OPERA Experiment Research Articles

The Oscillation Project with Emulsion-Tracking Apparatus (OPERA) experiment: An argument for superluminal velocities?

The Oscillation Project with Emulsion-Tracking Apparatus (OPERA) experiment is regarded by some as an empirical confirmation of the special theory of relativity (STR). It is shown that this opinion is mistaken because STR cannot exclude superluminal velocities. Einstein's derivation of the Lorentz transformation was based on a contradiction, which can be reduced mathematically to þ¼� . His premise that the speed of light in a vacuum is constant, independent of the motion of its source, is self-contradicting. Hence, by the laws of mathematics, every inference drawn from it is arbitrary, which includes that the speed of light cannot be exceeded. This inference has also been empirically refuted through the results of certain experiments on quantum mechanics, which can only be explained by either admitting superluminal velocities or by admitting miracles (action at a distance). The problems of light cannot be solved at the level of mathematics, but only at the level of physics through a new theory explaining the properties of light by physical parameters. 2012 Physics Essays Publication. (DOI: 10.4006/0836-1398-25.3.397) Resum ´ e: Les r ´ esultats trouv ´ es par l'exp ´

System for processing emulsion data of the OPERA experiment using the PAVICOM facility and prospects of its application to scan objects by muon radiography methods

The last data on the search results for neutrino oscillations in the OPERA experiment and the completed modernization of the PAVICOM facility (Lebedev Physical Institute) for automatic processing of nuclear emulsions of this experiment are presented. A new test application is developed for the PAVICOM to perform all stages of image processing. The application is tested using a GTX570 video card. The processing time for one frame is significantly reduced, which made it possible tomore than tenfold speed up processing. This is of crucial importance not only for prompt acquisition of statistically significant data of the OPERA experiment, but also for planned works on muon radiography.

Testing the special relativity theory with neutrino interactions

A recent measurement of the neutrino velocity by the OPERA experiment and the prediction of energy loss of superluminal neutrinos via the pair creation process ν → νe+e− stimulated a search of isolated e+e− pairs in detectors with good tracking capability traversed by a large flux of high-energy neutrinos like NOMAD. NOMAD has already searched for similar topologies. These results can be reinterpreted to provide stringent limits on special-relativity-violating parameters separately for each ν species.

Time-Shift in the OPERA Setup: Proof against Superluminal Neutrinos without the need of knowing the CERN-LNGS distance and Reminiscences on the Origin of the Gran Sasso Lab, of the Third Neutrino and of the "Teramo Anomaly"

The LVD time stability allows one to establish a time-shift in the OPERA experiment, thus providing the first proof against superluminal neutrinos, using the horizontal muons of the "Teramo Anomaly." This proof is particularly interesting because it does not need the knowledge of the distance between the location at which the neutrinos are produced (CERN) and the location they are detected (LNGS). Since the superluminal neutrinos generated in the physics community a vivid interest in good and bad behavior in physics research, the author thought it was appropriate to recall the origin of the Gran Sasso Lab, of the third neutrino, of the horizontal muons due to the "Teramo Anomaly" and of the oscillation between leptonic flavors, when the CERN-Gran Sasso neutrino beam was included in the project for the most powerful underground laboratory in the world.

ERRATUM: "TIME-SHIFT IN THE OPERA SETUP: PROOF AGAINST SUPERLUMINAL NEUTRINOS WITHOUT THE NEED OF KNOWING THE CERN–LNGS DISTANCE AND REMINISCENCES ON THE ORIGIN OF THE GRAN SASSO LAB, OF THE THIRD NEUTRINO AND OF THE "TERAMO ANOMALY""

The LVD time stability allows one to establish a time-shift in the OPERA experiment, thus providing the first proof against superluminal neutrinos, using the horizontal muons of the Teramo Anomaly. This proof is particularly interesting since it does not need the knowledge of the distance between the location at which the neutrinos are produced (CERN) and the location they are detected (LNGS). Since the superluminal neutrinos generated in the physics community a vivid interest in good and bad behavior in physics research, the author thought it was appropriate to recall the origin of the Gran Sasso Lab, of the third neutrino, of the horizontal muons due to the Teramo Anomaly and of the oscillation between leptonic flavors, when the CERN–Gran Sasso neutrino beam was included in the project for the most powerful underground laboratory in the world.

