OPERA tau neutrino candidate event 12254000036

Description

This neutrino interaction occurred on September $9^{th}$ 2012 in the second super-module, in the $21^{st}$ wall, 10~brick walls upstream of the spectrometer. No muon was identified by the reconstruction of the data provided by electronic detectors. The interaction was fully reconstructed in the brick, looking for tracks within an angular acceptance defined by $\tan \vartheta = 3$.

The analysis of the interface emulsion films revealed a converging path of 10 tracks, so the corresponding brick was extracted and developed. By following back these tracks with the scan-back method, the neutrino interaction was located in the lead plate between the 39$^{th}$ and 40$^{th}$ emulsion films. The primary vertex is defined by four tracks, one of which shows a kink topology. In addition, two electromagnetic showers originated by the conversion of ${\gamma}$-rays were detected, both pointing to the primary vertex.

The $\tau$ candidate decays after a flight length of ${(1090 \pm 30)}$~${\mu}$m with a ${\theta_{kink}}$ of ${(137 \pm 4)}$~mrad. It was followed in the downstream bricks till it exited the target, stopping in the spectrometer after leaving a signal in three Resistive Plate Chamber planes. All primary and secondary 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. One of the primary particles was identified as a proton, while another one undergoes an interaction just before entering the second downstream brick, producing a 2-prong vertex. The neutrino energy was measured to be $(14.4^{+3.9}_{-2.7})$~GeV/c.

This event was thus interpreted as a $\nu_{\tau}$ charged-current interaction with the $\tau$ lepton decaying into a single hadron. A detailed description of the event is given in 10.1093/ptep/ptu132

Related datasets

This event is part of OPERA Electronic Detector tau appearance dataset

Electronic detector data for tau neutrino appearance studies

This event is part of OPERA Emulsion Detector tau appearance dataset

Emulsion data for neutrino tau appearance studies

Dataset characteristics

1 events. 14 files. 16.4 kB in total.

Dataset semantics

Variable	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

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Visualise OPERA detector event 12254000036

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