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| '''Measurements of neutrino speed''' have been conducted as [[tests of special relativity]] and for the determination of the [[mass]] of [[neutrino]]s. Astronomical searches investigate whether light and neutrinos emitted simultaneously from a distant source are arriving simultaneously on Earth. Terrestrial searches include [[time of flight]] measurements using synchronized clocks, and direct comparison of neutrino speed with the speed of other particles.
| | Different people have different goals in mind when working on their home. Some are tired of the old look. Other [http://data.gov.uk/data/search?q=people+seek people seek] to raise the value of their home through improvements. While still others do it simply because they enjoy working with their hands. Whatever your motivation is, these tips will put you on the right path.<br><br>If you have a large garden but would like more indoor living space, adding a conservatory is one home improvement you should consider. A conservatory will provide an additional room to your house that will be filled with natural light. The room can be used for moonlit dinners, home gym equipment, sun lounges and much more. The structure is also likely to catch the eye of potential buyers and increase the resale value of your home.<br><br>If you have a cabinet door that just won't stay closed, try replacing the cabinet lock. You might want to try using a magnetic cabinet lock, as they generally last longer than wheel based cabinet lock systems. Simply remove the old lock and attach the new lock in the same location. Use wood screws if needed to create new holes.<br><br>Even DIY home improvement enthusiasts with little experience can repair faucet leaks. You can cut down on water waste and usage by repairing your faucets quickly. The savings alone will add up quite nicely if you tackle this problem right away.<br><br>Before you start painting a room, it is best to know about how much paint you need. Measure the length of the walls in the room you plan to paint and add them together. Next, measure the height of the room. Multiply the height by the length. The square foot of the room is the answer you get. One gallon of paint will generally cover 350 square feet.<br><br>Take your trash out at least once a day. Don't let your trash pile in the kitchen because it attracts flies and ants as well as mold. Make sure that you don't let your trash take over your kitchen and set aside three minutes a day when you throw it out.<br><br>Increase your home's value by refinishing your floors. Re-finishing floors is a big job, but it is not a very difficult one. You can take classes that can help you at your local home store. Doing the work yourself can save lots of money.<br><br>If you're looking to add variety to your rooms with paint you can do it very quickly and cost effectively. Paint one wall a different striking color in your room that doesn't match the other wall colors. This will create a new focal point in your room and make your space feel like it just had a real update.<br><br>You should always purchase the materials you need for home improvement projects in the largest possible lots. Building materials have some of the deepest volume discounts you will ever see. By planning ahead you can figure out how much material you are likely to need and buy it all at once. This will cost you much less than making multiple purchases.<br><br>A great home improvement tip is to not let your ego get in the way when making renovations. Sometimes, a renovation you may have in mind does not need to be done because it could violate a particular building code, or it could even harm the value of your home.<br><br>When you are designing your kitchen, think hard about whether you want an open or closed kitchen floor plan. If you like to be able to talk with your family, watch television and generally know what's going on in the rest of the house while cooking, you may want an open kitchen plan. However, if you would prefer for the kitchen clutter to stay hidden, you may prefer a kitchen with a door that can be closed.<br><br>Kitchen cabinets can be extremely heavy. Make them lighter by removing the doors and drawers from all of your new cabinets before installing them. The lighter cabinets will be easier to maneuver and there will be nothing to get in your way as you screw the cabinets to the wall.<br><br>A deck can be a great addition to your home, but you need to be on the lookout for the common telltale signs that indicate your deck is due for [http://answers.yahoo.com/search/search_result?p=maintenance&submit-go=Search+Y!+Answers maintenance]. You may find uneven boards, cracks in wood or handrails or even dry rot. Take a closer look to find nails and screws that need replacing.<br><br>Your home is one of your most valuable financial assets, and it is the place where you spend a majority of your time. So the next time you spot something that could use a little maintenance, you owe it to yourself, and to your wallet, to try your hand at fixing up your home!<br><br>Here's more about [http://oafishintrospec17.jimdo.com perth commercial roofing] take a look at our web site. |
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| Since it is established that neutrinos possess mass, the speed of neutrinos should be slightly smaller than the [[speed of light]] in accordance with [[special relativity]]. Existing measurements provided upper limits for deviations of approximately 10<sup>−9</sup>, or a [[Parts-per notation|few parts per billion]]. Within the [[margin of error]] this is consistent with no deviation at all.
