The temperature of the upper atmosphere affects the height of primary cosmic ray interactions and the production of high-energy cosmic ray muons which can be detected deep underground. The MINOS far detector at Soudan MN, USA, has collected over 67 million cosmic ray induced muons. The underground muon rate measured over a period of five years exhibits a 4% peak-to-peak seasonal variation which is highly correlated with the temperature in the upper atmosphere. The coefficient, $α_T$, relating changes in the muon rate to changes in atmospheric temperature was found to be: $α_T = 0.874 \pm 0.009$ (stat.) $\pm 0.010$ (syst.). Pions and kaons in the primary hadronic interactions of cosmic rays in the atmosphere contribute differently to $α_T$ due to the different masses and lifetimes. This allows the measured value of $α_T$ to be interpreted as a measurement of the K/$π$ ratio for $E_{p}\gtrsim$\unit[7]{TeV} of $0.13 \pm 0.08$, consistent with the expectation from collider experiments.
The parameters of the seasonal modulations (variations) in the intensity of muons and cosmogenic neutrons generated by them at a mean muon energy of 280 GeV have been determined in the LVD (Large Volume Detector) experiment. The modulations of muons and neutrons are caused by a temperature effect, the seasonal temperature and density variations of the upper atmospheric layers. The analysis performed here leads to the conclusion that the variations in the mean energy of the muon flux are the main source of underground cosmogenic neutron variations, because the energy of muons is more sensitive …
An observation of seasonal variations in underground muon rate, $R_μ$, has been performed at Soudan, MN, by the MINOS Far Detector. The four percent fluctuation seen over three years was highly correlated to the temperature variations of the upper atmosphere. The coefficient relating variations in temperature to variations in muon rate was found to be: $α_T = (T/R_μ)(\partial R_μ/ \partial T) = 0.87 \pm 0.03$, which is near the expectation of 0.91.
Explanation of the seasonal variation of cosmic multiple muon events observed with the NOvA Near Detector
Erciyes University（埃尔齐耶斯大学）；Universidad del Atlantico（大西洋大学）；University of Mississippi（密西西比大学）；Fermi National Accelerator Laboratory（费米国家加速器实验室）；Joint Institute for Nuclear Research（联合核研究所）；Universidad del Magdalena（马格达莱纳大学）；University of Sussex（萨塞克斯大学）；University of Cincinnati（辛辛那提大学）；Indiana University（印第安纳大学）；Iowa State University（爱荷华州立大学）；University of California at Irvine（加州大学尔湾分校）；University of Hyderabad（海得拉巴大学）
It is well known that the rate of cosmic ray muons depends on the atmospheric temperature, and that for events with a single muon the peak of the rate is in summer, in underground laboratories in the northern hemisphere. In 2015 the MINOS experiment, in USA, found that, for small distances between the multiple-muons, the rate of multiple-muons peaks in the winter and that the amplitude of the modulation is smaller than in the case of a single muon. I have done a re-analysis of data of the past MACRO experiment. The result is that under Gran Sasso the rate of multiple-muons at small distances p…
The intensity of TeV atmospheric muons and neutrinos depends on the temperature in the stratosphere. We show that the energy-dependence in the 100 TeV range of the correlation with temperature is sensitive to the fraction of muons and neutrinos from decay of charmed hadrons. We discuss the prospects for using the temperature effect as observed in gigaton neutrino detectors to measure the charm contribution.
We report the first observation of seasonal modulations in the rates of cosmic ray multiple-muon events at two underground sites, the MINOS Near Detector with an overburden of 225 mwe, and the MINOS Far Detector site at 2100 mwe. At the deeper site, multiple-muon events with muons separated by more than 8 m exhibit a seasonal rate that peaks during the summer, similar to that of single-muon events. In contrast and unexpectedly, the rate of multiple-muon events with muons separated by less than 5-8 m, and the rate of multiple-muon events in the smaller, shallower Near Detector, exhibit a season…
The Main Injector Neutrino Oscillation Search (MINOS) experiment's Far Detector has been operational since July 2003, taking cosmic ray and atmospheric neutrino data from its location in the Soudan Mine Underground Lab. Numerous neutrino-induced muons have been observed. The detector's magnetic field allows the first determination by a large underground detector of muon charge and thus neutrino versus anti-neutrino on an event by event basis.
