Difference between revisions of "Invisible decay"

From Lmdwiki
Jump to navigationJump to search
 
(28 intermediate revisions by the same user not shown)
Line 148: Line 148:
 
43634 14953 0.178628 -0.490327 1.02955 -0.228806 -0.0163596 0.204688 0.177539 0.268025 0.149043 225 2.9897
 
43634 14953 0.178628 -0.490327 1.02955 -0.228806 -0.0163596 0.204688 0.177539 0.268025 0.149043 225 2.9897
 
===Limited statistics with timing cut===
 
===Limited statistics with timing cut===
−
timing cut at ± 1 ns
+
timing cut at ± 1 ns
 +
 
 +
[[File:Compare mmp none expect.png]]
 +
 
 +
===All statistics===
 +
<table>
 +
<tr>
 +
<td>[[File:Comparison.png|thumb|400px|left|50% efficiency;Red: no decay detected; Blue: expected]]</td>
 +
<td>[[File:Ratio.png|thumb|400px|left|Difference between no decay detected and expected divided by all eta events of 50% efficiency]]</td>
 +
</tr>
 +
</table>
 +
==No Kin Fit==
 +
===Assign the Q value of each event===
 +
Assign Q value of each event according to the missing mass and missing mass of proton.
 +
<table>
 +
<tr>
 +
<td>[[File:MMPVSMM.png|thumb|400px|left|Missing mass of proton vs. missing mass]]</td>
 +
</tr>
 +
</table>
 +
 
 +
The events are separated into 9 groups according to the missing mass of proton between 0.9 and 1.8 GeV.
 +
 
 +
<table>
 +
<tr>
 +
<td>[[File:Mm_09_10.png|thumb|400px|left|Missing mass w/ missing mass of proton between 0.9 and 1.0 GeV]]</td>
 +
<td>[[File:Mm_10_11.png|thumb|400px|left|Missing mass w/ missing mass of proton between 1.0 and 1.1 GeV]]</td>
 +
<td>[[File:Mm_11_12.png|thumb|400px|left|Missing mass w/ missing mass of proton between 1.1 and 1.2 GeV]]</td>
 +
</tr>
 +
<tr>
 +
<td>[[File:Mm_12_13.png|thumb|400px|left|Missing mass w/ missing mass of proton between 1.2 and 1.3 GeV]]</td>
 +
<td>[[File:Mm_13_14.png|thumb|400px|left|Missing mass w/ missing mass of proton between 1.3 and 1.4 GeV]]</td>
 +
<td>[[File:Mm_14_15.png|thumb|400px|left|Missing mass w/ missing mass of proton between 1.4 and 1.5 GeV]]</td>
 +
</tr>
 +
<tr>
 +
<td>[[File:Mm_15_16.png|thumb|400px|left|Missing mass w/ missing mass of proton between 1.5 and 1.6 GeV]]</td>
 +
<td>[[File:Mm_16_17.png|thumb|400px|left|Missing mass w/ missing mass of proton between 1.6 and 1.7 GeV]]</td>
 +
<td>[[File:Mm_17_18.png|thumb|400px|left|Missing mass w/ missing mass of proton between 1.7 and 1.8 GeV]]</td>
 +
</tr>
 +
</table>
 +
The result after applying this value:
 +
 
 +
<table>
 +
<tr>
 +
<td>[[File:MMPVSMM weight.png|thumb|400px|left|Missing mass of proton vs. missing mass weighted]]</td>
 +
<td>[[File:MM weight.png|thumb|400px|left|missing mass weighted]]</td>
 +
 
 +
</tr>
 +
</table>
 +
 
 +
===Finer binning===
 +
 
 +
The events are separated into 75 groups according to the missing mass of proton between 0.9 and 1.8 GeV and 12 MeV per group.
 +
 
 +
The fitting results are in [https://www.jlab.org/Hall-B/secure/lmd/hlu/fit_mm_mmp_threeOnly.pdf fitting missing mass with p pi+ pi- detected only], and [https://www.jlab.org/Hall-B/secure/lmd/hlu/fit_mm_mmp_all.pdf fitting missing mass with all events of eta included]
 +
 
