Studiesof CosmogenicBackgroundto( NucleonDecayin MicroBooNE · Motivations for Nucleon Decay...
Transcript of Studiesof CosmogenicBackgroundto( NucleonDecayin MicroBooNE · Motivations for Nucleon Decay...
Studies of Cosmogenic Background to Nucleon Decay in MicroBooNE
Elena Gramellini -‐‑ Yale University On behalf of the MicroBooNE collaboration
TAUP 2015 September 6-‐‑11, Torino, Italy
Motivations for Nucleon Decay
Every interaction in the SM conserves baryon number.
Proton (or bound neutron) decay can occur only as a violation of baryon number and it’s predicted by almost every GUT.
08/09/15 Elena Gramellini YaleU – TAUP 2015 2
The detection of even one nucleon decay event would be a direct evidence of physics BSM,
opening a window on GUTs exploration.
Not Only Golden Modes
… plus many others!
08/09/15 Elena Gramellini YaleU – TAUP 2015 3
arXiv:1307.7335
p → e+π0 p → K+ ν
The discovery of a particular decay mode would constrain GUT models.
Need of experimental handle on many different predicted modes.
Experimental Limits on τP
08/09/15 Elena Gramellini YaleU – TAUP 2015 4
1032
1033
1034
Soudan Frejus Kamiokande IMB
τ/B (years)
Super-K
p → e+ π0
p → μ+ ρ0
n → ν ω
p → e+ K 0
n → e+ K -
n → μ+ K -
p → ν K +
n → ν K 0
p → e+ K*(892)0
n → ν K*(892)0
p → ν K*(892)+
p → μ+ π0
n → μ+ π-
p → ν π+
n → ν π0
p → e+ η
p → μ+ η
n → ν η
p → e+ ρ0
n → e+ ρ-
n → ν ρ0
p → e+ ω
p → μ+ ω
n → e+ π-
n → μ+ ρ-
p → ν ρ+
p → μ+ K 0
1035
n → e- K +
Ed. Kearns
A Tool for Many Modes: LArTPC
08/09/15 Elena Gramellini YaleU – TAUP 2015 5
Working principles of a Liquid Argon Time Projection Chamber: 1. Charged particles interact in Ar
• Produce scintillation light • Ionize electrons
2. Ionization e-‐‑ drift to anode 3. Wire planes detect drift e-‐‑
Cathode plate Anode plane Electric Field
X
Y
Scintillation Light detected by PMTs
Drift Time = X position
Charge collected by wire plane
Electrons
LArTPC Key Features for Nucleon Decay
08/09/15 Elena Gramellini YaleU – TAUP 2015 6
U plane induction
V plane induction
Y plane collection
⊕ ⊕ =⊕ Drift time 3D imaging Millimetric
Space Resolution
One of first MicroBooNE events
Wire pitch at the millimeter scale.
Calorimetry information
Ingredients for Nucleon Decay Detection
Lots of nucleons Lots of time
Low background [so low you need to go underground?]
08/09/15 Elena Gramellini YaleU – TAUP 2015 7
08/09/15 Elena Gramellini YaleU – TAUP 2015 8
Future and present LArTPCs…
X4
DUNE: Increase Nucleon Decay sensitivity in multiple channels.
40K ton active volume
08/09/15 Elena Gramellini YaleU – TAUP 2015 9
Future and present LArTPCs…
X4
DUNE: Increase Nucleon Decay sensitivity in multiple channels.
40K ton active volume
08/09/15 Elena Gramellini YaleU – TAUP 2015 10
Future and present LArTPCs…
Study Cosmogenic Backgrounds in a LArTPC. X4
DUNE: Increase Nucleon Decay sensitivity in multiple channels.
89 ton active volume
40K ton active volume
MicroBooNE and Nucleon Decay
GOAL Perform a topological search of events that mimic proton decay to estimate the mis-‐‑id
rate from cosmogenic sources.
