The second session continues with more experimentally aligned talks.
11:00 am: Status of CMB observations: Planck and beyond, Martin Bucher
We all know what Planck is/was, of course. Long history: proposed back in 1992, accepted in 1996 but not launched till 2009. Second release earlier this year, with final results expected middle of next year. Main outstanding results from low-l polarisation data.
A slide that consisted of a table of data, too small to read, but most of the slide was empty. This seems emblematic of this talk. No, sorry, the fact that we had two slides like, one focused on and one flipped past too fast too even understand; that is this talk summarised.
11:45 am: Progress and Status of PandaX experiment in China Jinping Underground Lab, Xiangdong Ji
Another talk from Pheno! This time my old thoughts can be found here.
Start with comparison of Germanium vs liquid Xenon technology: both lead to exponential growth in sensitivity to DM. 2000-2010 saw Ge growth, but transition to LXe technology increased the increase in sensitivity!
One of the most bizarre claims I have ever seen: observation of Majorana neutrinos would provide evidence for supersymmetry! I've seen some desparate claims for SUSY; this isn't the worst, but it is the weirdest.
Experimental site: I remember this, based in a mountain to exploit a large effective shielding without having to use a mine.
PandaX-I published its result earlier this year. Small detector volume compared to e.g. LUX, but focused on low-mass region to probe the anomalies that have been found in the sub-10 GeV mass range. Uses the standard double-signal (light and charge/drift) feature of LXe experiments to distinguish nuclear and electron recoil. Also use self-shielding nature. This cuts background by factor of 100 alone.
Observed 7 events after all cuts, compared to 6.9 expected background. Excluded anomalies, but this had already been done by LUX and other experiments.
PandaX-II upgrade quadruples the detector volume. Construction began in 2014, currently calibrating and actual data to start in 2015. Currently the largest experiment of its kind in the world, till Xenon1T starts. Results expected by summer next year.
Now discussion on neutrinoless double-beta decay. This wasn't covered at Pheno. Constraints in some respects more stringent than a DM search: very low radioactivity background, and sub-percent level energy resolution. Two advantages over other proposals: tracking (can take pictures of events) and scalability. Easy to make ton-scale detectors with LXe technology. Further ton-scale experiments will be able to detect inverted hierarchy Majorana neutrinos. (Unfortunately, normal hierarchy decay rate can be arbitrarily low.) KamLAND is current experiment using LXe technology.
Can improve things using high-pressure Xenon gas. This can improve the energy resolution to the level needed. This is planned for PandaX-III. Another important development has been something to do with improved readout technology, which I didn't quite follow but is "10 times better" than what came before. Key part of imaging detector technology, look at tracks left in Xenon. Also need to use large water shielding (~10 m of ultra pure water).
Ultimate DM experiment, capable of going to the neutrino floor: 20-30 ton LXe or 50-100 ton LAr. Need a very good experimental site. Apparently no candidates in Europe! PandaX site? R&D going on; will current designs scale up, or will something new be needed? LZ experiment will give some information in that direction.
11:00 am: Status of CMB observations: Planck and beyond, Martin Bucher
We all know what Planck is/was, of course. Long history: proposed back in 1992, accepted in 1996 but not launched till 2009. Second release earlier this year, with final results expected middle of next year. Main outstanding results from low-l polarisation data.
A slide that consisted of a table of data, too small to read, but most of the slide was empty. This seems emblematic of this talk. No, sorry, the fact that we had two slides like, one focused on and one flipped past too fast too even understand; that is this talk summarised.
11:45 am: Progress and Status of PandaX experiment in China Jinping Underground Lab, Xiangdong Ji
Another talk from Pheno! This time my old thoughts can be found here.
Start with comparison of Germanium vs liquid Xenon technology: both lead to exponential growth in sensitivity to DM. 2000-2010 saw Ge growth, but transition to LXe technology increased the increase in sensitivity!
One of the most bizarre claims I have ever seen: observation of Majorana neutrinos would provide evidence for supersymmetry! I've seen some desparate claims for SUSY; this isn't the worst, but it is the weirdest.
Experimental site: I remember this, based in a mountain to exploit a large effective shielding without having to use a mine.
PandaX-I published its result earlier this year. Small detector volume compared to e.g. LUX, but focused on low-mass region to probe the anomalies that have been found in the sub-10 GeV mass range. Uses the standard double-signal (light and charge/drift) feature of LXe experiments to distinguish nuclear and electron recoil. Also use self-shielding nature. This cuts background by factor of 100 alone.
Observed 7 events after all cuts, compared to 6.9 expected background. Excluded anomalies, but this had already been done by LUX and other experiments.
PandaX-II upgrade quadruples the detector volume. Construction began in 2014, currently calibrating and actual data to start in 2015. Currently the largest experiment of its kind in the world, till Xenon1T starts. Results expected by summer next year.
Now discussion on neutrinoless double-beta decay. This wasn't covered at Pheno. Constraints in some respects more stringent than a DM search: very low radioactivity background, and sub-percent level energy resolution. Two advantages over other proposals: tracking (can take pictures of events) and scalability. Easy to make ton-scale detectors with LXe technology. Further ton-scale experiments will be able to detect inverted hierarchy Majorana neutrinos. (Unfortunately, normal hierarchy decay rate can be arbitrarily low.) KamLAND is current experiment using LXe technology.
Can improve things using high-pressure Xenon gas. This can improve the energy resolution to the level needed. This is planned for PandaX-III. Another important development has been something to do with improved readout technology, which I didn't quite follow but is "10 times better" than what came before. Key part of imaging detector technology, look at tracks left in Xenon. Also need to use large water shielding (~10 m of ultra pure water).
Ultimate DM experiment, capable of going to the neutrino floor: 20-30 ton LXe or 50-100 ton LAr. Need a very good experimental site. Apparently no candidates in Europe! PandaX site? R&D going on; will current designs scale up, or will something new be needed? LZ experiment will give some information in that direction.
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