 +
<table>
 +
<tr>
 +
<td>
 +
 
 +
[https://www.jlab.org/Hall-B/secure/lmd/hlu/MMPVSMM_Weighted.png Missing mass of proton VS missing mass weighted]
 +
</td>
 +
<td>
 +
[https://www.jlab.org/Hall-B/secure/lmd/hlu/Missing_mass_proton_weighted.png missing mass or proton weighted]
 +
</td>
 +
</tr>
 +
</table>
 +
===Binning adjustment===
 +
The fitting itself looks good and the result from fitting is good too. The problem must come from the binning is too fine. Therefore, the number of binning changed from 75 to 30 for events with p pi+ pi- detected only.
 +
 
 +
[https://www.jlab.org/Hall-B/secure/lmd/hlu/fitting_mm_all_60.pdf fitting missing mass of eta with all events included (p pi+ pi- AT LEAST)]
 +
 
 +
[https://www.jlab.org/Hall-B/secure/lmd/hlu/fitting_mm_threeOnly_30.pdf fitting missing mass of eta with p pi+ pi- detected Only]
 +
 
 +
<table>
 +
<tr>
 +
<td>[[File:MM Weighted threeOnly 30.png|400px]]</td>
 +
<td>[[File:MMP ALL Weight.png|400px]]</td>
 +
</tr>
 +
</table>
 +
==Event-based Q value==
 +
<table>
 +
<tr>
 +
<td>
 +
[[File:mm.png]]
 +
</td>
 +
<td>
 +
[[File:mm_q.png]]
 +
</td>
 +
</tr>
 +
<tr>
 +
<td>
 +
[[File:mmp.png]]
 +
</td>
 +
<td>
 +
[[File:mmp_q.png]]
 +
</td>
 +
</tr>
 +
<tr>
 +
<td>
 +
[[File:comparison_q.png]]
 +
</td>
 +
</tr>
 +
</table>
 +
===Check the validity of Q value===
 +
<table>
 +
<tr>
 +
<td>
 +
[[File:Fitting mm.png|left|thumb|400px]]
 +
</td>
 +
<td>
 +
[[File:AveragedMMVSMMP.png|left|thumb|400px]]
 +
</td>
 +
</tr>
 +
<tr>
 +
<td>
 +
[[File:SideBandSubtractedMMVSMMP.png|left|thumb|400px]]
 +
</td>
 +
<td>
 +
[[File:SideBandSubtractedMMP.png|left|thumb|400px]]
 +
</td>
 +
</tr>
 +
 
 +
</table>
 +
===Accidental Photon===
 +
<table>
 +
<tr>
 +
<td>
 +
[[File:MM2VSMP PPipPim.png|left|thumb|400px]]
 +
</td>
 +
<td>
 +
[[File:MM2VSMP PPipPim Selection.png|left|thumb|400px]]
 +
</td>
 +
</tr>
 +
<tr>
 +
<td>
 +
[[File:NPhotonVSMP PPipPim Selection.png|left|thumb|400px]]
 +
</td>
 +
<td>
 +
[[File:NPhoton PPipPim Selection.png|left|thumb|400px]]
 +
</td>
 +
</tr>
 +
 
 +
</table>
  
 
==Reference==
 
==Reference==
 
arxiv:1209.2469
 
arxiv:1209.2469

Latest revision as of 16:55, 25 September 2015

Idea

B(inivisible)/B(normalization)={N(upper limit)/efficiency(invisible)}/{N(normalization)/efficiency(normalization)} * {1/(1-sigma)}

  • B(inivisible): branching ratio of the invisible decay
  • B(normalization): branching ratio of the reference channel
  • N(upper limit): upper limit of the yield of the invisible decay
  • N(normalization): yield of the reference channel
  • efficiency(invisible): acceptance of the invisible decay
  • efficiency(normalization): acceptance of the reference channel
  • sigma: systematic uncertainty

What applies here:

The channel we are using is : gamma p -> p eta_prime -> p pi+ pi－ （eta). The invisible decay of eta is eta -> xx. x is something like U boson, which could be dark photon or heavy photon.