We report the first direct observation of muon antineutrinos in the MINOS Far Detector in the current muon-neutrino dominated beam. The magnetic field of the detector is utilized to separate muon neutrinos and antineutrinos event-by-event by identifying the charge sign of the muon created in charged-current interactions. We present preliminary results on the muon antineutrino oscillation parameters as well as limit on the fraction of neutrinos that disappear and reappear as antineutrinos. We also discuss the prospect of the measurement when the polarity of the magnetic focusing horns will be r…
The magnetized MINOS Near Detector, at a depth of 225 meters of water equivalent (mwe), is used to measure the atmospheric muon charge ratio. The ratio of observed positive to negative atmospheric muon rates, using 301 days of data, is measured to be 1.266+/-0.001(stat.)+0.015/-0.014(syst.). This measurement is consistent with previous results from other shallow underground detectors, and is 0.108+/-0.019(stat. + syst.) lower than the measurement at the functionally identical MINOS Far Detector at a depth of 2070 mwe. This increase in charge ratio as a function of depth is consistent with an i…
Observed since the 1950's, the seasonal effect on underground muons is a well studied phenomenon. The interaction height of incident cosmic rays changes as the temperature of the atmosphere changes, which affects the production height of mesons (mostly pions and kaons). The decay of these mesons produces muons that can be detected underground. The production of muons is dominated by pion decay, and previous work did not include the effect of kaons. In this work, the methods of Barrett and MACRO are extended to include the effect of kaons. These efforts give rise to a new method to measure the …
A high significance observation of two muon signals, the shadow of the sun and moon, have been seen by the \unit[5.4]{kt} MINOS Far Detector, at a depth of \unit[2070]{mwe}. The distribution of angular separation of muons near the moon was well described by a Gaussian, which was used to determine the angular resolution ($0.34^{\circ}\pm0.07^{\circ}$) and pointing ($0.3^{\circ}\pm0.05^{\circ}$) of the detector.
The MINOS/MINOS+ experiment has recently reported stringent limits on $ν_μ$ disappearance that appear to rule out the 3+1 sterile neutrino model. However, in this paper we wish to point out problems associated with the MINOS/MINOS+ analysis. In particular, we find that MINOS/MINOS+ has either underestimated their systematic errors and/or has obtained evidence for physics beyond the 3-neutrino paradigm. Either case would invalidate the limits on $ν_μ$ disappearance.
The complete 5.4 kton MINOS far detector has been taking data since the beginning of August 2003 at a depth of 2070 meters water-equivalent in the Soudan mine, Minnesota. This paper presents the first MINOS observations of muon neutrino and muon anti-neutrino charged-current atmospheric neutrino interactions based on an exposure of 418 days. The ratio of upward to downward-going events in the data is compared to the Monte Carlo expectation in the absence of neutrino oscillations giving: R_data(up/down)/R_MC(up/down) = 0.62^{+0.19}_{-0.14} (stat.) +- 0.02 (sys.). An extended maximum likelihood …
The magnetized MINOS near detector can accurately determine the charge sign of atmospheric muons, this facilitates a measurement of the atmospheric muon charge ratio. To reduce the systematic error associated with geometric bias and acceptance we have combined equal periods of data obtained with opposite magnetic field polarities. We report a charge ratio of $1.2666\pm0.0015(stat.)^{+0.0096}_{-0.0088}(syst.)$ at a mean E$_{μ,0}cos(θ)$=\unit[63]{GeV}. This measurement is consistent with the world average\cite{Hebbeker}\cite{Haino}\cite{Achard} but significantly lower than the earlier observatio…
MINOS is the first large magnetic detector deep underground and is the first to measure the muon charge ratio with high statistics in the region near 1 TeV.\cite{bib:adamson} An approximate formula for the muon charge ratio can be expressed in terms of $ε_π$ = 115 GeV, $ε_K$ = 850 GeV and $\ec$. The implications for K production in the atmosphere will be discussed.
