Thursday 9 July 2015

Neutrinos Found To Switch To Elusive ‘Tau’ Flavour

First Direct Proof of Metamorphosis

Physicist have found the first direct proof of a metamorphosis between two of the known forms of neutrinos by utilising a beam shot through the Earth’s crust, which are known as `muon’ and `tau’ of basic particles.Oscillation Project with Emulsion tracking Apparatus – OPERA conducted an experiment, at the Gran Sasso underground lab in central Italy made headlines in the year 2011 after its announcement that it had identified neutrinos travelling faster than light, against Einstein’s special theory of relativity.

 However, the claim was later proved false when the researcher found various probable sources of error in the measurements. The OPERA association declared on June 15 that it had now achieved the original goal of observing the switch in neutrino flavours. According to a neutrino physicist at the University of Genoa, Marco Pallavicini, who is not a member of the OPERA collaboration, states that `it was an extremely difficult measurement that no one had done before.Three known forms of flavours, neutrino, electron, muon and tau and the particles name refer to the fact that on unusual occasion when neutrino tend to interact with protons or neutrons, they create electrons, muons or tau leptons.

T2K – First Direct Evidence of Appearance of Different Flavour

Scientists have been suspecting that neutrinos could transform from one flavour to another and various previous experiments conducted which had used known sources of certain type of neutrino have detected fewer neutrinos than what could be expected if particles had not changed flavour. The T2K experiment carried out in July 2013 envisaged the first direct evidence of the appearance of a different flavour rather than the disappearance of the original one and discovered electron neutrinos in a beam which was originally made of muon neutrinos. In the span of 2008 and 2012, a beam of muon neutrinos was shot from Europe’s particle physics lab – CERN, near Geneva, Switzerland, to the base of the Gran Sasso massif some 730 km towards the southeast where the Italian lab is carved in the rock. Some of the muon neutrinos had changed into tan neutrinos by the time the neutrinos had arrived at Gran Sasso and when these hit the lead targets in the OPERA detector, they created tau lepton according to the latest result.

Discovered 5th Tau Lepton – Experiment 

Giovanni De Lellis, a physicist at the University of Naples, also an OPERA spokesperson informed that the leptons tend to decay in just one-trillionth of a second. Although it tends to travel at almost the same speed of light, the tau lepton only runs for less than a millimetre. The short lived particles with an array of 150,000 bricks, each of which weighs around 8 kg containing 57 stacked emulsion plates, was detected by OPERA.

With the set-up having 110,000 square metres of surface area, researchers have set up an automated system in order to search the plates for microscopic streaks which could signal the fleeting presence of tau leptons. In the incomplete result which was announced last year, OPERA collaboration calculated four probable tau lepton findings not adequate in claiming a success as per the severe detection criteria of particle physics. However, the physicists have now discovered a fifth tau lepton adequate for the experiment to be considered as successful.

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