Physics

Since late July, the cosmic ray community has scrambled to explain the positron/electron ratio spectrum from the PAMELA satellite at 1 E 50 GeV. Combining this with previous data on the electron cosmic ray spectrum, we now have evidence for a...

Since late July, the cosmic ray community has scrambled to explain the positron/electron ratio spectrum from the PAMELA satellite at 1 E 50 GeV. Combining this with previous data on the electron cosmic ray spectrum, we now have evidence for a...

We give a physical explanation of the Kontsevich-Soibelman wall-crossing formula for the BPS spectrum in Seiberg-Witten theories. In the process we give an exact description of the BPS instanton corrections to the hyperkahler metric of the moduli...