We found 140 neutrino-induced muons in 854.24 live days in the MINOS far detector. We looked for evidence of neutrino disappearance in this data set by computing the ratio of the number of low momentum muons to the sum of the number of high momentum and unknown momentum muons for both data and Monte Carlo expectation in the absence of neutrino oscillations. The ratio of data and Monte Carlo ratios is consistent with an oscillation signal. A fit to the data for the oscillation parameters excludes the null oscillation hypothesis at the 94% confidence level. We separated the muons by charge sign …
Borexino is an organic liquid scintillator detector located in the underground Gran Sasso National Laboratory (Italy). It is devoted mainly to the real time spectroscopy of low energy solar neutrinos via the elastic scattering on electrons in the target mass. The data taking campaign started in 2007 and led to key measurements of 7}Be and 8B solar neutrinos as well as antineutrinos from the earth (geo-neutrinos) and from nuclear power reactors. Borexino is also a powerful tool for the study of cosmic muons that penetrate the Gran Sasso rock coverage and thereby induced signals such as neutrons…
The 5.4 kton MINOS far detector has been taking charge-separated cosmic ray muon data since the beginning of August, 2003 at a depth of 2070 meters-water-equivalent in the Soudan Underground Laboratory, Minnesota, USA. The data with both forward and reversed magnetic field running configurations were combined to minimize systematic errors in the determination of the underground muon charge ratio. When averaged, two independent analyses find the charge ratio underground to be 1.374 +/- 0.004 (stat.) +0.012 -0.010(sys.). Using the map of the Soudan rock overburden, the muon momenta as measured u…
This letter reports results from the MINOS experiment based on its initial exposure to neutrinos from the Fermilab NuMI beam. The rate and energy spectra of charged current muon neutrino interactions are compared in two detectors located along the beam axis at distances of 1 km and 735 km. With 1.27 x 10^{20} 120 GeV protons incident on the NuMI target, 215 events with energies below 30 GeV are observed at the Far Detector, compared to an expectation of 336 \pm 14.4 events. The data are consistent with muon neutrino disappearance via oscillation with |Δm^2_{23}| = 2.74^{+0.44}_{-0.26} x 10^{-3…
This letter reports results from a search for muon-neutrino to electron-neutrino transitions by the MINOS experiment based on a 7x10^20 protons-on-target exposure. Our observation of 54 candidate electron-neutrino events in the Far Detector with a background of 49.1+/-7.0(stat.)+/-2.7(syst.) events predicted by the measurements in the Near Detector requires 2sin^2(2theta_{13})sin^2(theta_{23})<0.12 (0.20) at the 90% C.L. for the normal (inverted) mass hierarchy at delta_cp=0. The experiment sets the tightest limits to date on the value of theta_{13} for nearly all values of delta_cp for the no…
The observed neutrino flavor transitions are currently explained by the three flavor neutrino oscillation phenomenon, considered to be the leading order mechanism behind the flavor transitions. Currently existing data from LSND, MiniBooNE and reactor experiments demonstrate anomalies that could potentially be indications of non-standard neutrino phenomena. MINOS can probe transitions from muon neutrinos to electron neutrinos and search for anomalous behavior that cannot be explained by standard model neutrino oscillations. Here we present the search for second order effects in the flavor trans…
Production of high-energy muons in cosmic-ray air showers, relevant for underground detectors, depends on the properties of the primary cosmic ray as well as the atmospheric temperature through the competition between decay and re-interaction of charged pions and kaons. We present a parameterization of muon production profiles based on simulations as a function of the primary cosmic-ray energy, mass and zenith angle, the minimum energy for a muon to reach the detector and an atmospheric temperature profile. We illustrate how this can be used to calculate muon bundle properties such as multipli…
This letter reports on a search for $ν_μ\to ν_e$ transitions by the MINOS experiment based on a \unit[$3.14\times10^{20}$]{protons-on-target} exposure in the Fermilab NuMI beam. We observe 35 events in the Far Detector with a background of $27\pm 5 {\rm (stat.)} \pm 2 {\rm (syst.)$ events predicted by the measurements in the Near Detector. If interpreted in terms of $ν_μ\to ν_e$ oscillations, this 1.5 $σ$ excess of events is consistent with $\sin^{2}(2θ_{13})$ comparable to the CHOOZ limit when $|\delmsq{}|$=\unit[2.43$\times 10^{-3}$] {${\rm eV^{2}}$} and \sinsq{23}=1.0 are assumed.