Measurement of the cosmic ray muon charge ratio with the OPERA detector

The OPERA detector at the Gran Sasso underground laboratory (LNGS) was used to measure the cosmic ray muon charge ratio Rμ=Nμ+/Nμ− in the TeV energy region. Rμ is shown as a function of the “vertical surface energy” Eμcosθ. A fit to a simplified model of muon production in atmosphere allowed the determination of the pion and kaon charge ratios weighted by the cosmic ray energy spectrum.

The CNGS Neutrino Beam: performance summary and future prospects

The CNGS facility completes in 2010 its third year of physics with 9.39 1019 protons delivered on target and with the first ντ event observed in the OPERA experiment [N. Agafonova, Observation of a first ντ candidate in the OPERA experiment in the CNGS beam, Tech. Rep. arXiv:1006.1623 (Jun 2010)]. The experience gained in operating this 500 kW neutrino beam facility, highlights of the beam performance and future prospects will be briefly discussed here.

Observation of a first [formula omitted] candidate event in the OPERA experiment in the CNGS beam

The OPERA experiment is aimed to prove the existence of νμ→ντ oscillation through the observation of the tau decay topology in ντ CC interactions. The physics run started in 2008 and, since then, the lead-emulsion target has been exposed to the CNGS neutrino beam every year, from spring to autum. Untill now, 1921 neutrino interaction vertices have been located and the decay search analysis has been completed for 1088 of them. One tau neutrino candidate has been found. Here, the event location and decay search procedures will be described and the tau neutrino candidate is presented.

OPERA: Electronic Detectors

The OPERA detector aims to see ντ appearance in the CNGS νμ beam as a result of neutrino oscillations. It is a hybrid detector consisting of both nuclear emulsions and electronic detectors that are discribed in this poster.

The Emulsion Scanning System of the OPERA experiment

The target unit of the OPERA detector, the so called brick, is made of lead plates acting as the neutrino target interleaved with nuclear emulsion films acting as trackers with micrometric accuracy. In this paper we report the nuclear emulsion analysis chain, from the confirmation of the electronic detector trigger for the brick tagging to the neutrino interaction vertex location and reconstruction.

Tachyonic field theory and neutrino mass running

Abstract In this paper three things are done. (i) We investigate the analogues of Cerenkov radiation for the decay of a superluminal neutrino and calculate the Cerenkov angles for the emission of a photon through a W loop, and for a collinear electron-positron pair, assuming the tachyonic dispersion relation for the superluminal neutrino. The decay rate of a freely propagating neutrino is found to depend on the shape of the assumed dispersion relation, and is found to decrease with decreasing tachyonic mass of the neutrino. (ii)We discuss a few properties of the tachyonic Dirac equation (symmetries and plane-wave solutions), which may be relevant for the description of superluminal neutrinos seen by the OPERA experiment, and discuss the calculation of the tachyonic propagator. (iii) In the absence of a commonly accepted tachyonic field theory, and in view of an apparent “running” of the observed neutrino mass with the energy, we write down a model Lagrangian, which describes a Yukawa-type interaction of a neutrino coupling to a scalar background field via a scalar-minus-pseudoscalar interaction. This constitutes an extension of the standard model. If the interaction is strong, then it leads to a substantial renormalization-group “running” of the neutrino mass and could potentially explain the experimental observations.

TIME-SHIFT IN THE OPERA SETUP: PROOF AGAINST SUPERLUMINAL NEUTRINOS WITHOUT THE NEED OF KNOWING THE CERN–LNGS DISTANCE AND REMINISCENCES ON THE ORIGIN OF THE GRAN SASSO LAB, OF THE THIRD NEUTRINO AND OF THE "TERAMO ANOMALY"

The LVD time stability allows one to establish a time-shift in the OPERA experiment, thus providing the first proof against superluminal neutrinos, using the horizontal muons of the "Teramo Anomaly." This proof is particularly interesting since it does not need the knowledge of the distance between the location at which the neutrinos are produced (CERN) and the location they are detected (LNGS). Since the superluminal neutrinos generated in the physics community a vivid interest in good and bad behavior in physics research, the author thought it was appropriate to recall the origin of the Gran Sasso Lab, of the third neutrino, of the horizontal muons due to the "Teramo Anomaly" and of the oscillation between leptonic flavors, when the CERN–Gran Sasso neutrino beam was included in the project for the most powerful underground laboratory in the world.

Development of an automated nuclear emulsion analyzing system

Abstract This paper describes the development of an automated nuclear emulsion analyzing system, which is constructed of the following three parts, the nuclear emulsion “OPERA film”, the latest automated scanning system “S-UTS” and the three-dimensional track reconstruction software “NETSCAN”. The system is able to operate at a speed of 72 cm 2 /h and overcame the bottleneck of long time-consuming to recognize tracks in the nuclear emulsion by human eyes. The system is essential for the OPERA experiment, muon radiography, gamma-ray telescope and many other fields with nuclear emulsion.