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| == Overview ==
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| [[File:RelNeutrinoSpeed.svg|thumb|350px|Neutrino speed as a function of relativistic [[kinetic energy]], with neutrino mass < 0.2 eV/c².
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| {| class=wikitable style="text-align:center"
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| |style="border-right:2px solid black"| '''Energy'''||10 eV||1 KeV||1 MeV||1 GeV||1 TeV
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| |-
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| |style="border-right:2px solid black; padding-right:10px;"| <math>|v-c|/c</math>||<math>\scriptstyle \lesssim10^{-4}</math>||<math>\scriptstyle\lesssim10^{-8}</math>||<math>\scriptstyle\lesssim10^{-14}</math>||<math>\scriptstyle\lesssim10^{-20}</math>||<math>\scriptstyle\lesssim10^{-26}</math>
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| |}]]
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| It was assumed for a long time in the framework of the [[standard model]] of [[particle physics]], that [[neutrino]]s are massless. Thus they should travel at exactly the speed of light according to special relativity. However, since the discovery of [[neutrino oscillation]]s it is assumed that they are massive.<ref>{{cite journal |author=J. Beringer et al. ([[Particle Data Group]]) |year=2012 |title=Neutrino Properties - Review of Particle Physics |journal=Physical Review D |volume=86 |issue=1 |page=010001 |doi=10.1103/PhysRevD.86.010001|url=http://pdg.lbl.gov/2013/listings/contents_listings.html|bibcode = 2012PhRvD..86a0001B }}</ref> Thus they should travel slightly slower than the speed of light, otherwise their [[Tests of relativistic energy and momentum|relativistic energy]] would become infinitely large. This energy is given by
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| :<math>E=\frac{mc^{2}}{\sqrt{1-\frac{v^{2}}{c^{2}}}}</math>,
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| ''v'' being the neutrino speed and ''c'' the speed of light. The neutrino mass ''m'' is currently estimated as being 2 [[electronvolt|eV]]/c², and is possibly even lower than 0.2 eV/c². According to the latter mass value and the formula for relativistic energy, relative speed differences between light and neutrinos are smaller at high energies, and should arise as indicated in the figure on the right.
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| Time-of-flight measurements conducted so far investigated neutrinos of energy above 10 MeV. However, velocity differences predicted by relativity at such high energies cannot be determined with the current precision of time measurement. The reason why such measurements are still conducted, is connected with the theoretical possibility that significantly larger deviations from light speed might arise under certain circumstances. For instance, it was postulated that neutrinos might be some sort of [[faster-than-light|superluminal]] particles called [[tachyon]]s,<ref>{{cite journal |author=Chodos, Alan; Hauser, Avi I.; Alan Kostelecký, V. |year=1985 |title=The Neutrino as a Tachyon |journal=Physics Letters B |volume=150 |issue=6 |page=431 |doi= 10.1016/0370-2693(85)90460-5|bibcode = 1985PhLB..150..431C }}</ref> even though others criticized this proposal.<ref>{{cite journal | author=Hughes, Richard J.; Stephenson, G. J. |year=1990 |title=Against tachyonic neutrinos |journal=Physics Letters B |volume=244 |issue=1 |pages=95–100 |doi=10.1016/0370-2693(90)90275-B|bibcode = 1990PhLB..244...95H }}</ref> While hypothetical tachyons are thought to be compatible with [[Lorentz invariance]], superluminal neutrinos have also been studied in Lorentz invariance violating frameworks as motivated by speculative variants of [[quantum gravity]], such as the [[Standard-Model Extension]] according to which [[Lorentz-violating neutrino oscillations]] can arise.<ref name=diaz>{{cite journal |author=Díaz, Jorge S.; Kostelecký, V. Alan|title=Lorentz- and CPT-violating models for neutrino oscillations|journal=Physical Review D|volume=85|issue=1 |year=2012|doi=10.1103/PhysRevD.85.016013|pages=016013|arxiv=1108.1799|bibcode = 2012PhRvD..85a6013D }}</ref> Besides time-of-flight measurements, those models also allow for [[#Indirect determinations of neutrino speed|indirect determinations of neutrino speed]] and other [[modern searches for Lorentz violation]]. All of those experiments confirmed Lorentz invariance and special relativity.