1. Study the decay topologies by exploiting the variety of information provided by a LArTPC.
2. Development of a selection strategy geared towards removal of cosmogenic backgrounds for proton decay.
08/09/15 Elena Gramellini YaleU – TAUP 2015 11
08/09/15 Elena Gramellini YaleU – TAUP 2015 12
p → e+π0
Standard candle
p → µμ+γ High background
channel
p → K+ ν Golden channel
in LAr
Some example modes
08/09/15 Elena Gramellini YaleU – TAUP 2015 13
p → e+π0 Standard candle
p → µμ+γ High background
channel
p → K+ ν Golden channel
in LAr
Some example modes
08/09/15 Elena Gramellini YaleU – TAUP 2015 14
p → e+π0 Standard candle
p → µμ+γ High background
channel
p → K+ ν Golden channel
in LAr
Some example modes
08/09/15 Elena Gramellini YaleU – TAUP 2015 17
Selection strategy
Geometry selection & PID – π0 and e identification – No additional vertex activity – Proximity – Planarity
Calorimetry selection – Total energy deposited consistent with the proton rest mass
– Total net momentum consistent with Fermi Momentum
e
γ γ
08/09/15 Elena Gramellini YaleU – TAUP 2015 18
Selection strategy
e
γ γ
Geometry selection & PID – π0 and e identification – No additional vertex activity – Proximity – Planarity
Calorimetry selection – Total energy deposited consistent with the proton rest mass
– Total net momentum consistent with Fermi Momentum
08/09/15 Elena Gramellini YaleU – TAUP 2015 19
Selection strategy
e
γ γ
Geometry selection & PID – π0 and e identification – No additional vertex activity – Proximity – Planarity
Calorimetry selection – Total energy deposited consistent with the proton rest mass
– Total net momentum consistent with Fermi Momentum
θ
20 08/09/15 Elena Gramellini YaleU – TAUP 2015
Selection strategy: Geometry & PID
Geometry selection & PID π0 identification e identification No additional vertex activity Proximity Planarity Calorimetry selection Total Energy deposited Total net momentum
We look for events that meet all the selection criteria: important background.
21 08/09/15 Elena Gramellini YaleU – TAUP 2015
Selection strategy: Geometry & PID
✔
✔ Geometry selection & PID π0 identification e identification No additional vertex activity Proximity Planarity Calorimetry selection Total Energy deposited Total net momentum
We look for events that meet all the selection criteria: important background.
Geometry selection & PID π0 identification e identification No additional vertex activity Proximity Planarity Calorimetry selection Total Energy deposited Total net momentum
22 08/09/15 Elena Gramellini YaleU – TAUP 2015
Selection strategy: Geometry & PID
✔ ✖ ✖
✖ ✖
✖ ✖ ✔
✔
We look for events that meet all the selection criteria: important background.
23 08/09/15 Elena Gramellini YaleU – TAUP 2015
Selection strategy: Calorimetry
Geometry selection & PID π0 identification e identification No additional vertex activity Proximity Planarity Calorimetry selection Total Energy deposited Total net momentum
We look for events that meet all the selection criteria: important background.
24 08/09/15 Elena Gramellini YaleU – TAUP 2015
Selection strategy: Calorimetry
Geometry selection & PID π0 identification e identification No additional vertex activity Proximity Planarity Calorimetry selection Total Energy deposited Total net momentum
✔
✔ ✔ ✔
We look for events that meet all the selection criteria: important background.
25 08/09/15 Elena Gramellini YaleU – TAUP 2015
Selection strategy: Calorimetry
Geometry selection & PID π0 identification e identification No additional vertex activity Proximity Planarity Calorimetry selection Total Energy deposited Total net momentum
✔
✖ ✖
✔ ✔ ✔
We look for events that meet all the selection criteria: important background.
08/09/15 Elena Gramellini YaleU – TAUP 2015 26
p → e+π0 Standard candle
p → µμ+γ High bkg channel
p → K+ ν Golden channel
in LAr
Some example modes
28 08/09/15 Elena Gramellini YaleU – TAUP 2015
Simulated Event Display for p → μ+ γ with cosmics data overlay
29 08/09/15 Elena Gramellini YaleU – TAUP 2015
Simulated Event Display for p → μ+ γ with cosmics data overlay
30 08/09/15 Elena Gramellini YaleU – TAUP 2015
µμ
γ
Simulated Event Display for p → μ+ γ with cosmics data overlay
08/09/15 Elena Gramellini YaleU – TAUP 2015 31
Selection strategy
Geometry selection & PID – µμ/π and γ identification – No additional vertex activity – Proximity – Planarity
Calorimetry selection – Total energy deposited consistent with the proton rest mass
– Total net momentum consistent with Fermi Momentum
Fiducialization γ
µμ
08/09/15 Elena Gramellini YaleU – TAUP 2015 32
Selection strategy
γ
µμ Geometry selection & PID – µμ/π and γ identification – No additional vertex activity – Proximity – Planarity
Calorimetry selection – Total energy deposited consistent with the proton rest mass
– Total net momentum consistent with Fermi Momentum
Fiducialization
08/09/15 Elena Gramellini YaleU – TAUP 2015 33
Selection strategy
θ
γ
µμ Geometry selection & PID – µμ/π and γ identification – No additional vertex activity – Proximity – Planarity
Calorimetry selection – Total energy deposited consistent with the proton rest mass
– Total net momentum consistent with Fermi Momentum
Fiducialization
34 08/09/15 Elena Gramellini YaleU – TAUP 2015
Selection strategy: geometry
Geometry selection & PID µμ/π identification γ identification No additional vtx activity Proximity Planarity
Calorimetry selection Total energy deposited Total net momentum Fiducialization
We look for events that meet all the selection criteria:
important background.
35 08/09/15 Elena Gramellini YaleU – TAUP 2015
Selection strategy: geometry
Geometry selection & PID µμ/π identification γ identification No additional vtx activity Proximity Planarity
Calorimetry selection Total energy deposited Total net momentum Fiducialization
✔
✔
We look for events that meet all the selection criteria:
important background.
