OPERA tau neutrino candidate event 11143018505, OPERA collaboration
Cite as: OPERA collaboration (2018). OPERA tau neutrino candidate event 11143018505. CERN Open Data Portal. DOI:10.7483/OPENDATA.OPERA.QW32.245V
Dataset Derived OPERA CERN-SPS
This neutrino interaction occurred on May $23^{rd}$ 2011 in the first super-module, 19 brick walls downstream of the spectrometer. No muon was identified by the reconstruction of the data provided by electronic detectors. All tracks possibly related to the interaction were searched for in the brick within an angular acceptance defined by $\tan\vartheta=3$.
After the analysis of interface emulsion films, 27 trigger tracks were identified and they showed a clear converging pattern; out of them 11 were found also in the brick. Several of them are clustered in a few hundreds microns area, this is an indication of electromagnetic activity related to the primary neutrino interaction. After the analysis of interface emulsion films, 27 trigger tracks were identified and they showed a clear converging pattern; out of them 11 were found also in the brick. Several of them are clustered in a few hundreds microns area, this is an indication of electromagnetic activity related to the primary neutrino interaction.
The peculiarity of this event is that it has two secondary vertices within about 1~mm from the primary one.
The neutrino vertex is defined by 3 tracks. Of the two secondary vertices, one has 2-prongs and occurs in the same lead plate of the neutrino vertex, after a flight length of $103$~$\mu$m, while the other one exhibits a kink after a flight length of $1160$~$\mu$m.
All tracks were classified as hadrons using their overall track length reconstructed along all the downstream available bricks, the topology at their end-point and the correlation between their momentum and range. The energy of the neutrino interaction was measured to be $23.2$~GeV/c.
The most probable interpretation for this event is a $\nu_\tau$ charged-current interaction with charmed hadron production. Other possibilities like a neutral-current $\nu_{\mu}$ interaction with associated charm production were discarded with a good significance using a multivariate analysis method. The most discriminating variables used were the lepton-hadron transverse angle and the daughter momentum. With respect to the non $\tau$-charm hypothesis, the observed event has a very low probability, about $10^{-4}$, which corresponds to a significance of 3.5$\sigma$.
Electronic detector data for tau neutrino appearance studies
This event is part of OPERA Emulsion Detector tau appearance datasetVariable | Description |
---|---|
amplL | PMT amplitude measured from the "left" side of a scintillator strip (in photo-electrons) |
amplR | PMT amplitude measured from the "right" side of a scintillator strip (in photo-electrons) |
amplRec | PMT amplitude reconstructed from the "left" and "right" side amplitudes of a scintillator strip taking into account light attenuation in a WLS fiber (in photo-electrons) |
clLength | cluster length (in cm) |
driftDist | drift distance (in cm) |
enHad | energy of a hadron jet (in GeV) |
enNeu | energy of a neutrino (in GeV) |
enVis | visible energy (in MeV) |
evID | event Id (10- or 11-digit number) |
globPosX | X position of a vertex in the OPERA detector system of reference (in cm) |
globPosY | Y position of a vertex in the OPERA detector system of reference (in cm) |
globPosZ | Z position of a vertex in the OPERA detector system of reference (in cm) |
muMom | momentum of a muon (in GeV/c) |
posX | For Electronic Detector events, X position of a drift tube, RPC, Target Tracker hit in the OPERA detector system of reference (in cm). For Emulsion Detector events, X position of a track/vertex in the OPERA brick system of reference (in micrometers). |
posX1 | X position of the beginning of a line in the OPERA brick system of reference (in micrometers) |
posX2 | X position of the end of a line in the OPERA brick system of reference (in micrometers) |
posY | For Electronic Detector events, Y position of an RPC hit in the OPERA detector system of reference (in cm). For Emulsion Detector events, Y position of a track/vertex in the OPERA brick system of reference (in micrometers). |
posY1 | Y position of the beginning of a line in the OPERA brick system of reference (in micrometers) |
posY2 | Y position of the end of a line in the OPERA brick system of reference (in micrometers) |
posZ | For Electronic Detector events, Z position of a drift tube, RPC, Target Tracker hit in the OPERA detector system of reference (in cm). For Emulsion Detector events, Z position of a track/vertex in the OPERA brick system of reference (in micrometers). |
posZ1 | Z position of the beginning of a line in the OPERA brick system of reference (in micrometers) |
posZ2 | Z position of the end of a line in the OPERA brick system of reference (in micrometers) |
primary | flag of a vertex: 1 - primary vertex; 0 - not primary vertex |
slopeXZ | tangent of a track angle in XZ view |
slopeYZ | tangent of a track angle in YZ view |
timestamp | event time in milliseconds since 01/01/1970 |
trType | type of a track: 1 - muon; 2 - hadron; 3 - electron/positron; 8 - tau lepton |
Demobbed-viewer is a JavaScript application developed for the CERN Open Data Portal. The application is supposed to visualise neutrino interaction events registered in the OPERA experiment.