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| == Fermilab (1970s) ==
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| [[Fermi National Accelerator Laboratory|Fermilab]] conducted in the 1970s a series of terrestrial measurements, in which the speed of [[muon]]s was compared with that of neutrinos and antineutrinos of energies between 30 and 200 GeV. The Fermilab narrow band neutrino beam was generated as follows: 400-GeV [[proton]]s are hitting the target and causing the production of secondary beams consisting of [[pion]]s and [[kaon]]s. Then they are decaying in an evacuated decay tube of 235 meter length. The remaining [[hadron]]s were stopped by a secondary dump, so that only neutrinos and some energetic muons can penetrate the earth- and steel shield of 500 meter length, in order to reach the [[particle detector]].
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| Since the protons are transferred in bunches of one [[nanosecond]] duration at an interval of 18.73 ns, the speed of muons and neutrinos could be determined. A speed difference would lead to an elongation of the neutrino bunches and to a displacement of the whole neutrino time spectrum. At first, the speeds of muons and neutrinos were compared.<ref>{{cite journal |author=P. Alspector ''et al.'' |title=Experimental Comparison of Neutrino and Muon Velocities |volume=36 |issue=15| year=1976 |journal=Physical Review Letters|doi=10.1103/PhysRevLett.36.837|pages=837–840|bibcode = 1976PhRvL..36..837A}}</ref>
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| Later, also antineutrinos were observed.<ref>{{cite journal |author=Kalbfleisch et al.|title=Experimental Comparison of Neutrino, Antineutrino, and Muon Velocities |volume=43 |issue=19| year=1979 |journal=Physical Review Letters|doi=10.1103/PhysRevLett.43.1361|pages=1361–1364|bibcode = 1979PhRvL..43.1361K |last2=Baggett |first2=Neil |last3=Fowler |first3=Earle |last4=Alspector |first4=Joshua }}</ref>
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| The upper limit for deviations from light speed was: | |
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| :<math>\frac{|v-c|}{c}<4\times10^{-5}</math>.
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| This was in agreement with the speed of light within the measurement accuracy (95% [[confidence level]]), and also no energy dependence of neutrino speeds could be found at this accuracy.
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| == Supernova 1987A ==
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| The most precise agreement with the speed of light ({{As of|2012|lc=on}}) was determined in 1987 by the observation of electron antineutrinos of energies between 7.5 and 35 MeV originated at the [[Supernova 1987A]] at a distance of 157000 ± 16000 [[light year]]s. The upper limit for deviations from light speed was:
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| :<math>\frac{|v-c|}{c}<2\times10^{-9}</math>,
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| thus 1.000000002 times the speed of light. This value was obtained by comparing the arrival times of light and neutrinos. The difference of approximately three hours was explained by the circumstance, that the almost noninteracting neutrinos could pass the supernova unhindered while light required a longer time.<ref>{{cite journal |author=Hirata, ''et al.''|year=1987 |volume=58 |title=Observation of a neutrino burst from the supernova SN1987A|journal=Physical Review Letters|doi=10.1103/PhysRevLett.58.1490|pages=1490–1493|bibcode = 1987PhRvL..58.1490H |issue=14 |pmid=10034450 }}</ref><ref>{{cite journal |author=Bionta, ''et al.''|year=1987 |volume=58 |title=Observation of a neutrino burst in coincidence with supernova 1987A in the Large Magellanic Cloud|journal=Physical Review Letters|doi=10.1103/PhysRevLett.58.1494|pages=1494–1496|bibcode = 1987PhRvL..58.1494B |issue=14 |pmid=10034451 }}</ref><ref>{{cite journal |author=Longo, Michael J.|title=Tests of relativity from SN1987A|journal=Physical Review D|volume=236|issue=10|year=1987 |pages=3276–3277|doi=10.1103/PhysRevD.36.3276|bibcode = 1987PhRvD..36.3276L }}</ref><ref>{{cite journal |author=Stodolsky, Leo|title=The speed of light and the speed of neutrinos|journal=Physics Letters B|volume=201|issue=3|year=1988 |pages=353–354|doi=10.1016/0370-2693(88)91154-9|bibcode = 1988PhLB..201..353S }}</ref>
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| == MINOS (2007) ==
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| The first terrestrial measurement of the absolute transit time was conducted by [[MINOS]] (2007) at Fermilab. In order to generate neutrinos (the so-called [[NuMI]] beam) they used the Fermilab Main Injector, by which 120-GeV-protons were directed to a [[graphite]] target in 5 to 6 batches per spill. The emerging [[meson]]s decayed in a 675 meter long decay tunnel into muon neutrinos (93%) and muon antineutrinos (6%). The travel time was determined by comparing the arrival times at the MINOS near- and far detector, apart from each other by 734 km. The clocks of both stations were synchronized by [[GPS]], and long [[optical fiber]]s were used for signal transmission.<ref name=minos>{{cite journal |author=MINOS collaboration |year=2007 |issue=7 |title=Measurement of neutrino velocity with the MINOS detectors and NuMI neutrino beam |volume=76 | first1= |journal=[[Physical Review D]] |arxiv=0706.0437 |bibcode=2007PhRvD..76g2005A|doi=10.1103/PhysRevD.76.072005}}</ref>
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| They measured an early neutrino arrival of approximately 126 ns. Thus the relative speed difference was <math>\scriptstyle (5.1\pm2.9)\times10^{-5}</math> (68% confidence limit). This corresponds to 1.000051±29 times the speed of light, thus apparently faster than light. The major source of error were uncertainties in the fiber optic delays. The statistical significance of this result was less than 1.8[[standard deviations|σ]], thus it was not significant since 5σ is required to be accepted as a scientific discovery.