Determination of a time-shift in the OPERA set-up using high-energy horizontal muons in the LVD and OPERA detectors

The purpose of this work is to report the measurement of a time-shift in the OPERA set-up in a totally independent way from Time Of Flight (TOF) measurements of CNGS neutrino events. The LVD and OPERA experiments are both installed in the same laboratory: LNGS. The relative position of the two detectors, separated by an average distance of ~ 160 m, allows the use of very high energy horizontal muons to cross-calibrate the timing systems of the two detectors, using a TOF technique which is totally independent from TOF of CNGS neutrino events. Indeed, the OPERA-LVD direction lies along the so-called "Teramo anomaly", a region in the Gran Sasso massif where LVD has established, many years ago, the existence of an anomaly in the mountain structure, which exhibits a low m. w. e. thickness for horizontal directions. The "abundant" high-energy horizontal muons (nearly 100 per year) going through LVD and OPERA exist because of this anomaly in the mountain orography. The total live time of the data in coincidence correspond to 1200 days from mid 2007 until March 2012. The time coincidence study of LVD and OPERA detectors is based on 306 cosmic horizontal muon events and shows the existence of a negative time shift in the OPERA set-up of the order of deltaT(AB) = - (73 \pm 9) ns when two calendar periods, A and B, are compared. This result shows a systematic effect in the OPERA timing system from August 2008 until December 2011. The size of the effect is comparable with the neutrino velocity excess recently measured by OPERA. It is probably interesting not to forget that with the MRPC technology developed by the ALICE Bologna group the TOF world record accuracy of 20 ps was reached. That technology can be implemented at LNGS for a high precision determination of TOF with the CNGS neutrino beams of an order of magnitude smaller than the value of the OPERA systematic effect.

Background-dependent Lorentz violation: natural solutions to the theoretical challenges of the superluminal neutrino propagation

To explain both the OPERA experiment and all the known phenomenological constraints/observations on Lorentz violation, the Background Dependent Lorentz Violation (BDLV) has been proposed. We study the BDLV in a model independent way, and conjecture that there may exist a "Dream Special Relativity Theory", where all the Standard Model (SM) particles can be subluminal due to the background effects. Assuming that the Lorentz violation on the Earth is much larger than those on the interstellar scale, we automatically escape all the astrophysical constraints on Lorentz violation. For the BDLV from the effective field theory, we present a simple model and discuss the possible solutions to the theoretical challenges of the OPERA experiment such as the Bremsstrahlung effects for muon neutrinos and the pion decays. Also, we address the Lorentz violation constraints from the LEP and KamLAMD experiments. For the BDLV from the Type IIB string theory with D3-branes and D7-branes, we point out that the D3-branes are flavour blind, and all the SM particles are the conventional particles as in the traditional SM when they do not interact with the D3-branes. Thus, we not only can naturally avoid all the known phenomenological constraints on Lorentz violation, but also can naturally explain all the theoretical challenges. Interestingly, the energy dependent photon velocities may be tested at the experiments.

SU-E-T-234: LET Measurement Using Nuclear Emulsion and Monte Carlo Simulation for Proton Beam.

The significant issue of particle therapy such as proton and carbon ion biological effect on tumors and normal tissue. This effect closely connected with linear-energy-transfer (LET). This work presents a Monte Carlo study using GEANT4 and the verification using Nuclear Emulsion to show LET for proton beam. National Cancer Center (NCC) has IBA Beam Nozzle and cyclotron for proton therapy. We use proton beam bragg peak range 14cm. Also, we already developed the simulation using GEANT4 and finished validation for scattering proton beam. In our simulation, we make same condition with experimental setup.Nuclear emulsion films interleaved with tissue equivalent absorbers can be fruitfully used to reconstruct proton tracks with very high precision. This Nuclear emulsion film has been supported from Nagoya University, analyzed in Pusan University, was irradiated with a therapeutic proton beam at NCC. The Emulsion packs was located at entrance and bragg peak region of proton. This position means low and high LET region. The scanning of the emulsions has been performed at Nagoya University, where a fully automated microscopic scanning technology has been developed for the OPERA experiment on neutrino oscillations. We could see the reconstructed track of proton scanning emulsion. From film scanning, we got the LET distribution at low and high LET region for several proton tracks. Simulation results was similar distribution within standard deviation in acceptance level. Also we got the RBE distribution using LET measurement for proton beam. We measured LET at entrance and bragg peak region using Monte Carlo study and Nuclear Emulsion film, for NCC proton beam. This results means the good observation of LET using the nuclear emulsion. And this method can be used successfully in medical field.

