Magic Monday Journal Club

May the 5th  2014

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Back to the root with a close look to recent particle physics activity after our desert trip..

And one wants to thank Michel Tytgat, our honored guest for his presence (first)

his sense of humor (second) and his nice presentation of the article

of Randall and Reece (fourth,because I do not like third).

Exotic Higgs decays in the golden channel

by A. Falkowski and R. Vega-Morales

The authors point out that  the exotic decays of the Higgs boson are cool, and, at the same time,  4-lepton final states of Higgs decays are cool too.  Thus, searching for exotic Higgs decays  in the 4-lepton channel is double cool.   For example, in the model with a light dark photon in the mas range 15-65 GeV, one can explore the new parameter space already in the next LHC run.

Dark Matter as a Trigger for Periodic Comet Impacts

  L. Randall and M. Reece

Dinosaurs or not, this paper decided to look at the possibilities that periodical catastrophes (I do not talk about the haircut of Adam) can occur on earth due to the passage of our solar system and the Oort belt in a dark matter disk. For the curious, we let them find the «confidence level» of the study (the p-value is in the paper, but one has to look for it). Their model of double disks of DM is also not so simple and one should have a look at their original paper to understand the subtleties of their work. The annotated version of the paper can be found around there.

3.55 keV photon lines from axion to photon conversion in the Milky Way and M31

by J. P. Conlon and F. V. Daya

One more paper about the 3.55 keV line, this time proposing a scenario where the dark matter does not decay directly to a photon, but to an axion which is then converted to a photon through the classical mechanism. The results depends of course of the galactic magnetic field. The main conclusion is that in the Milky Way,, the intensity of the magnetic field is too weak to be able to give any observable signal even in future dedicated experiments, whereas in M31 there is some hope to distinguish a directly decaying dark mater to a converted decaying dark mater looking more precisely on the map of the sky.   You can find an annotated version of the paper around here.


by H. Liu, P. Mertsch and S. Sarkar

The authors discuss the possibility that the so-called radio loops - the supernova explosion rings that emit radio waves  - may contribute to the cosmic microwave foreground.  If that is true, and if they contribute to the polarization signal as well, the presence of these objects may obscure the promordial B-mode interpretation of the BICEP signal.

Magnetic dark matter for the X-ray line at 3.55 keV

by H.M. Lee

Hyun Min.. My room mate who suffered my presence at DESY decided to write his part of the 3.55 keV cake too. So using the classical magnetic dipole interaction (can someone tell me why this interaction is so popular nowadays.. maybe to escape DD limits??) between two Dirac components (GeV scale), Hyun Min succeed in producing a right monochromatic line corresponding to the mass difference between the two Dirac state. It is quite similar to Exciting DM to my mind. Unfortunately, one of our magician noticed that there is a mistake in his paper as he took the lifetime corresponding to a keV DM whereas he should have taken the one correspinding to a GeV one. So please, rescale all his plot by a a factor of about 10^6-8 and all should be ok. The annotated version of the paper can be found around there.

Search for light massive gauge bosons as an explanation of the (g -2) anomaly at MAMI

by A1 collaboration

The A1 collaboration in MAMI updated the search for the dark photon with the mass in the 100 MeV ballpark.  They've excluded most of the parameter space where the simplest dark photon model  could explain the excess in the measured muon anomalous magnetic moment. They also propose quasar as an explanation of the PAMELA anomaly ;) 

Higgs portal vector dark matter for GeV scale  γ-ray excess from galactic center

by P. Ko, W. Park and Y. Tang

What can I say... Pyungwon and his team fits the GeV excess  «Hooperon» with a double Higgs portal and vectorial dark matter. Not surprisingly it works (almost) better than other version (that does not work because of some velocity dependance) thanks to new annihilation diagram into HH to obtain the correct relic abundance.  It is a serious work that will interest people interested in this kind of work.You can find an annotated version of the paper around here.