers are relatively cool, while charge state enhancements surround and trail the flux ropes. The magnetic orientation of the ICMEs are suggestive of magnetic breakout-like reconnection during the eruption process, which could explain the spatial location of the observed iron enhancements just outside the traditional flux rope magnetic signatures and between the two ICMEs. Detailed comparisons between the simulations and data were more complicated, but a sharp increase in high iron charge states in the ACE and STEREO-A data during the second flux rope corresponds well to similar features in the flux cancellation results. We discuss the prospects of this integrated in-situ data analysis and modeling approach to advancing our understanding of the unified CME-to-ICME evolution.Comment: Accepted for submission to The Astrophysical Journa

The Temperature-Dependent Nature of Coronal Dimmings

The opening-up of the magnetic field during solar eruptive events is often accompanied by a dimming of the local coronal emission. From observations of filament eruptions recorded with the Extreme-Ultraviolet Imager on STEREO during 2008-2009, it is evident that these dimmings are much more pronounced in 19.5 nm than in the lower-temperature line 17.1 nm, as viewed either on the disk or above the limb. We conclude that most of the cooler coronal plasma is not ejected but remains gravitationally bound when the loops open up. This result is consistent with Doppler measurements by Imada and coworkers, who found that the upflow speeds in a transient coronal hole increased dramatically above a temperature of 1 MK; it is also consistent with the quasistatic behavior of polar plumes, as compared with the hotter interplume regions that are the main source of the fast solar wind. When the open flux reconnects and closes down again, the trapped plasma is initially heated to such high temperatures that it is no longer visible at Fe IX 17.1 nm. Correspondingly, 17.1 nm images show a dark ribbon or ``heat wave'' propagating away from the polarity inversion line and coinciding with the brightened Fe XV 28.4 nm and Fe XII 19.5 nm post-eruptive loops and their footpoint areas. Such dark ribbons provide a clear example of dimmings that are not caused by a density depletion. The propagation of the ``heat wave'' is driven by the closing-down, not the opening-up, of flux and can be observed both off-limb and on-disk.Comment: 5 figures, movies are available online on the ApJL websit

The Dark Penguin Shines Light at Colliders

Collider experiments are one of the most promising ways to constrain Dark Matter (DM) interactions. For several types of DM-Standard Model couplings, a meaningful interpretation of the results requires to go beyond effective field theory, considering simplified models with light mediators. This is especially important in the case of loop-mediated interactions. In this paper we perform the first simplified model study of the magnetic dipole interacting DM, by including the one-loop momentum-dependent form factors that mediate the coupling -- given by the Dark Penguin -- in collider processes. We compute bounds from the monojet, monophoton, and diphoton searches at the $8$ and $14$ TeV LHC, and compare the results to those of direct and indirect detection experiments. Future searches at the $100$ TeV hadron collider and at the ILC are also addressed. We find that the optimal search strategy requires loose cuts on the missing transverse energy, to capture the enhancement of the form factors near the threshold for on-shell production of the mediators. We consider both minimal models and models where an additional state beyond the DM is accessible. In the latter case, under the assumption of anarchic flavor structure in the dark sector, the LHC monophoton and diphoton searches will be able to set much stronger bounds than in the minimal scenario. A determination of the mass of the heavier dark fermion might be feasible using the $M_{T2}$ variable. In addition, if the Dark Penguin flavor structure is almost aligned with that of the DM mass, a displaced signal from the decay of the heavier dark fermion into the DM and photon can be observed. This allows us to set constraints on the mixings and couplings of the model from an existing search for non-pointing photons.Comment: 32 pages + appendices and references, 22 figure

Dorieus und Kleomenes I. : Überlegungen zu Hdt. 5,39-48

Dorieus von Sparta und seine gescheiterten Expeditionen nach Libyen und Sizilien haben aufgrund knapper Quellennachrichten in der Forschung nur wenig Beachtung gefunden. Der ausführlichste und, wie bereits Benediktus Niese anmerkte, eigentlich einzige antike Bericht findet sich im fünften Buch der Historien Herodots. Selbiger kommt im siebten Buch (158 u. 205) nochmals kurz auf Dorieus zu sprechen und erwähnt im neunten Buch (10) dessen Sohn Euryanax. Diodor und Pausanias bieten kurze Erwähnungen, die auf Herodot basierend lediglich knappe zusätzliche Informationen beinhalten und nur dank des Halikarnassiers zu kontextualisieren sind. Dorieus’ Versuch, sowohl in Libyen, als auch auf Sizilien spartanische Apoikien zu gründen, „hat sich die Forschung nie so recht erklären können.“ Dieser Beitrag wird der schmalen Quellenüberlieferung ebenfalls keine gänzliche Erklärung abgewinnen können. Aber es soll der Versuch unternommen werden, die beiden „Auswanderungsversuche“ mit der innenpolitischen Situation unter der Herrschaft des Kleomenes I., des älteren Halbbruders des Dorieus, in Verbindung zu setzen bzw. die Möglichkeit von Abhängigkeiten zu ergründen und dabei auf die herodoteische Gestaltung der Dorieus-Episode einzugehen. Dorieus wird in Teilen der Forschung als Oikist bezeichnet, der in Sparta selbst keine Aussicht auf politischen Aufstieg gehabt und deshalb aus persönlicher Motivation heraus auswärtige Betätigungsfelder gesucht habe. Worauf gründet sich jedoch die für Sparta, ganz besonders für einen spartanischen Königssohn, untypische Motivation, in die Ferne zu ziehen – sogar wiederholt ein solches Unterfangen zu wagen