The MINOS experiment at Fermilab has released an updated result on muon disappearance based upon 2.5 x 10^20 protons on target. The experiment utilizes the intense source of muon neutrinos provided by the NuMI beam line. This note summarizes the systematic uncertainties in the experiment's knowledge of the flux and energy spectrum of the neutrinos from NuMI.
Biases in the Determination of Correlations Between Underground Muon Flux and Atmospheric Temperature
School of Physics, Shandong University（山东大学物理学院）；Department of Physics and Astronomy, University of California, Irvine（加州大学尔湾分校物理与天文学系）；Jockey Club Institute for Advanced Study and Department of Physics, The Hong Kong University of Science and Technology（香港科技大学赛马会高级研究院及物理系）；Department of Physics, University of California, Berkeley（加州大学伯克利分校物理系）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；Faculty of Mathematics and Physics, Charles University（查理大学数学与物理学院）
The OPERA experiment discovered muon neutrino into tau neutrino oscillations in appearance mode, detecting tau leptons by means of nuclear emulsion films. The apparatus was also endowed with electronic detectors with tracking capability, such as scintillator strips and resistive plate chambers. Because of its location, in the underground Gran Sasso laboratory, under 3800 m.w.e., the OPERA detector has also been used as an observatory for TeV muons produced by cosmic rays in the atmosphere. In this paper the measurement of the single muon flux modulation and of its correlation with the seasonal…
The CoGeNT collaboration has recently published results from a fifteen month data set which indicate an annual modulation in the event rate similar to what is expected from weakly interacting massive particle interactions. It has been suggested that the CoGeNT modulation may actually be caused by other annually modulating phenomena, specifically the flux of atmospheric muons underground or the radon level in the laboratory. We have compared the phase of the CoGeNT data modulation to that of the concurrent atmospheric muon and radon data collected by the MINOS experiment which occupies an adjac…
Sources of seasonal temperature variations in the average energy of the muon flux detected in the LVD experiment have been discussed. It has been shown that variations are due to the processes of generation of muons in upper layers of the atmosphere and the passage of muons through a thick rock layer.
Updating our previous measurements with new data and analysis modifications, we report preliminary results on the energy-dependent deficit of muon neutrinos from the Fermilab NuMI beam as observed with the MINOS Far Detector located 735 km away in the Soudan Underground Laboratory. From an exposure of 2.50x10^20 protons on target, we observe 563 charged-current nu_mu interaction candidates in the Far Detector, where 738+/-30 events are expected in the absence of neutrino oscillations. We have analyzed these data assuming two-flavor nu_mu to nu_tau oscillations. From a simultaneous fit to the r…
MINOS will measure the composition of a neutrino beam at two locations, 735km apart, in an effort confirm the (atmospheric) neutrino oscillation hypothesis and measure the associated mixing parameters. Oscillations will be manifested as a difference in the rate and energy spectrum of muon neutrino CC interactions measured in the two detectors. Because most interactions observed in MINOS are inelastic, the neutrino energy is reconstructed as the sum of the energy carried by the muon and that seen in the hadronic shower emanating from the struck nucleus. The latter is sensitive to uncertainties …
In the past years, large particle-physics experiments have shown that muon rate variations detected in underground laboratories are sensitive to regional, middle-atmosphere temperature variations. Potential applications include tracking short-term atmosphere dynamics, such as Sudden Stratospheric Warmings. We report here that such sensitivity is not only limited to large surface detectors under high-opacity conditions. We use a portable muon detector conceived for muon tomography for geophysical applications and we study muon rate variations observed over one year of measurements at the Mont T…
A sample of 1.53$\times$10$^{9}$ cosmic-ray-induced single muon events has been recorded at 225 meters-water-equivalent using the MINOS Near Detector. The underground muon rate is observed to be highly correlated with the effective atmospheric temperature. The coefficient $α_{T}$, relating the change in the muon rate to the change in the vertical effective temperature, is determined to be 0.428$\pm$0.003(stat.)$\pm$0.059(syst.). An alternative description is provided by the weighted effective temperature, introduced to account for the differences in the temperature profile and muon flux as a f…