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| At 99% confidence level it was given<ref name=minos />
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| :<math>-2.4\times10^{-5}<\frac{v-c}{c}<12.6\times10^{-5}</math>,
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| a neutrino speed larger than 0.999976c and lower than 1.000126c. Thus the result is also compatible with subluminal speeds.
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| == OPERA (2011, 2012) ==
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| === Anomaly ===
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| {{Main|Faster-than-light neutrino anomaly}}
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| In the [[OPERA experiment]], 17-GeV neutrinos have been used, split in proton extractions of 10,5 µs length generated at [[CERN]], which hit a target at a distance of 743 km. Then pions and kaons are produced which partially decayed into muons and muon neutrinos ([[CERN Neutrinos to Gran Sasso]], CNGS). The neutrinos traveled further to the [[Laboratori Nazionali del Gran Sasso]] (LNGS) 730 km away, where the OPERA detector is located. GPS was used to synchronize the clocks and to determine the exact distance. In addition, optical fibers were used for signal transmission at LNGS. The temporal distribution of the proton extractions was statistically compared with approximately 16000 neutrino events. OPERA measured an early neutrinos arrival of approximately 60 nanoseconds, as compared to the expected arrival at the speed of light, thus indicating a neutrino speed faster than that of light. Contrary to the MINOS result, the deviation was 6σ and thus apparently significant.<ref>{{cite arxiv|author=OPERA collaboration|title=Measurement of the neutrino velocity with the OPERA detector in the CNGS beam|eprint=1109.4897|version=v1|date=22 September 2011|class=hep-ex}}</ref><ref>{{cite web|author=Giulia Brunetti|title=Neutrino velocity measurement with the OPERA experiment in the CNGS beam|url=http://operaweb.lngs.infn.it:2080/Opera/ptb/theses/theses/Brunetti-Giulia_phdthesis.pdf|publisher=Dissertation|year=2011|accessdate=24 November 2011}}</ref><ref name=PrRel>{{cite web|title=OPERA experiment reports anomaly in flight time of neutrinos from CERN to Gran Sasso|publisher=CERN press release|url=http://press.web.cern.ch/Press/PressReleases/Releases2011/PR19.11E.html|date=23 February 2012|accessdate=23 February 2012}}</ref>
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| To exclude possible statistical errors, CERN produced bunched proton beams between October and November 2011. The proton extractions were split into short bunches of 3 ns at intervals of 524 ns, so that every neutrino event could be directly connected to a proton bunch. The measurement of twenty neutrino events again gave an early arrival of about 62 ns, in agreement with the previous result. They updated their analysis and increased the significance up to 6,2σ.<ref>{{cite arxiv|author=OPERA collaboration|title=Measurement of the neutrino velocity with the OPERA detector in the CNGS beam|eprint=1109.4897|version=v2|date=18 November 2011|class=hep-ex}}</ref><ref>{{cite web|title=New Tests Confirm The Results Of OPERA On The Neutrino Velocity, But It Is Not Yet The Final Confirmation|publisher=INFN press release|url=http://www.interactions.org/cms/?pid=1031226|date=18 November 2011|accessdate=18 November 2011}}</ref>
