Collaboration Meeting, Erlangen, September 24, 2009

Collaboration Meeting, Erlangen, September 24, 2009

Update on Nuclearites

Gabriela Pavalas (the hard work), Vlad Popa (the “rest”…)

Short reminder from Marseille: What would be the imprint of a nuclearite in the available data? (How to obtain a flux limit?)

-Considering 2.2 µs time windows with a muon cluster trigger (at least 5 L1 hits).-A nuclearite would manifest through an excess of L0 hits! A linear cut was proposed.

(from one golden run, 5 strings data)

Selection cut

3

Background (data, MC muons) after cut: 0

Nuclearite mass (GeV)

3N Triggers after cut

Percentage of 3N triggers

Nuclearite events after cut

Percentage of events

3*1016 253 72.1% 196 72.8%

1*1017 24285 99.4% 1652 96.8%

Large part of the signal retained

29.260#127.01# LL triggered

Update: Trying to compute a limit from all 5 string golden runs, too many snapshots satisfied the single slice cut…A second cut introduced: multiple snapshot cut (multiple snapshots in a time window of 1 ms).

Nuclearite mass (GeV)

Triggered events

Percentage after linear cut

Percentage after multiple snapshot cut

3x1016 268 72.5% 16.3%

1x1017 1706 96.8% 89.1%

1x1018 319 98.7% 96.2%

But this is NOT the way to go. It could produce only flux upper limits that could worsen increasing the statistics!

Proposed acquisition scenario with discovery potential:

Data in a snapshot satisfies the first cut (L0 excess)

Record all raw data for about 20 ms (as for GRB’s, but much shorter)

Issue a warning to the group, that will download the data and analyze the event off-line. With 12 lines, events expected each few days.

Fast, robust and safe first-sight analysis tools needed. If the event survives, there will be “all the time” for detailed final analysis…

Fast “first sight” analysis method based on the “weight centers” of the distributions of the collected charge.

Is currently under development and tests using nuclearite MC simulations and the real GRB data.

(Thanks, Mieke!)

Just a very preliminary hint…

Data versus nuclearite simulation

GRB data

• GRB run 030324_61_0296683

• frame index 27649

• 104 ms

Nuclearite simulation

16103M GeV•

•V = 300 km/s• zenith angle 40 deg.• crossing time ~ 2ms

Explaining coordinates

GRB data Nuclearite simulation

z coord. of the charge weight center versus time


z coord. of the charge weight center versus time (2)


Charge versus time


Near the middle ofANTARES Closest approach to a

PMT (~ 1m)

2D x / y weight center coordinates


2D x / z weight center coordinates


GRB: <y> / <z> 1 frame = 10 ms

Nuclearite: <y> / <z> 1 frame = 200 µs

Getting more quantitative:

<z> - t correlation coefficients


<x> - <z> correlation coefficients


Conclusions and to do list

• Anomalous high L0 content muon triggers could be the “early warning” for the passage of a nuclearite and determine full data recording for ~ 20 ms

• Best criteria still to be decided

• More MC needed

• Mix the GRB data with the nuclearite MC (soon!!!)

• Go to 10 and 12 lines

• Start the real search for nuclearites!

Collaboration Meeting, Erlangen, September 24, 2009

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