The MINOS Near and Far Detectors are two large, functionally-identical, steel-scintillating sampling calorimeters located at depths of 220 mwe and 2100 mwe respectively. The detectors observe the muon component of hadronic showers produced from cosmic ray interactions with nuclei in the earth's atmosphere. From the arrival direction of these muons, the anisotropy in arrival direction of the cosmic ray primaries can be determined. The MINOS Near and Far Detector have observed anisotropy on the order of 0.1% at 1 and 11 TeV respectively. The amplitude and phase of the first harmonic at 1 TeV are…
Data from the MINOS experiment has been used to search for mixing between muon neutrinos and muon antineutrinos using a time-independent Lorentz-violating formalism derived from the Standard-Model Extension (SME). MINOS is uniquely capable of searching for muon neutrino-antineutrino mixing given its long baseline and ability to distinguish between neutrinos and antineutrinos on an event-by-event basis. Neutrino and antineutrino interactions were observed in the MINOS Near and Far Detectors from an exposure of 10.56$\times10^{20}$ protons-on-target from the NuMI neutrino-optimized beam. No evid…
We report an improved measurement of muon anti-neutrino disappearance over a distance of 735km using the MINOS detectors and the Fermilab Main Injector neutrino beam in a muon anti-neutrino enhanced configuration. From a total exposure of 2.95e20 protons on target, of which 42% have not been previously analyzed, we make the most precise measurement of the anti-neutrino "atmospheric" delta-m squared = 2.62 +0.31/-0.28 (stat.) +/- 0.09 (syst.) and constrain the anti-neutrino atmospheric mixing angle >0.75 (90%CL). These values are in agreement with those measured for muon neutrinos, removing the…
We report the first detailed comparisons of the rates and spectra of neutral-current neutrino interactions at two widely separated locations. A depletion in the rate at the far site would indicate mixing between muon neutirnos and a sterile particle. No anomalous depletion in the reconstructed energy spectrum is observed. Assuming oscillations occur at a single mass-squared splitting, a fit to the neutral- and charged-current energy spectra limits the fraction of muon neutrino oscillating to a sterile neutrino to be below 0.68 at 90% confidence level. A less stringent limit due to a possible c…
A search for disappearance of active neutrinos over a baseline of 735 km was conducted using the NuMI neutrino beam and the MINOS detectors. The data analyzed correspond to an exposure of 3.18x10^{20} protons on target. The data are fitted to neutrino oscillation models in which mixing with one sterile neutrino is assumed. A comparison of the neutral-current-like spectrum at the FD with the expectation derived from the near detector measurement shows that the fraction of disappearing muon neutrinos converting to a sterile state is less than 52% at the 90% confidence level. In addition, the pos…
We report the rate of cosmic ray air showers with multiplicities exceeding 15 muon tracks recorded in the NOvA Far Detector between May 2016 and May 2018. The detector is located on the surface under an overburden of 3.6 meters water equivalent. We observe a seasonal dependence in the rate of multiple-muon showers, which varies in magnitude with multiplicity and zenith angle. During this period, the effective atmospheric temperature and surface pressure ranged between 210 K to 230 K and 940mbar to 990mbar, respectively; the shower rates are anti-correlated with the variation in the effective t…
The charge ratio, $R_μ= N_{μ^+}/N_{μ^-}$, for cosmogenic multiple-muon events observed at an under- ground depth of 2070 mwe has been measured using the magnetized MINOS Far Detector. The multiple-muon events, recorded nearly continuously from August 2003 until April 2012, comprise two independent data sets imaged with opposite magnetic field polarities, the comparison of which allows the systematic uncertainties of the measurement to be minimized. The multiple-muon charge ratio is determined to be $R_μ= 1.104 \pm 0.006 {\rm \,(stat.)} ^{+0.009}_{-0.010} {\rm \,(syst.)} $. This measurement com…
The Main Injector Neutrino Oscillation search (MINOS) uses two detectors separated by 735km to measure a beam of neutrinos created by the Neutrinos at the Main Injector (NuMI) facility at Fermi National Accelerator Laboratory. The experiment has recently reported an observation of muon-neutrino disappearance consistent with neutrino oscillations. We describe the manner in which the experiment's results depend on the correct understanding and modeling of hadronic systems.
