Recommended by us: Neutrinos and non-standard interactions

“ Does matter matter for neutrino flavor? The NuMI (Neutrinos at the Main Injector) beam is generated here at Fermilab and points toward the Soudan Underground Laboratory in Soudan, Minn. The MINOS collaboration detects this beam of neutrinos in its journey twice: once at Fermilab right after it is generated and once at Soudan Lab after the neutrinos have traveled 450 miles through the Earth's crust. At its generation, the beam is made up of muon-flavored neutrinos (neutrinos come in three flavors: electron, muon, and tau). After traveling such a long distance, some of the neutrinos change flavor, primarily into tau neutrinos and a few into electron neutrinos. This phenomenon of flavor change is called neutrino oscillation. By counting the number (and measuring the energy) of muon neutrinos before and after travel, MINOS can measure parameters that govern neutrino oscillations.             The presence of matter in the neutrino path may also have an impact on flavor change. If it does, the flavor              count after travel would be altered. Some of these interactions are expected from the tiny number of oscillation             generated electron neutrinos, but extra interactions of muon or tau neutrinos with the Earth are non-standard and             are thus called non-standard interactions, or NSI for short. (The Earth is made up of regular matter—electrons,              protons and neutrons—and not of matter in muon or tau flavors.) By combining its neutrino and antineutrino data sets, MINOS has constrained the non-standard interaction parameter εμτ, finding that the results are consistent with εμτ=0, shown by the gray line. The angle θ and the parameter Δm2 relate to the relative masses of the neutrinos and to how quantum mechanically "mixed" the flavors are.                                                                                               (Continue to read on Fermilab Today)                  ”

Recommended by us: CERN and Sterile Neutrinos

CERN Set to Study Sterile Neutrinos

by Edwin Cartlidge on 5 February 2013

“ 

A new experimental facility to detect a hypothetical particle that many physicists think probably doesn't exist could be up and running at the CERN laboratory near Geneva, Switzerland, within 3 years, assuming that the lab's member states approve spending roughly $110 million to build it.

The sterile neutrino, if it exists, would be an obscure variety of an already otherworldly subatomic particle. Ordinary neutrinos, which have no charge and almost no mass, come in three varieties: electron, muon, and tau. They are very hard to detect because their interaction with ordinary matter is extremely feeble, but over the years physicists have detected enough of them to observe that as they travel through space they can "oscillate" from one flavour to another.

This oscillation phenomenon, which means that neutrinos cannot be entirely massless, has been confirmed by many different experiments. But one such experiment produced results at odds with the rest. That was the Liquid Scintillator Neutrino Detector (LSND) at the Los Alamos National Laboratory in New Mexico, which in data acquired between 1993 and 1998 showed muon antineutrinos to be oscillating into electron antineutrinos far more readily than expected.

(Continue to read on news.sciencemag.org)

                    ”

Recommended by us: Backreaction on the Anthropic Principle

Waiting to have more time to tell my experience in Cambridge, MA [January has been crazy: two removals, VISA problems, accommodation searches, etc...] let me just suggest a beautiful post by the Backreaction blog. I enjoyed the reading a lot and I suggest to follow the discussion in the comments.

Recommended by us: Organizing the masses at MINOS

Organizing the masses at MINOS

“ 

By combining its neutrino and antineutrino data sets, 

MINOS  has  provided first constraints on the spectrum 

of neutrino masses (represented by the sign of Δm2), the 

CP-violating phase δ,and whether muon or tau neutrinos 

are more strongly mixed  with the so-called ν3 mass state 

(indicated by θ23). The relative goodness of each scenario

 is given along the vertical axis in terms of a difference of 

log-likelihoods. The parameter Δm2 and the angles θ13 

and θ23 relate to the relative masses of the neutrinos and

to how quantum mechanically "mixed" the three types are.

Over a decade ago the evidence became clear that neutrinos, which come in three varieties, can morph from one type to another as they travel, a phenomenon known as neutrino oscillation. By tallying how often this transformation happens under various conditions—different neutrino energies, different distances of travel—one can tease out a number of fundamental properties of neutrinos, for example, their relative masses. The MINOS collaboration has been doing exactly this by sending an intense beam of muon-type neutrinos from Fermilab to northern Minnesota, where a 5-kiloton detector lies in wait deep underground.

In this new result, MINOS has observed the rare case of muon-type neutrinos changing into electron-type neutrinos. This transformation is governed by a parameter known as θ13, and the MINOS data provide new constraints on θ13 using different experimental techniques than previous measurements. MINOS also collected data with an antineutrino beam, and the real excitement comes in when combining the antineutrino and neutrino data sets. Differences between the rates of this particular oscillation mode between neutrinos and antineutrinos would point to a violation of something called CP symmetry. While physicists know that CP symmetry is violated by quarks, it remains unknown whether the same is true for neutrinos. A new source of CP violation is required to explain why the universe began with more particles than antiparticles, and neutrinos could hold the key. (If the universe began with equal numbers of particles and antiparticles, they would have subsequently annihilated away, leaving nothing left over to make the stars and galaxies we have today.)

