NPAC (Nuclear/Particle/Astro/Cosmo) Forums

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Organized by: Prof. Lu Lu

Events During the Week of August 20th through August 27th, 2017

Monday, August 21st, 2017

No events scheduled

Tuesday, August 22nd, 2017

No events scheduled

Wednesday, August 23rd, 2017

No events scheduled

Thursday, August 24th, 2017

No events scheduled

Friday, August 25th, 2017

Cosmic rays, anti-helium, and an old navy spotlight
Time: 11:00 am
Place: 5280 Chamberlin Hall
Speaker: Kfir Blum, Weizmann Institute of Sciences
Abstract: Cosmic-ray anti-deuterium and anti-helium have long been suggested as probes of dark matter, as their secondary astrophysical production was thought extremely scarce. But how does one actually predict the secondary flux? Anti-nuclei are dominantly produced in pp collisions, where laboratory cross section data is lacking. We make a new attempt at tackling this problem by appealing to a scaling law of nuclear coalescence with the physical volume of the hadronic emission region. The same volume is probed by Hanbury Brown-Twiss (HBT) two-particle correlations. We demonstrate the consistency of the scaling law with systems ranging from central and off-axis AA collisions to pA collisions, spanning 3 orders of magnitude in coalescence yield. Extending the volume scaling to the pp system, HBT data allows us to make a new estimate of coalescence, that we test against preliminary ALICE pp data. For anti-helium the resulting cross section is 1-2 orders of magnitude higher than earlier estimates. The astrophysical secondary flux of anti-helium could be within reach of a five-year exposure of AMS02.
Host: Albrecht Karle
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