We have searched for sidereal variations in the rate of antineutrino interactions in the MINOS Near Detector. Using antineutrinos produced by the NuMI beam, we find no statistically significant sidereal modulation in the rate. When this result is placed in the context of the Standard Model Extension theory we are able to place upper limits on the coefficients defining the theory. These limits are used in combination with the results from an earlier analysis of MINOS neutrino data to further constrain the coefficients.
We propose a test to compare the speed of muons and muon neutrinos produced in the same bundles in the atmosphere. By comparing the arrival times of primary muons and muons induced by neutrinos, experiments such as Super-Kamiokande, IceCube and ANTARES could verify recent hints on the possibility that neutrinos have a velocity larger than the speed of light. For smaller detectors such as MINOS and OPERA, where it may be challenging to recognize downgoing muons induced by neutrinos inside the active volume, another measurement may be possible thanks to the ns-time resolution. The arrival times …
The shadowing of cosmic ray primaries by the the moon and sun was observed by the MINOS far detector at a depth of \unit[2070]{mwe} using 83.54 million cosmic ray muons accumulated over 1857.91 live-days. The shadow of the moon was detected at the \unit[5.6]{$σ$} level and the shadow of the sun at the \unit[3.8]{$σ$} level using a log-likelihood search in celestial coordinates. The moon shadow was used to quantify the absolute astrophysical pointing of the detector to be 0.17\pm 0.12^\circ. Hints of Interplanetary Magnetic Field effects were observed in both the sun and moon shadow.
ArgoNeuT, or Argon Neutrino Test, is a 170 liter liquid argon time projection chamber designed to collect neutrino interactions from the NuMI beam at Fermi National Accelerator Laboratory. ArgoNeuT operated in the NuMI low-energy beam line directly upstream of the MINOS Near Detector from September 2009 to February 2010, during which thousands of neutrino and antineutrino events were collected. The MINOS Near Detector was used to measure muons downstream of ArgoNeuT. Though ArgoNeuT is primarily an R&D project, the data collected provide a unique opportunity to measure neutrino cross sections …
This letter reports new results from the MINOS experiment based on a two-year exposure to muon neutrinos from the Fermilab NuMI beam. Our data are consistent with quantum mechanical oscillations of neutrino flavor with mass splitting $|Δm^2|=(2.43\pm 0.13)\times10^{-3}$ eV$^2$ (68% confidence level) and mixing angle $\sin^2(2θ)>0.90$ (90% confidence level). Our data disfavor two alternative explanations for the disappearance of neutrinos in flight, namely neutrino decays into lighter particles and quantum decoherence of neutrinos, at the 3.7 and 5.7 standard deviation levels, respectively.