(Continue to read on Fermilab Today)

                    ”

Recommended by us: Boson

“  Bosons All particles fall into one of two classes, bosons or fermions. Two bosons with identical properties can be in the same place at the same time, but two fermions cannot.           By Sean Carroll, California Institute of Technology There are two kinds of elementary particles in the universe: bosons and fermions. Bosons don’t mind sitting on top of each other, sharing the same space. In principle, you could pile an infinite number of bosons into the tiniest bucket. Fermions, on the other hand, don’t share space: only a limited number of fermions would fit into the bucket. Matter, as you might guess, is made of fermions, which stack to form three-dimensional structures. The force fields that bind fermions to each other are made of bosons. Bosons are the glue holding matter together. Bosons and fermions act like two different kinds of spinning tops. Even when a boson or fermion is by itself, it always has an intrinsic angular momentum, which scientists call spin. Bosons always have an integer amount of spin (0, 1, 2...), while fermions have half-integer spin (1/2, 3/2, 5/2...).  Before July 2012, every fundamental particle that physicists had discovered had non-zero spin. But the theory behind the Higgs boson predicts that it should have no spin. If the early indications hold up and the new particle discovered at the Large Hadron Collider really is the Higgs boson, it will be the first known example of an elementary particle that knows no direction and no polarization—a truly revolutionary discovery.                                                                                                                                                                                                                          (From: http://www.symmetrymagazine.org)                   ”

“Person of the Year” Nomination for Higgs Boson Riddled with Errors

“ Time magazine recently posted 30 nominations for its ever-popular “Person of the Year” award. Tucked in between President Barack Obama and the Korean rapper Psy is an unlikely candidate for the “Person of the Year”—a subatomic particle. As Scientific American readers are well aware, physicists at the Large Hadron Collider announced this summer that they had found something that looks much like long-elusive Higgs boson, causing a brief but wondrous worldwide bout of Higgsteria.  (continue reading Michael Moyer on scientificamerican)

                 ”

Primarie del centrosinistra, domande e risposte su scienza e ricerca

“

Fecondazione assistita, OGM, politiche energetiche, sicurezza del territorio e altro ancora. Un gruppo di giornalisti, blogger, ricercatori e cittadini chiede ai candidati alle primarie del centrosinistra di dichiarare la loro posizione concreta su sei temi centrali delle politiche della scienza e della ricerca (red)

Alla fine, tutti e cinque i candidati alle primarie del centrosinistra hanno risposto alle domande in materia di scienza e ricerca che un gruppo di giornalisti scientifici, blogger, ricercatori e cittadini, ha proposto loro a partire dall'iniziativa proposta dal gruppo Facebook "Dibattito Scienza".

Pubblichiamo qui le risposte dei candidati, ringraziando tutti coloro che con noi hanno lavorato con passione e impegno per portare la scienza sulla scena del dibattito politico. In questa pagina, in basso, daremo conto anche dei commenti che appariranno su blog e siti Internet riguardo a questa iniziativa. Segnalateceli.

Le domande e le risposte

1. Quali politiche intende perseguire per il rilancio della ricerca in Italia, sia di base sia applicata, e quali provvedimenti concreti intende promuovere a favore dei ricercatori più giovani?

Pierluigi Bersani
Laura Puppato
Matteo Renzi
Bruno Tabacci
Nichi Vendola 

                                                                                             Continua a leggere sul sito de LeScienze

                    ”

How to Make a Neutrino Beam

“ How to make a neutrino beam

Neutrinos are elusive particles that are difficult to study, yet they may help explain some of the biggest mysteries of our universe. Using accelerators to make neutrino beams, scientists are unveiling the neutrinos’ secrets.

By Jessica Orwig

Neutrinos are among the most abundant particles in the universe, but they rarely interact with matter. Some of today’s outstanding scientific mysteries, such as why there is more matter than antimatter in the universe, could be solved by studying neutrinos and detecting their interactions with matter.

Billions of neutrinos from natural sources, including the Sun, zip through every square centimeter of the Earth each second. Yet scientists cannot easily determine their initial type or exactly how far they traveled before reaching a detector.

To study neutrinos more effectively, scientists produce high-intensity neutrino beams using proton accelerators. Only a few laboratories in the world can manufacture such neutrino beams: the J-PARC laboratory in Japan, the research center CERN in Europe and Fermi National Accelerator Laboratory in the United States.  Every two seconds, Fermilab fires a trillion neutrinos toward particle detectors located in northern Minnesota, more than 450 miles away. This intense beam produces about a thousand neutrino interactions per year in the detectors. 