B(normalization) is 1 when we obtain eta by requiring the missing mass.

efficiency(invisible)=efficiency(normalization) * efficiency (invisible decay of eta). efficiency(normalization) is the detection efficiency of p pi+ pi-. efficiency(invisible) is the product of efficiency(normalizaiton) and efficiency(invisible decay of eta). efficiency(invisible decay) is the detection efficiency of at least one photon from eta decay.

photon detection efficeincy

procedure

  • collection events of p, pi+, pi- and one or two photons
  • requiring the missing mass of p pi+ pi- to be pi0
  • requiring the missing mass of p to be eta or omega
  • events passing the above three conditions are called "all" events
  • two-photon events are called "good" events
  • the ratio of "good" events to "all" events is the detection efficiency of photon
  • the ratio is binned in energy, theta, and phi angle in lab frame

result

Error creating thumbnail: File missing
efficiency of photon in cosine theta vs. phi
Error creating thumbnail: File missing
efficency of photon in momentum vs. phi after selection cosine theta between 0.7 and 0.98

Eta acceptance

File:Eta efficiency.pdf

partial statistics

The following is from 2% of the data.

Mmp two photon subtracted.png

Mmp selected.png

Different efficiency

Error creating thumbnail: File missing
50% efficiency
Error creating thumbnail: File missing
50% efficiency
Error creating thumbnail: File missing
60% efficiency
Error creating thumbnail: File missing
60% efficiency
Error creating thumbnail: File missing
70% efficiency
Error creating thumbnail: File missing
70% efficiency

Compare expected and no-photon detected

Error creating thumbnail: File missing
Compare the events of no photon detected with expected from acceptance with acceptance larger than 0.5
Error creating thumbnail: File missing
Compare the events of no photon detected with expected from acceptance for all events
Error creating thumbnail: File missing
Ratio of the events of no photon detected to all events (red) and expected events to all events (blue)
Error creating thumbnail: File missing
Compare the events of no photon detected with expected from acceptance for all events with PART bank
Error creating thumbnail: File missing
Ratio of the events of no photon detected to all events (red) and expected events to all events (blue) with PART bank
Error creating thumbnail: File missing
Compare the events of no photon detected with expected from acceptance larger than 50% with PART bank
Error creating thumbnail: File missing
Ratio of the events of no photon detected (red) and expected events (blue) to acceptance larger than 50% with PART bank
Error creating thumbnail: File missing
Compare the events of no photon detected with expected from acceptance for all events with PART bank and validating photon with missing mass squre between [-0.1,0.1]
Error creating thumbnail: File missing
Ratio of the events of no photon detected to all events (red) and expected events to all events (blue) with PART bank and validating photon with missing mass squre between [-0.1,0.1]
Error creating thumbnail: File missing
Compare the events of no photon detected with expected from acceptance larger than 50% with PART bank and validating photon with missing mass squre between [-0.1,0.1]
Error creating thumbnail: File missing
Ratio of the events of no photon detected (red) and expected events (blue) to acceptance larger than 50% with PART bank and validating photon with missing mass squre between [-0.1,0.1]

Study of the difference

Error creating thumbnail: File missing
Compare the events of no photon detected with expected from acceptance for all events with PART bank and validating photon with missing mass squre between [-0.1,0.1]
Error creating thumbnail: File missing
Ratio of the events of no photon detected to all events (red) and expected events to all events (blue) with PART bank and validating photon with missing mass squre between [-0.1,0.1]
Error creating thumbnail: File missing
Compare the events of no photon detected with expected from acceptance larger than 50% with PART bank and validating photon with missing mass squre between [-0.1,0.1]
Error creating thumbnail: File missing
Ratio of the events of no photon detected (red) and expected events (blue) to acceptance larger than 50% with PART bank and validating photon with missing mass squre between [-0.1,0.1]
Error creating thumbnail: File missing
Compare the events of no photon detected with expected from acceptance larger than 60% with PART bank and validating photon with missing mass squre between [-0.1,0.1]
Error creating thumbnail: File missing
Ratio of the events of no photon detected (red) and expected events (blue) to acceptance larger than 60% with PART bank and validating photon with missing mass squre between [-0.1,0.1]
Error creating thumbnail: File missing
Compare the events of no photon detected with expected from acceptance larger than 70% with PART bank and validating photon with missing mass squre between [-0.1,0.1]
Error creating thumbnail: File missing
Ratio of the events of no photon detected (red) and expected events (blue) to acceptance larger than 70% with PART bank and validating photon with missing mass squre between [-0.1,0.1]

Three-pion acceptance is considered

File:First try study eta acceptance.pdf

File:Compare seen expected.pdf

File:Second try study eta acceptance.pdf

This results yield 3e-3 upper limit.