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| In February and March 2012, it was shown that there were two mistakes in the experimental equipment: An erroneous cable connection at a computer card, making the neutrinos appearing faster than expected. The other one was an oscillator out of its specification, making the neutrinos appearing slower than expected. Then the time of arrival of cosmic high-energy muons at OPERA and the co-located LVD detector between 2007–2008, 2008–2011, and 2011–2012 were compared. It was found out that between 2008–2011, the cable connector error caused a deviation of approximately 73 ns, and the oscillator error caused ca. 15 ns in the opposite direction.<ref name=seminar>LNGS seminar (28 March 2012): [http://agenda.infn.it/materialDisplay.py?materialId=slides&confId=4896 LNGS results on the neutrino velocity topic]</ref><ref>{{cite journal |author=LVD and OPERA collaboration|title=Determination of a time-shift in the OPERA set-up using high energy horizontal muons in the LVD and OPERA detectors|journal=The European Physical Journal Plus|volume=127|issue=6|year=2012|pages=71|doi=10.1140/epjp/i2012-12071-5|arxiv=1206.2488|bibcode = 2012EPJP..127...71A }}.</ref>
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| This and the measurement of neutrino velocities consistent with the speed of light by the ICARUS collaboration (see [[#ICARUS (2012)|ICARUS (2012)]]), indicated that the neutrinos were actually not faster than light.<ref name=cernfinal>{{cite web|title=Neutrinos sent from CERN to Gran Sasso respect the cosmic speed limit|publisher=CERN press release|url=http://press.web.cern.ch/Press/PressReleases/Releases2011/PR19.11E.html|date=8 June 2012|accessdate=8 June 2012}}</ref> | |
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| === End result ===
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| Finally, in July 2012 the OPERA collaboration published a new analysis of their data from 2009–2011, which included the instrumental effects stated above, and obtained bounds for arrival time differences (compared to the speed of light):
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| :<math>\delta t=6.5\pm7.4\ (\mathrm{stat.}){\scriptstyle {+8.3\atop -8.0}}\ (\mathrm{sys.})</math> nanoseconds,
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| and bounds for speed differences:
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| :<math>\frac{v-c}{c}=(2.7\pm3.1\ (\mathrm{stat.}){\scriptstyle {+3.4\atop -3.3}}\ (\mathrm{sys.}))\times10^{-6}</math>.
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| Also the corresponding new analysis for the bunched beam of October and November 2011 agreed with this result:
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| :<math>\delta t=-1.9\pm3.7\ (\mathrm{stat.})</math> nanoseconds
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| All of those results are consistent with the speed of light, and the <math>10^{-6}</math> bound for the speed difference is more precise by one order of magnitude than previous terrestrial time-of-flight measurements.<ref>{{cite journal|author=OPERA collaboration|title=Measurement of the neutrino velocity with the OPERA detector in the CNGS beam|journal=Journal of High Energy Physics|issue=10|pages=93|year=2012|arxiv=1109.4897v4|doi=10.1007/JHEP10(2012)093|volume=2012|bibcode = 2012JHEP...10..093A }}</ref>
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| == ICARUS (2012) ==
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| Already before the OPERA collaboration updated their result, the [[ICARUS (experiment)|ICARUS]] collaboration published measurements of neutrino velocity in March 2012. The ICARUS detector is also located at LNGS, and is receiving CNGS neutrinos from CERN. Simultaneously with OPERA (and using some of the LNGS equipment that was also used by OPERA), they tried to capture neutrino events produced at the bunched beam rerun from October to November 2011. They observed seven neutrino events and found the following arrival time compared to the expected arrival time at the speed of light:<ref>{{Cite journal|author=ICARUS collaboration|title=Measurement of the neutrino velocity with the ICARUS detector at the CNGS beam|journal=Physics Letters B|volume=713|issue=1|pages=17–22|doi=10.1016/j.physletb.2012.05.033|arxiv=1203.3433|year=2012|bibcode = 2012PhLB..713...17I }}</ref>
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| :<math>\delta t=0.3\pm4.0_{stat.}\pm9.0_{sys.}</math> nanoseconds.