Continue to read on: http://www.symmetrymagazine.org

                 ”

Le leggi della fisica sono un suggerimento: "Think Different"!!

Credo che le reazioni al nuovo spot pubblicitario del iPhone 5 (spot che puoi rivedere a questo link), soprattutto da parte di quell'utenza che è vicina al mondo della scienza, siano state un po' tutte di  forte "stupore". Purtroppo, da quello che ho potuto appurare, non si è trattato tanto di una meraviglia sana nei confronti dello spot, quanto piuttosto di una sensazione di "smarrimento" e incredulità che culmina all'ascolto dello slogan "[...] forse le leggi della fisica sono solo dei suggerimenti". 

Recommended by us: gravitons

“  Gravitons Sesame Street has a learning game that goes with the jingle "One of these things is not like the other. One of these things just doesn't belong." Can you find which one is different? If you've read anything about the kinds of physics we do at Fermilab, you've heard lots of words ending with "on" – words like proton, neutron, gluon, photon, boson, fermion and on and on and on. One of the words you might have encountered is the graviton. Let's get one thing out of the way: At the moment, gravitons are entirely theoretical constructs that delicately walk the knife-edge precipice between the domains of scientific respectability and the shady world of hand waving. The fantastic success of quantum theory to describe three forces – electromagnetism and the strong and weak nuclear forces – provides a considerable impetus to try to marry it to the fourth force of gravity. In the same way that the photon is known to be the quantum particle of the electromagnetic force and the gluon is the quantum particle of the strong force, the "graviton" is the name given to a hypothetical quantum particle of the gravitational force. However, a quantum theory of gravity has so far been elusive. Einstein's theory of general relativity has been the most successful description of gravity, but when it encounters the quantum realm, it predicts nonsense, with impossible infinities popping up throughout the calculations. Infinities like that are nature's way of saying "back to the drawing board." And though theoretical physicists have quite a way to go in coming up with such a model, it is still possible to work out some of the properties of gravitons. (Continue to read on Fermilab Today)

                 ”

Recommended by us: L'accorpamento che non capisci

“ ASTRI E PARTICELLE di Roberto Battiston Colpo di mano sugli Enti di Ricerca: super CNR mangia-tutto ?  Siamo in un Paese curioso. Sappiamo di avere croniche, storiche disfunzioni organizzative a livello di sistema.  Sapevamo  però  anche di avere eccellenze  distribuite su tutto il territorio ed in vari settori della ricerca,  con enti di ricerca che producono ottimi risultati, in alcuni  casi eccellenze a livello planetario, nonostante un carico burocratico  e di vincoli amministrativi  in continua crescita  che provocano, tra le altre cose, la fuga dei giovani migliori e di conseguenza  un invecchiamento insostenibile dell’età media dei ricercatori.  Pensavamo che dopo quasi un decennio di manipolazioni di pezzi del sistema degli enti pubblici di ricerca in particolare: - accorpamento Osservatori-Istituti del CNR nel settore spaziale con la nascita dell’ INAF agli inizi del 2000, -creazione dell’ INFM con l’uscita dei corrispondenti istituti del settore della fisica della materia dal CNR, - abolizione dell’ INFM (Ministro Moratti) con il riassorbimento  nel CNR, nonostante gli ottimi risultati della valutazione CIVR - riordino di tutti i 12 gli enti di ricerca vigilati dal MIUR  (Ministro Mussi e poi Gelmini)  durato quasi due anni con il conseguente cambio contemporaneo di tutti i vertici nel 2011 ed il corrispondente  riordino dei meccanismi di gestione solo per citare alcune delle cose più importanti accadute in questi anni, si fosse arrivati ad una situazione in cui ci si potesse finalmente concentrare sulle attività ordinarie della ricerca e non sulle norme su come si organizza e si gestisce la ricerca.  (Continua a leggere su LeScienze Blog)

                 ”

Vedi anche "Super accorpamento: Profumo incontra i presidenti degli Enti di ricerca".

Mainstream metronomes

“ You are getting sleeeeeeepy….. by Julianne Dalcanton Ikeguchi Laboratories has posted one of the most fantastic “physics in action” videos I’ve seen in a long time: The concept is simple — 32 metronomes on a table, all set to the same tempo, but started at slightly different times. But here’s the fun bit — although they begin “out of phase“, after about 2 minutes, they all lock onto the same phase and synchronize! (Well, almost all — there’s a rebel on the far right that takes an extra minute to get with the program). (Continue to read on cosmicvariance)

                 ”

Recommended by us: Majorana or Dirac?