Neutrinos with velocities greater thanc?

A possible explanation of the results of the OPERA experiment is presented. Assuming that the usual value of c should be interpreted as the velocity of light in dark matter, we call the "true" velocity of light in vacuum, $c_t$. Then the OPERA neutrinos can be faster than c but slower than $c_t$. We also discuss the relationship between $c_t$ and neutrino masses.

SUPERLUMINAL NEUTRINOS FROM SPECIAL RELATIVITY WITH DE SITTER SPACETIME SYMMETRY

We explore the recent OPERA experiment of superluminal neutrinos in the framework of special relativity with de Sitter spacetime symmetry (dS-SR). According to Einstein, a photon is treated as a massless particle in the framework of special relativity. In special relativity (SR) we have the universal parameter c, the photon velocity c photon and the phase velocity of a light wave in vacuum c wave = λν. Due to the null experiments of Michelson–Morley we have c = c wave . The parameter c photon is determined by the Noether charges corresponding to the spacetime symmetries of SR. In Einstein's special relativity (E-SR) we have c = c photon . In dS-SR, i.e. the special relativity with SO(4, 1) de Sitter spacetime symmetry, we have c photon > c. In this paper, the OPERA datum are examined in the framework of dS-SR. We show that OPERA anomaly is in agreement with the prediction of dS-SR with R≃1.95×1012 l.y. Based on the p-E relation of dS-SR, we also prove that the Cohen and Glashow's argument of possible superluminal neutrino's Cherenkov-like radiation is forbidden. We conclude that OPERA and ICARUS results are consistent and they are explained in the dS-SR framework.

Constraints from orbital motions around the Earth of the environmental fifth-force hypothesis for the OPERA superluminal neutrino phenomenology

It has been recently suggested by Dvali and Vikman that the superluminal neutrino phenomenology of the OPERA experiment may be due to an environmental feature of the Earth, naturally yielding a long-range fifth force of gravitational origin whose coupling with the neutrino is set by the scale M_*, in units of reduced Planck mass. Its characteristic length lambda should not be smaller than one Earth's radius R_e, while its upper bound is expected to be slightly smaller than the Earth-Moon distance (60 R_e). We analytically work out some orbital effects of a Yukawa-type fifth force for a test particle moving in the modified field of a central body. Our results are quite general since they are not restricted to any particular size of lambda; moreover, they are valid for an arbitrary orbital configuration of the particle, i.e. for any value of its eccentricity $e$. We find that the dimensionless strength coupling parameter alpha is constrained to |alpha| <= 1 10^-10-4 10^-9 for 1 R_e <= lambda <= 10 R_e by the laser data of the Earth's artificial satellite LAGEOS II, corresponding to M_* >= 4 10^9 -1.6 10^10. The Moon perigee allows to obtain |alpha| <= 3 10^-11 for the Earth-Moon pair in the range 15 R_e <= lambda <= 60 R_e, which translates as M_* >= 3 10^10 - 4.5 10^10. Our results are neither necessarily limited to the superluminal OPERA scenario nor to the Dvali-Vikman model, in which it is M_* = 10^-6 at lambda = 1 R_e, in contrast with our bounds: they generally extend to any theoretical scenario implying a fifth-force of Yukawa-type.

A note on superluminal neutrinos

Although characterized by a possible experimental error, the first results of the Opera experiment at CERN have opened up a hot discussion on the possibility of superluminal neutrinos already observed in some space events. In particular, Cohen and Glashow (CG) have considered it simply an error justifying their position on the basis of the bremsstrahlung of electron-positron pairs. In this paper, we would like to discuss this position also in view of the recent derivation of the superluminal limit as a consequence of the classical causality principle. Even if the final answer is related only to the review of all the experimental results, we believe that neutral particles (neutrinos, photons, etc.) might exhibit superluminal behavior also in view of the fact that the analysis performed by Cohen and Glashow does not contain any absolute limit, like that present in the case of the Cherenkov effect in vacuum, which is absolutely impossible, as its violation would require an infinite energy amount. CG conclusions are not in contrast with superluminal neutrinos, which, in turn, are fully compatible with the theoretical analysis reported as well.