We report the results of a search for $ν_{e}$ appearance in a $ν_μ$ beam in the MINOS long-baseline neutrino experiment. With an improved analysis and an increased exposure of $8.2\times10^{20}$ protons on the NuMI target at Fermilab, we find that $2\sin^2(θ_{23})\sin^2(2θ_{13})<0.12\ (0.20)$ at 90% confidence level for $δ\mathord{=}0$ and the normal (inverted) neutrino mass hierarchy, with a best fit of $2\sin^2(θ_{23})\sin^2(2θ_{13})\,\mathord{=}\,0.041^{+0.047}_{-0.031}\ (0.079^{+0.071}_{-0.053})$. The $θ_{13}\mathord{=}0$ hypothesis is disfavored by the MINOS data at the 89% confidence lev…
The Daya Bay Experiment consists of eight identically designed detectors located in three underground experimental halls named as EH1, EH2, EH3, with 250, 265 and 860 meters of water equivalent vertical overburden, respectively. Cosmic muon events have been recorded over a two-year period. The underground muon rate is observed to be positively correlated with the effective atmospheric temperature and to follow a seasonal modulation pattern. The correlation coefficient $α$, describing how a variation in the muon rate relates to a variation in the effective atmospheric temperature, is found to b…
The MINOS experiment has observed a rise in the underground muon charge ratio $r_μ$ = ${μ^+/μ^-}$. This ratio can be related to the atmospheric production ratios of ${π^+/π^-}$ and ${K^+/K^-}$. Our analysis indicates that the relevant variable for studying the charge ratio+ $\ecos$, rather than $\emu$. We compare a simple energy dependent parameterization of the rise in the charge ratio with more detailed previously published Monte Carlo simulations and an analytical calculation. We also estimate the size of two previously neglected effects in this context: the charge sign dependency of the dE…
The MINOS experiment took data from 2005 up until 2012. This was superseded by MINOS+, the continuation of the two-detector, on-axis, long-baseline experiment based at Fermilab, and at the Soudan Underground Laboratory in northern Minnesota. By searching for the deficit of muon neutrinos at the Far Detector, MINOS/MINOS+ is sensitive to the atmospheric neutrino oscillation parameters $Δm^{2}_{32}$ and $θ_{23}$. By using the full MINOS data set looking at both \numu disappearance and \nue appearance in both neutrino and anti-neutrino configurations at the NuMI beam along with atmospheric neutri…
A search for mixing between active neutrinos and light sterile neutrinos has been performed by looking for muon neutrino disappearance in two detectors at baselines of 1.04 km and 735 km, using a combined MINOS and MINOS+ exposure of $16.36\times10^{20}$ protons-on-target. A simultaneous fit to the charged-current muon neutrino and neutral-current neutrino energy spectra in the two detectors yields no evidence for sterile neutrino mixing using a 3+1 model. The most stringent limit to date is set on the mixing parameter $\sin^2θ_{24}$ for most values of the sterile neutrino mass-splitting $Δm^2…
A Neutrino Factory producing an intense beam composed of nu_e(nubar_e) and nubar_mu(nu_mu) from muon decays has been shown to have the greatest sensitivity to the two currently unmeasured neutrino mixing parameters, theta_13 and delta_CP . Using the `wrong-sign muon' signal to measure nu_e to nu_mu(nubar_e to nubar_mu) oscillations in a 50 ktonne Magnetised Iron Neutrino Detector (MIND) sensitivity to delta_CP could be maintained down to small values of theta_13. However, the detector efficiencies used in previous studies were calculated assuming perfect pattern recognition. In this paper, MIN…
MINOS searches for neutrino oscillations using the disappearance of muon neutrinos between two detectors, over a baseline of 735 km. We recently reported the most precise measurement of neutrino oscillations in the atmospheric sector and the first tagged measurement of antineutrino oscillations. The neutrino mass splitting and mixing angle are measured to be $|Δm^{2}| = 2.32_{-0.08}^{+0.12} \times 10^{-3}\,eV^{2}$ and $\sin^{2}2θ> 0.90$ (90% C.L.) for an exposure of $7.25 \times 10^{20}$ protons-on-target (PoT). Antineutrino oscillation parameters are measured as $Δ\bar{m}^{2}=(3.36^{+0.46}_{-…