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| This means that no difference exists between the speed of neutrinos and the speed of light within the margin of error.<ref name=nature2012b>{{cite web |title=Neutrinos not faster than light|publisher=NatureNews |author=Geoff Brumfiel |date=16 March 2012|accessdate=16 March 2012| doi=10.1038/nature.2012.10249|url=http://www.nature.com/news/neutrinos-not-faster-than-light-1.10249}}</ref>
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| == LNGS (2012) ==
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| Continuing the OPERA and ICARUS measurements, the [[Laboratori Nazionali del Gran Sasso|LNGS]] experiments [[Borexino]], [[Large Volume Detector|LVD]], OPERA and ICARUS conducted new tests between 10 and 24 May 2012, after CERN provided another bunched beam rerun. All measurements were consistent with the speed of light.<ref name=cernfinal /> The 17-GeV muon neutrino beam consisted of 4 batches per extraction separated by ~300ns, and the batches consisted of 16 bunches separated by ~100ns, with a bunch width of ~2ns.<ref name=borexino />
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| === Borexino ===
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| The Borexino collaboration analyzed both the bunched beam rerun of Oct.–Nov. 2011 and the second rerun of May 2012.<ref name=borexino>{{Cite journal|author=Borexino collaboration|title=Measurement of CNGS muon neutrino speed with Borexino|journal=Physics Letters B|volume=716|issue=3–5|pages=401–405|year=2012|doi=10.1016/j.physletb.2012.08.052|arxiv=1207.6860|bibcode = 2012PhLB..716..401A }}</ref>
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| For the 2011 data, they evaluated 36 neutrino events and obtained an upper limit for time of flight differences:
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| :<math>\delta t=-6.5\pm7\ (\mathrm{stat.}) \pm6\ (\mathrm{sys.})</math> nanoseconds.
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| For the May 2012 measurements, they improved their equipment by installing a new analogue small–jitter triggering system and a geodetic GPS receiver coupled to a [[Rubidium|Rb]] clock.<ref name=Caccianiga>{{Cite journal|author=Caccianiga ''et al''.|title= GPS-based CERN-LNGS time link for Borexino|journal=Journal of Instrumentation|volume=7|pages=P08028|year=2012|doi=10.1088/1748-0221/7/08/P08028|arxiv=1207.0591|bibcode = 2012arXiv1207.0591C|issue=8 }}</ref> They also conducted an independent high precision geodesy measurement together with LVD and ICARUS. 62 neutrino events could be used for the final analysis, giving a more precise upper limit for time of flight differences<ref name=borexino />
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| :<math>\delta t=0.8\pm0.7\ (\mathrm{stat.}) \pm2.9\ (\mathrm{sys.})</math> nanoseconds,
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| corresponding to
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| :<math>\frac{|v-c|}{c}<2.1\times10^{-6}</math> (90% C.L.).
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| === LVD ===
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| The [[Large Volume Detector|LVD]] collaboration first analyzed the beam rerun of Oct.–Nov. 2011. They evaluated 32 neutrino events and obtained an upper limit for time of flight differences:<ref name=lvd12>{{Cite journal|author=LVD collaboration|title=Measurement of the velocity of neutrinos from the CNGS beam with the Large Volume Detector |journal=Physical Review Letters|volume=109|issue=7|pages= 070801|year=2012|doi=10.1103/PhysRevLett.109.070801|arxiv=1208.1392|bibcode = 2012PhRvL.109g0801A|pmid=23006352 }}</ref>
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| :<math>\delta t=3.1\pm5.3\ (\mathrm{stat.}) \pm8\ (\mathrm{sys.})</math> nanoseconds.
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| In the May 2012 measurements, they used the new LNGS timing facility by the Borexino collaboration, and the geodetic data obtained by LVD, Borexino, and ICARUS (see above). They also updated their [[Scintillation counter]]s and the [[Trigger (particle physics)|trigger]]. 48 neutrino events (at energies above 50 MeV, average neutrino energy was 17 GeV) have been used for the May analysis, improving the upper limit for time of flight differences<ref name=lvd12 />
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| :<math>\delta t=0.9\pm0.6\ (\mathrm{stat.}) \pm3.2\ (\mathrm{sys.})</math> nanoseconds,
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| corresponding to
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| :<math>-3.8\times10^{-6}<\frac{v-c}{c}<3.1\times10^{-6}</math> (99% C.L.).
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| === ICARUS ===
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| After publishing the analysis of the beam rerun of Oct.–Nov. 2011 (see [[#ICARUS (2012)|above]]), the ICARUS collaboration also provided an analysis of the May rerun. They substantially improved their own internal timing system and between CERN-LNGS, used the geodetic LNGS measurement together with Borexino and LVD, and employed Borexino's timing facility. 25 neutrino events have been evaluated for the final analysis, yielding an upper limit for time of flight differences:<ref>{{Cite journal|author=ICARUS collaboration|title=Precision measurement of the neutrino velocity with the ICARUS detector in the CNGS beam |journal=Journal of High Energy Physics|issue=11|pages=49|year=2012|doi=10.1007/JHEP11(2012)049|arxiv=1208.2629|bibcode = 2012JHEP...11..049A|volume=2012 }}</ref>
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| :<math>\delta t=0.18\pm0.69\ (\mathrm{stat.}) \pm2.17\ (\mathrm{sys.})</math> nanoseconds,
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| corresponding to
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| :<math>\frac{v-c}{c}=(0.7\pm2.8\ (\mathrm{stat.})\pm8.9\ (\mathrm{sys.}))\times10^{-7}</math>.