36 08/09/15 Elena Gramellini YaleU – TAUP 2015
Selection strategy: geometry
Geometry selection & PID µμ/π identification γ identification No additional vtx activity Proximity Planarity
Calorimetry selection Total energy deposited Total net momentum Fiducialization
✖
✔ ✖
✔ ✖ ✔
We look for events that meet all the selection criteria:
important background.
Selection strategy: calorimetry
37 08/09/15 Elena Gramellini YaleU – TAUP 2015
Geometry selection & PID µμ/π identification γ identification No additional vtx activity Proximity Planarity
Calorimetry selection Total energy deposited Total net momentum Fiducialization
We look for events that meet all the selection criteria:
important background.
Selection strategy: calorimetry
38 08/09/15 Elena Gramellini YaleU – TAUP 2015
Geometry selection & PID µμ/π identification γ identification No additional vtx activity Proximity Planarity
Calorimetry selection Total energy deposited Total net momentum Fiducialization
✔
✔
✔
We look for events that meet all the selection criteria:
important background.
Selection strategy: calorimetry
39 08/09/15 Elena Gramellini YaleU – TAUP 2015
Geometry selection & PID µμ/π identification γ identification No additional vtx activity Proximity Planarity
Calorimetry selection Total energy deposited Total net momentum Fiducialization
✔
✖ ✖
✔ ✖ ✔
We look for events that meet all the selection criteria:
important background.
p → μ+ γ signature in 2D
40 08/09/15 Elena Gramellini YaleU – TAUP 2015
Geometry selection & PID µμ/π identification γ identification No additional vtx activity Proximity Planarity
Calorimetry selection Total energy deposited Total net momentum Fiducialization
We look for events that meet all the selection criteria:
important background.
p → μ+ γ signature in 2D
41 08/09/15 Elena Gramellini YaleU – TAUP 2015
Geometry selection & PID µμ/π identification γ identification No additional vtx activity Proximity Planarity
Calorimetry selection Total energy deposited Total net momentum Fiducialization
✔
✔ ✔
✔ ✔ ✔
We look for events that meet all the selection criteria:
important background.
p → μ+ γ signature in 2D
42 08/09/15 Elena Gramellini YaleU – TAUP 2015
Geometry selection & PID µμ/π identification γ identification No additional vtx activity Proximity Planarity
Calorimetry selection Total energy deposited Total net momentum Fiducialization
✔
✔ ✔
✔ ✔ ✔
We look for events that meet all the selection criteria:
important background.
p → μ+ γ signature in 2D
43 08/09/15 Elena Gramellini YaleU – TAUP 2015
Geometry selection & PID µμ/π identification γ identification No additional vtx activity Proximity Planarity
Calorimetry selection Total energy deposited Total net momentum Fiducialization
✔
✔ ✔
✔ ✔ ✔
?
?
We look for events that meet all the selection criteria:
important background.
Selection strategy: fiducialization
44 08/09/15 Elena Gramellini YaleU – TAUP 2015
The shower activity of the event is very close to the edge of the TPC: event rejected by planarity and fiducialization.
Selection strategy: fiducialization
45 08/09/15 Elena Gramellini YaleU – TAUP 2015
The shower activity of the event is very close to the edge of the TPC: event rejected by planarity and fiducialization.
08/09/15 Elena Gramellini YaleU – TAUP 2015 46
In the first MicroBooNE events, we’ve seen…
Visual summary
08/09/15 Elena Gramellini YaleU – TAUP 2015 49
In the first MicroBooNE events, we’ve seen… … and more to come!
TakeawaysEven in the initial MicroBooNE cosmics data, we are
seeing for the first time topologies of interest for proton decay searches in a LAr.
This analysis is in progress.
The goal is to produce full characterization and analysis of cosmogenic backgrounds mis-‐‑ID rates.
With MicroBooNE (a 100 ton scale experiment), we can measure backgrounds, as well as develop strategies and reconstruction tools critical for future
LArTPCs proton decay searches.
08/09/15 Elena Gramellini YaleU – TAUP 2015 50
08/09/15 Elena Gramellini YaleU – TAUP 2015 51
Thanks for the aqention!
… if you want to hear more about MicroBooNE, don’t forget to aqend our
run coordinator‘s (Maq Toups) talk tomorrow!
53
Simulated Event Display for the p → K+ν ̄
08/09/15 Elena Gramellini YaleU – TAUP 2015
Event display of a simulated p → K+ν proton decay mode.
08/09/15 Elena Gramellini YaleU – TAUP 2015 54
MicroBooNE is a 170 ton LArTPC in the Booster Neutrino Beam at Fermilab.
While the mass is not sufficient to explore τP not already excluded. Surface position and currently taking cosmic
data: perfect venue to study
Cosmogenic Backgrounds in a LArTPC.
Test the potential of LArTPC in proton decay
searches.
…What About Now?
Y: 232 cm
X: 256 cm