Before to make a report on the participation to the workshop "BeNe" (Behind the Neutrino Mass) I would like to instill curiosity about one of the fundamental themes of neutrino physics: the neutrino is a Dirac or Majorana particle? The explanation offered here is simple but captures well the essence of the problem so I recommend reading.

Book Review: “The Geek Manifesto” [Via BackReaction]

“ Book Review “The Geek Manifesto” by Mark Henderson The Geek Manifesto: Why Science Matters By Mark Henderson Bantam Press (10 May 2012) Henderson’s book is a well-structured and timely summary of why science, both scientific knowledge and the scientific method, matters for the well-being of our societies. Henderson covers seven different areas: why science matters to politics, the government, the media, the economy, education, in court, in healthcare and to the environment. In each case, he has examples of current problems, mostly from  (Continue to read on BackReaction)

                 ”

Recommended by us: Violation of the "first" Heisenberg's Uncertainty Principle

“ Synopsis: The Certainty of Uncertainty L. A. Rozema et al. Phys. Rev. Lett. (2012) Violation of Heisenberg’s Measurement-Distrurbance                                           Relationship by Weak Measurements Lee A. Rozema, Ardavan Darabi, Dylan H. Mahler, Alex Hayat,                                   Yasaman Soudagar, and Aephraim M. Steinberg Phys. Rev. Lett. 109, 100404 (2012) Published September 6, 2012 When first taking quantum mechanics courses, students learn about Heisenberg’s uncertainty principle, which is often presented as a statement about the intrinsic uncertainty that a quantum system must possess. Yet Heisenberg originally formulated his principle in terms of the “observer effect”: a relationship between the precision of a measurement and the disturbance it creates, as when a photon measures an electron’s position. Although the former version is rigorously proven, the latter is less general and—as recently shown—mathematically incorrect. In a paper in Physical Review Letters, Lee Rozema and colleagues at the University of Toronto, Canada, experimentally demonstrate that a measurement can in fact violate Heisenberg’s original precision-disturbance relationship. (Continue to read on physics.aps.org)

                 ”

Recommended by us

“Questioning the Foundations The submission deadline for this year’s FQXi essay context on the question “Which of Our Basic Physical Assumptions Are Wrong?” has just passed. They got many thought-provoking contributions, which I encourage you to browse here. The question was really difficult for me. Not because nothing came to my mind but because too much came to my mind! Throwing out the Heisenberg uncertainty principle, Lorentz-invariance, the positivity of gravitational mass, or the speed of light limit – been there, done that. And that’s only the stuff that I did publish...

(Continue to read on BackReaction)                                                                                                                                 ”

The (business) rule of Nature

“ Guest Post: Terry Rudolph on Nature versus Nurture

by Sean Carroll

Everyone always wants to know whether the wave function of quantum mechanics is “a real thing” or whether it’s just a tool we use to calculate the probability of measuring a certain outcome. Here at CV, we even hosted a give-and-take on the issue between instrumentalist Tom Banks and realist David Wallace. In the latter post, I linked to recent preprint on the issue that proved a very interesting theorem, seemingly boosting the “wave functions are real” side of the debate.

That preprint was submitted to Nature, but never made it in (although it did ultimately get published in Nature Physics). The story of why such an important result was shunted away from the journal to which it was first submitted (just like Peter Higgs’s paper where he first mentioned the Higgs boson!) is interesting in its own right. Here is that story, as told by Terry Rudolph, an author of the original paper. Terry is a theoretical physicist at Imperial College London, who “will  work on anything that has the word `quantum’ in front of it.” (continue to read on Cosmic Variance) .                                                                                                                                        ” 

Recommended by us

In this post I have talked about the hypothetical variability of nuclear decay rate related to solar-earth distance and solar flares. But what is a subatomic decay?

“What is subatomic decay? One type of decay in the subatomic realm occurs when an existing object simply fissions into two smaller objects. In this case, the makeup of the initial particle and decay products are just moved around, as when a column breaks into pieces. One example is when a uranium nucleus breaks into thorium and helium nuclei. Decay evokes a lot of images, from jumbled piles of stone that once composed breathtaking examples of architecture to the dank smell of a damp forest glen, with the rot of wet leaves and crumbling tree stumps filling your lungs. The word decay also shows up a lot in Fermilab Today articles, which often talk about the decay of this particle or that. Is it possible that you, the reader, might be applying a common meaning to this most uncommon situation? Just what does this familiar word mean in a particle physics context? In particle physics, decay means that a particular particle disappears and is replaced by two or more so-called decay products. Conjuring up a human metaphor, we call the initial particle a mother particle and the decay products the daughter particles. The daughter particles can in turn decay into granddaughter particles and so on until you get the final product. So let's talk about the decay of subatomic particles. There are three broad classes. We'll start with the easier ones and work our way up to the more mind-bending ones. (Continue to read on Fermilab Today)                                                                                                                                 ”