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| Neutrino velocities exceeding the speed of light by more than <math>1.6\times10^{-6}c</math> (95% C.L.) are excluded.
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| === OPERA ===
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| After the correction of the initial results, OPERA published their May 2012 measurements as well.<ref>{{Cite journal | author=OPERA collaboration|title=Measurement of the neutrino velocity with the OPERA detector in the CNGS beam using the 2012 dedicated data | journal=Journal of High Energy Physics| issue=1 | pages=153 | year=2013 | doi=10.1007/JHEP01(2013)153|arxiv=1212.1276|bibcode = 2013JHEP...01..153A }}</ref>
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| An additional, independent timing system and four different methods of analysis were used for the evaluation of the neutrino events. They provided an upper limit for time of flight differences between light and muon neutrinos (48 to 59 neutrino events depending on the method of analysis):
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| :<math>\delta t=0.6\pm0.4\ (\mathrm{stat.}) \pm3.0\ (\mathrm{sys.})</math> nanoseconds,
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| and between light and anti-muon neutrinos (3 neutrino events):
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| :<math>\delta t=1.7\pm1.4\ (\mathrm{stat.}) \pm3.2\ (\mathrm{sys.})</math> nanoseconds,
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| consistent with the speed of light in the range of
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| :<math>-1.8\times10^{-6}<\frac{v-c}{c}<2.3\times10^{-6}</math> (90% C. L.).
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| | |
| == MINOS (2012) ==
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| | |
| === Old timing system ===
| |
| The MINOS collaboration further elaborated on their speed measurements of 2007. They examined the data collected over seven years, improved the GPS timing system and the understanding of the delays of electronic components, and also used upgraded timing equipment. The neutrinos span a 10 [[Microsecond|μs]] spill containing 5-6 batches. The analyses have been conducted in two ways. First, as in the 2007 measurement, the data at the far detector was statistically determined by the data of the near detector ("Full Spill Approach"):<ref>{{Cite journal|author=Adamson, P.|title=Neutrino Velocity: Results and prospects of experiments at beamlines other than CNGS|journal=Nuclear Physics B Proceedings Supplements|volume=235|pages= 296–300|year=2013|doi=10.1016/j.nuclphysbps.2013.04.025|url=http://inspirehep.net/record/1233787|bibcode = 2013NuPhS.235..296A }}</ref><ref>{{cite web|title=MINOS reports new measurement of neutrino velocity |publisher=Fermilab today|url=http://www.fnal.gov/pub/today/archive_2012/today12-06-08.html|date=8 June 2012|accessdate=8 June 2012}}</ref>
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| :<math>\delta t=-18\pm11\ (\mathrm{stat.}) \pm29\ (\mathrm{sys.})</math> nanoseconds,
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| Second, the data connected with the batches themselves have been used ("Wrapped Spill Approach"):
| |
| | |
| :<math>\delta t=-11\pm11\ (\mathrm{stat.}) \pm29\ (\mathrm{sys.})</math> nanoseconds,
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| This is consistent with neutrinos traveling at the speed of light, and substantially improves their preliminary 2007 results.
| |
| | |
| === New timing system ===
| |
| In order to further improve the precision, a new timing system was developed. In particular, a "Resistive Wall Current Monitor" (RWCM) measuring the time distribution of the proton beam, CS atomic clocks, dual frequency GPS receivers, and auxiliary detectors to measure detector latencies have been installed. For the analysis, the neutrino events could be connected with a specific 10μs proton spill, from which a likelihood analysis was generated, and then the likelihoods of different events have been combined. The result:<ref>{{Cite journal|author=P. Adamson et al.|title=Measurement of the Velocity of the Neutrino with MINOS|journal=Proceedings of the 44th Annual Precise Time and Time Interval Systems and Applications Meeting|pages=119–132|year=2012|url=http://inspirehep.net/record/1223915}}</ref><ref>{{cite web|title=Exceeding the speed limit? Measuring neutrinos to the nanosecond |publisher=Fermilab today|url=http://www.fnal.gov/pub/today/archive/archive_2013/today13-04-12.html|date=13 April 2013|accessdate=13 April 2013}}</ref>
| |
| | |
| :<math>\delta t=-2.4\pm0.1\ (\mathrm{stat.}) \pm2.6\ (\mathrm{sys.})</math> nanoseconds,
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| and
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| :<math>\frac{v-c}{c}=(1.0\pm1.1)\times10^{-6}</math>.