A mistake.png

Compare events from CMU and JLab

First line is JLab data, second line is CMU kinfit result

run# event# proton.px py pz pip.px py pz pim.px py pz photon.eid photon.energy

43634 7520 -0.218356 0.252237 0.850728 0.219179 -0.719475 1.00864 0.099808 -0.17973 0.341651 23 3.75253

43634 7520 0.219289 -0.723163 1.01175 -0.22012 0.247369 0.848749 0.0987671 -0.179789 0.342487 23 3.76824

43634 14658 0.0711455 -0.20281 0.597634 -0.104869 0.152357 0.275508 -0.199497 -0.0941665 0.0464326 638 1.35182

43634 14658 0.0715849 -0.204999 0.602069 -0.105456 0.151199 0.276457 -0.199497 -0.094166 0.0464326 275 2.79164

43634 14953 0.176975 -0.487071 1.02445 -0.228198 -0.0155644 0.203839 0.176574 0.267612 0.14746 485 1.9536

43634 14953 0.178628 -0.490327 1.02955 -0.228806 -0.0163596 0.204688 0.177539 0.268025 0.149043 225 2.9897

Limited statistics with timing cut

timing cut at ± 1 ns

Compare mmp none expect.png

All statistics

Error creating thumbnail: File missing
50% efficiency;Red: no decay detected; Blue: expected
Error creating thumbnail: File missing
Difference between no decay detected and expected divided by all eta events of 50% efficiency

No Kin Fit

Assign the Q value of each event

Assign Q value of each event according to the missing mass and missing mass of proton.

Error creating thumbnail: File missing
Missing mass of proton vs. missing mass

The events are separated into 9 groups according to the missing mass of proton between 0.9 and 1.8 GeV.

Error creating thumbnail: File missing
Missing mass w/ missing mass of proton between 0.9 and 1.0 GeV
Error creating thumbnail: File missing
Missing mass w/ missing mass of proton between 1.0 and 1.1 GeV
Error creating thumbnail: File missing
Missing mass w/ missing mass of proton between 1.1 and 1.2 GeV
Error creating thumbnail: File missing
Missing mass w/ missing mass of proton between 1.2 and 1.3 GeV
Error creating thumbnail: File missing
Missing mass w/ missing mass of proton between 1.3 and 1.4 GeV
Error creating thumbnail: File missing
Missing mass w/ missing mass of proton between 1.4 and 1.5 GeV
Error creating thumbnail: File missing
Missing mass w/ missing mass of proton between 1.5 and 1.6 GeV
Error creating thumbnail: File missing
Missing mass w/ missing mass of proton between 1.6 and 1.7 GeV
Error creating thumbnail: File missing
Missing mass w/ missing mass of proton between 1.7 and 1.8 GeV

The result after applying this value:

Error creating thumbnail: File missing
Missing mass of proton vs. missing mass weighted
Error creating thumbnail: File missing
missing mass weighted

Finer binning

The events are separated into 75 groups according to the missing mass of proton between 0.9 and 1.8 GeV and 12 MeV per group.

The fitting results are in fitting missing mass with p pi+ pi- detected only, and fitting missing mass with all events of eta included

Missing mass of proton VS missing mass weighted

missing mass or proton weighted

Binning adjustment

The fitting itself looks good and the result from fitting is good too. The problem must come from the binning is too fine. Therefore, the number of binning changed from 75 to 30 for events with p pi+ pi- detected only.

fitting missing mass of eta with all events included (p pi+ pi- AT LEAST)

fitting missing mass of eta with p pi+ pi- detected Only

Error creating thumbnail: File missing
Error creating thumbnail: File missing

Event-based Q value

Mm.png

Mm q.png

Mmp.png

Mmp q.png

Comparison q.png

Check the validity of Q value

Error creating thumbnail: File missing
Error creating thumbnail: File missing
Error creating thumbnail: File missing
Error creating thumbnail: File missing

Accidental Photon

Error creating thumbnail: File missing
Error creating thumbnail: File missing
Error creating thumbnail: File missing
Error creating thumbnail: File missing

Reference

arxiv:1209.2469

Retrieved from "https://wiki.jlab.org/lmd/index.php?title=Invisible_decay&oldid=996"