We have measured the flux of cosmic muons in the Laboratori Nazionali del Gran Sasso at 3800\,m\,w.e. to be $(3.432 \pm 0.003)\cdot 10^{-4}\,\mathrm{{m^{-2}s^{-1}}}$ based on ten years of Borexino data acquired between May 2007 and May 2017. A seasonal modulation with a period of $(366.3 \pm 0.6)\,\mathrm{d}$ and a relative amplitude of $(1.36 \pm0.04)\%$ is observed. The phase is measured to be $(181.7 \pm 0.4)\,\mathrm{d}$, corresponding to a maximum at the 1$^\mathrm{st}$ of July. Using data inferred from global atmospheric models, we show the muon flux to be positively correlated with the …
This letter reports the first direct observation of muon antineutrino disappearance. The MINOS experiment has taken data with an accelerator beam optimized for muon antineutrino production, accumulating an exposure of $1.71\times 10^{20}$ protons on target. In the Far Detector, 97 charged current muon antineutrino events are observed. The no-oscillation hypothesis predicts 156 events and is excluded at $6.3σ$. The best fit to oscillation yields $Δ\bar{m}^{2}=(3.36^{+0.46}_{-0.40}\textrm{(stat.)}\pm0.06\textrm{(syst.)})\times 10^{-3}\,\eV^{2}$, $\sin^{2}(2\barθ)=0.86^{+0.11}_{-0.12}\textrm{(sta…
We report a measurement of muon annual modulation in a 12-liter liquid scintillation detector with a live-time of more than 4 years at the Soudan Underground Laboratory. Muon minimum ionization in the detector is identified by its observed pulse shape and large energy deposition. The measured muon rate in the detector is 28.69$\pm$2.09 muons per day with a modulation amplitude of 2.66$\pm$ 1.0\% and a phase at Jul 22 $\pm$ 36.2 days. This annual modulation is correlated with the variation of the effective atmospheric temperature in the stratosphere. The correlation coefficient, $α_{T}$, is det…
We report results of a search for oscillations involving a light sterile neutrino over distances of 1.04 and $735\,\mathrm{km}$ in a $ν_μ$-dominated beam with a peak energy of $3\,\mathrm{GeV}$. The data, from an exposure of $10.56\times 10^{20}\,\textrm{protons on target}$, are analyzed using a phenomenological model with one sterile neutrino. We constrain the mixing parameters $θ_{24}$ and $Δm^{2}_{41}$ and set limits on parameters of the four-dimensional Pontecorvo-Maki-Nakagawa-Sakata matrix, $|U_{μ4}|^{2}$ and $|U_{τ4}|^{2}$, under the assumption that mixing between $ν_{e}$ and $ν_{s}$ is…
This paper reports measurements of atmospheric neutrino and antineutrino interactions in the MINOS Far Detector, based on 2553 live-days (37.9 kton-years) of data. A total of 2072 candidate events are observed. These are separated into 905 contained-vertex muons and 466 neutrino-induced rock-muons, both produced by charged-current $ν_μ$ and $\barν_μ$ interactions, and 701 contained-vertex showers, composed mainly of charged-current $ν_{e}$ and $\barν_{e}$ interactions and neutral-current interactions. The curvature of muon tracks in the magnetic field of the MINOS Far Detector is used to selec…
The SuperKamiokande atmospheric neutrino measurements leave substantial room for nonstandard interactions (NSI) of neutrinos with matter in the nu_e- nu_tau sector. Large values of the NSI couplings are accommodated if the vacuum oscillation parameters are changed from their standard values. Short and medium baseline neutrino beams can break this degeneracy by measuring the true vacuum oscillation parameters with the muon neutrino disappearance mode, for which the matter effects are negligible or subdominant. These experiments can also search for the nu_e-nu_tau flavor changing effects directl…
Multiplexed SiPM Readout of Plastic Scintillating Fiber Detector for Muon Tomography
Institute for Advanced Technology, Shandong University（山东大学前沿技术研究院）；Particle Physics Research Center, Shandong Institute of Advanced Technology（山东大学前沿技术研究院粒子物理研究中心）
