Neutrino : Faster than light. Isthat true?
Abstract :
Researchers on the Opera(Oscillation Project with Emulsion-tRackingApparatus) experiment recorded the arrivaltimes of ghostly subatomic particles calledneutrinos sent from Cern on a 730km journeythrough the Earth to the Gran Sasso lab. Themeasurement amounts to the neutrinostravelling faster than the speed of light by afraction of 20 parts per million. Scientistsdiscovered that the particles were arriving 60nanoseconds faster than the speed of light,with only a 10 millisecond error margin
1. Introduction :
The neutrino
was first postulated in 1930 byWolfgang Paulito preserve theconservation ofenergy, conservation of momentum,and conservation of angular momentuminbetadecay.This was done by adding anundetected particle that Pauli termed a"neutron" to theprotonandelectronalready known to be products of beta decay:n
+ e
 He theorized that an undetected particle wascarrying away the observed differencebetween theenergy,momentum,andangular momentumof the initial and final particles.The speed of
299,792,458 metres persecond
, the
were evidentlytravelling at
299,798,454 metres per second
.CERN scientists using a 1180-tonne particledetector have measured particles travellingfaster than the speed of light. If confirmed, this
discovery could invalidate Albert Einstein’s
1905 theory of special relativity andrevolutionise physics.Most neutrinos passing through the Earthemanate from the Sun. About 65 billion(6.5×10
) solar neutrinos per second passthrough every square centimeter perpendicularto the direction of the Sun in the region of theEarth.
2. Principle of the neutrino time of flightmeasurement by OPERA
The time of flight of CNGS neutrinos (TOFν)
cannot be precisely measured at the singleinteraction level since any proton in the 10.5
μs extraction time may produce the neutrino
 detected by OPERA. However, by measuringthe time distributions of protons for eachextraction for which neutrino interactions areobserved in the detector, and summing themtogether, after proper normalisation oneobtains the probability density function (PDF)of the time of emission of the neutrinos withinthe duration of extraction. Each protonwaveform is UTC time-stamped as well as theevents detected by OPERA. The two time-stamps are related by TOFc, the expectedtime of flight assuming the speed of light [K.Nakamura, 2010]. It is worth stressing that thismeasurement does not rely on the differencebetween a start (t0) and a stop signal but onthe comparison of two event time distributions.The PDF distribution can then be comparedwith the time distribution of the interactionsdetected in OPERA, in order to measure
TOFν. The deviation δt = TOFc
TOFν is
obtained by a maximum likelihood analysis ofthe time tags of the OPERA events withrespect to the PDF, as a
function of δt. The
individual measurement of the waveformsreflecting the time structure of the extractionreduces systematic effects related to timevariations of the beam compared to the casewhere the beam time structure is measured onaverage, e.g. by a near neutrino detectorwithout using proton waveforms.
Figure above shown schematic of the time of flight measurement.
3. Conslusion :
Neutrinos can travel faster than light maybe iscorrect. Some scientists in attendance at thelive seminar voiced concerns with theexperiments methodolody, in particular itsreliance on GPS technology, which couldn'tdirectly measure the target location, since itwas underground. One of the seminar
attendees suggested digging a hole to addressthe issue, but then the target wouldn't havebeen shielded from cosmic rays, which alsocould have affected the results.Other researcher labs are planning newexperiments to see if they can duplicate theCERN result. A notable one is Fermilab,whose previous experiments had hinted atpossible faster-than-light neutrinos.
of 2