At present OPERA open data sample includes four sub-samples (a sub-sample to display can be specified in the left part of the toolbar):
- the "nuTau" sub-sample (Electronic detector data + Emulsion data) includes 10 tau neutrino candidate events observed by OPERA in the CNGS neutrino beam.
- the "nuMu" sub-sample (Electronic detector data + Emulsion data) includes 817 events used in the study of charged hadron multiplicities in charged-current neutrino-lead interactions in the OPERA detector.
- the "nuE" sub-sample (Electronic detector data + Emulsion data) includes 19 electron neutrino candidate events registered in the OPERA detector.
- the "charm" sub-sample (Electronic detector data + Emulsion data) includes 50 charm decay candidate events registered in the OPERA detector.
Opera hybrid experimental setup (described in detail here) included Electronic detectors (ED) for real-time detection of neutrino interactions and nuclear emulsions for precision analysis of neutrino event topologies. The ED provided positions of hits in two perpendicular planes: XZ (top view) and YZ (side view). By default, only ED information is displayed in the Demobbed-viewer. After analysis of the ED data the unit of OPERA target (lead-emulsion or ECC brick) that most probably contained the neutrino interaction vertex was extracted from the detector and its emulsion data were analysed as well. 3D view of reconstructed emulsion data can be opened in the ECC display (see description below).
Brief description of available button actions:
/ - go to the previous/next event (if any) in the selected sub-sample. Also the event Id can be specified directly in the nearest edit box.
- reload the currently displayed event.
/ - zoom in/out. Please note that the default (whole detector) views of the ED display can't be zoomed out.
- move the XZ and YZ camera views to the vertex brick. ECC brick that contains the primary neutrino interaction vertex will be shown (an appropriate zooming will be adjusted automatically). The vertex position as well as projections of muon and some long hadron tracks found in the emulsion will be displayed as well.
- move the XZ and YZ camera views and adjust zooming in order to display the whole neutrino event region.
- show the whole detector region (default option).
, , , and - move the ED display camera views, correspondingly, up, down, left, and right.
The ECC display view can be rotated or moved with help of the left or right mouse buttons, correspondingly.
, , or - show the default XZ, YZ, or XY view of the event in the ECC display.
/ - stretch/compress the ECC view in the vertical (Y) direction.
- start/accelerate animated rotation of the ECC event around the Y (vertical) axis. This button can be clicked several (but not so many!) times.
- decelerate animated rotation of the ECC event. In order to stop the rotation this button has to be clicked the same number of times as the "accelerating" button has been clicked before.
A browser-based event display for visualisation of open data of the OPERA experiment.
This application uses d3.js and three.js libraries. The code is available on the GitHub repository.
Contributors: S. Dmitrievsky (JINR, Dubna, Russia), G. Tsanaktsidis (CERN, Geneva, Switzerland), M. Vidal (CERN, Geneva, Switzerland).
These OPERA event data files can be visualised using the online OPERA event display
The open data are released under the Creative Commons CC0 waiver. Neither the experiment(s) ( OPERA ) nor CERN endorse any works, scientific or otherwise, produced using these data. All releases will have a unique DOI that you are requested to cite in any applications or publications.