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| | |
| Additional precision measurements are planned with the improved [[MINOS+]] detector.
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| | |
| == Indirect determinations of neutrino speed ==
| |
| Lorentz violating frameworks such as the [[Standard-Model Extension]] including [[Lorentz-violating neutrino oscillations]] also allow for indirect determinations of deviations between light speed and neutrino speed by measuring their energy and the decay rates of other particles over large distances.<ref name=diaz /> By this method, much more stringent bounds can be obtained, such as by Borriello ''et al.'':<ref>{{Cite journal|author=Borriello ''et al.''|title=Stringent constraint on neutrino Lorentz invariance violation from the two IceCube PeV neutrinos|journal=Physical Review D|volume=87|issue=11|pages=116009|doi=10.1103/PhysRevD.87.116009|arxiv=1303.5843|year=2013|bibcode = 2013PhRvD..87k6009B }}</ref>
| |
| | |
| :<math>\frac{|v-c|}{c}<10^{-18}</math>.
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| For more such indirect bounds on superluminal neutrinos, see [[Modern searches for Lorentz violation#Neutrino speed]].
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| | |
| == References ==
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| {{reflist|colwidth=30em}}
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| | |
| == External links ==
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| * INFN resource list with many papers on experiments and history: [http://www.nu.to.infn.it/SuperLuminal_Neutrino/ SuperLuminal Neutrino]
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| | |
| {{Tests of special relativity}}
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| {{Use dmy dates|date=June 2013}}
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| [[Category:Physics experiments]]
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| [[Category:Special relativity]]
| |
Different people have different goals in mind when working on their home. Some are tired of the old look. Other people seek to raise the value of their home through improvements. While still others do it simply because they enjoy working with their hands. Whatever your motivation is, these tips will put you on the right path.
If you have a large garden but would like more indoor living space, adding a conservatory is one home improvement you should consider. A conservatory will provide an additional room to your house that will be filled with natural light. The room can be used for moonlit dinners, home gym equipment, sun lounges and much more. The structure is also likely to catch the eye of potential buyers and increase the resale value of your home.
If you have a cabinet door that just won't stay closed, try replacing the cabinet lock. You might want to try using a magnetic cabinet lock, as they generally last longer than wheel based cabinet lock systems. Simply remove the old lock and attach the new lock in the same location. Use wood screws if needed to create new holes.
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Before you start painting a room, it is best to know about how much paint you need. Measure the length of the walls in the room you plan to paint and add them together. Next, measure the height of the room. Multiply the height by the length. The square foot of the room is the answer you get. One gallon of paint will generally cover 350 square feet.
Take your trash out at least once a day. Don't let your trash pile in the kitchen because it attracts flies and ants as well as mold. Make sure that you don't let your trash take over your kitchen and set aside three minutes a day when you throw it out.
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A great home improvement tip is to not let your ego get in the way when making renovations. Sometimes, a renovation you may have in mind does not need to be done because it could violate a particular building code, or it could even harm the value of your home.
When you are designing your kitchen, think hard about whether you want an open or closed kitchen floor plan. If you like to be able to talk with your family, watch television and generally know what's going on in the rest of the house while cooking, you may want an open kitchen plan. However, if you would prefer for the kitchen clutter to stay hidden, you may prefer a kitchen with a door that can be closed.
Kitchen cabinets can be extremely heavy. Make them lighter by removing the doors and drawers from all of your new cabinets before installing them. The lighter cabinets will be easier to maneuver and there will be nothing to get in your way as you screw the cabinets to the wall.
A deck can be a great addition to your home, but you need to be on the lookout for the common telltale signs that indicate your deck is due for maintenance. You may find uneven boards, cracks in wood or handrails or even dry rot. Take a closer look to find nails and screws that need replacing.
Your home is one of your most valuable financial assets, and it is the place where you spend a majority of your time. So the next time you spot something that could use a little maintenance, you owe it to yourself, and to your wallet, to try your hand at fixing up your home!
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