How Do You Make Neutrino Beam?

This new Don Lincoln's video is related to the one he did previously on the PIP-II upgrade at Fermilab. This time, he tells you how they make neutrino beams at Fermilab.



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CP Violation in D Meson Decay

LHCb is reporting the first evidence of CP violation in the decay of D meson.

The D⁰ meson is made of a charm quark and an up antiquark. So far, CP violation has only been observed in particles containing a strange or a bottom quark. These observations have confirmed the pattern of CP violation described in the Standard Model by the so-called Cabibbo-Kobayashi-Maskawa (CKM) mixing matrix, which characterises how quarks of different types transform into each other via weak interactions. The deep origin of the CKM matrix, and the quest for additional sources and manifestations of CP violation, are among the big open questions of particle physics. The discovery of CP violation in the D⁰ meson is the first evidence of this asymmetry for the charm quark, adding new elements to the exploration of these questions.

If confirmed, this will be another meson that has exhibited such CP violation, and adds to the argument that such symmetry violation could be the source of our matter-antimatter asymmetry in this universe.

CP violation is an essential feature of our universe, necessary to induce the processes that, following the Big Bang, established the abundance of matter over antimatter that we observe in the present-day universe. The size of CP violation observed so far in Standard Model interactions, however, is too small to account for the present-day matter–antimatter imbalance, suggesting the existence of additional as-yet-unknown sources of CP violation.

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PIP-II Upgrade At Fermilab

Don Lincoln explains why the PIP-II upgrade at Fermilab will take the accelerator facility to the next level.



The video actually explains a bit about how particle accelerator works, and the type of improvement that is being planned for.

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Standing Out From The Crowd In Large Collaboration

As someone who has never been involved in these huge collaborations that we see in high energy physics, I've often wondered how a graduate student or a postdoc make a name for themselves. If you are one of dozens, even hundreds, of authors in a paper, how do you get recognized?

It seems that this issue has finally been addressed by the high energy physics community, at least in Europe. A working group has been established to look into ways for students, postdocs, and early-career researches to stand out from the crowd and have their effort recognized individually.

To fully exploit the potential of large collaborations, we need to bring every single person to maximum effectiveness by motivating and stimulating individual recognition and career choices. With this in mind, in spring 2018 the European Committee for Future Accelerators (ECFA) established a working group to investigate what the community thinks about individual recognition in large collaborations. Following an initial survey addressing leaders of several CERN and CERN-recognised experiments, a community-wide survey closed on 26 October with a total of 1347 responses. 

Still, the article does not clarify on exactly how these individual recognition can be done. I'd be interested to hear how they are going to do this.

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Fermilab

Do you ever want to know about US Fermi National Accelerator Laboratory, or Fermilab?

Don Lincoln finally has made a video on everything you want to know about Fermilab, especially if you think that they don't do much anymore nowadays now that the Tevatron is long gone.



As someone who has visited there numerous times and collaborated with scientists and engineers that this facility, it is a neat place to visit if you have the chance.

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Tommaso Dorigo's "False Claims In Particle Physics"

Hey, you should read this blog post by Tommaso Dorigo. It touches upon many of the myths regarding particle physics, especially the hype surrounding the name "god particle", as if that means something.

I've touched upon some of the issues he brought up. I think many of us who are active online and deal with the media and the public tend to see and observe the same thing, the same mistakes, and misinformation that are being put in print. One can only hope that by repeatedly pointing out such myths and why they are wrong, the message will slowly seep into the public consciousness.

I just wish it is seeping through faster.

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Crisis? What Crisis?

Chad Orzel has posted a fun piece that really tries to clarified all the brouhaha in many circles about a "crisis" that many are presuming to be widespread. The crisis in question is the lack of "beyond the standard model" discovery in elementary particle physics, and the issue that many elementary particle theorists seem to think that a theory that is based on solid foundation and elegance are sufficient to be taken seriously.

I find this very frustrating, because physics as a whole is not in crisis. The "crisis" being described is real, but it affects only the subset of physics that deals with fundamental particles and fields, particularly on the theory side. (Experimental physicists in those areas aren't making dramatic discoveries, but they are generating data and pushing their experiments forward, so they're a little happier than their theoretical colleagues...)

The problems of theoretical high energy physics, though, do not greatly afflict physicists working in much of the rest of the discipline. While this might be a time of crisis for particle theorists, it's arguably never been a better time to be a physicist in most of the rest of the field. There are exciting discoveries being made, and new technologies pushing the frontiers of physics forward in a wide range of subfields.

This is a common frustration, because elementary particle physics is not even the biggest subfield of physics (condensed matter physics is), but yet, it makes a lot of noise, and the media+public seem to pay more attention to such noises. So whenever something rocks this field, people often tend to think that this permeates through the entire field of physics. This is utterly false!

Orzel has listed several outstanding and amazing discoveries and advancements in condensed matter. There are more! The study of topological insulators continues to be extremely hot and appear to be not only interesting for application, but also as a "playground" for exotic quantum field theory scenarios.

I've said it many times, and I'll say it again. Physics isn't just the Higgs or the LHC. It is also your iphone, your MRI, your WiFi, your CT scan, etc....etc.

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RIP Leon Lederman

One of the most charismatic physicists that I've ever met, former Fermilab Director and Nobel Laureate Leon Lederman, has passed away at the age of 96. Most of the general public will probably not know his name, but will have heard the name "God Particle", which he coined in his book, and which he originally intended to call the "God-Damn Particle".

He had been in failing health, and suffered from dementia. It force his family to auction off his Nobel Prize medal to help with his medical cost. But his lasting legacy will be in his effort to put "Physics First" in elementary and high school. And of course, there's Fermilab.

He truly was, and still is, a giant in this field.

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Human Eye Can Detect Cosmic Radiation

Well, not in the way you think.

I recently found this video of an appearance of astronaut Scott Kelly on The Late Show with Stephen Colbert. During this segment, he talked about the fact that when he went to sleep on the Space Station and closed his eyes, he occasionally detected flashes of light. He attributed it to the cosmic radiation  passing through his body, and his eyes in particular.

Check out the video at minute 3:30



My first inclination is to say that this is similar to how we detect neutrinos, i.e. the radiation particles interact with the medium in his yes, either the vitreous or the medium that makes up the lens, and this interaction causes the ejection of relativistic electron and subsequently, a Cerenkov radiation. The Cerenkov radiation is then detected by the eye.

Of course, there are other possibilities, such as the cosmic particle causes an excitation of an atom or molecules when they collided, and this then caused a light emission. But Scott Kelly mentioned that these flashes appeared like fireworks. So my guess here is that it is more of a very short cascade of events, and probably the Cerenkov light scenario.

This, BTW, is almost how we detect neutrinos, especially at Super Kamiokande and all the neutrino detectors around the world. Neutrinos come into the detector, and those that interact with the medium inside the detector (water, for example), cause the emission of relativistic electrons that move faster than the speed of light inside the medium. This creates the Cerenkov radiation, and typically, the light is blueish white. It's the same glow that you see if you look in a pool of fuel rods in a nuclear reactor.

So there! You can detect something with your eyes closed!

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Burton Richter Dies at 87

Another giant in our field, especially in elementary  particle physics, has passed away. Burton Richter, Nobel Laureate in physics, died on July 18, 2018.

Richter’s Nobel Prize-winning discovery of the J/psi subatomic particle, shared with MIT’s Samuel Ting, confirmed the existence of the charm quark. That discovery upended existing theories and forced a recalibration in theoretical physics that reverberated for years. It became known as the “November Revolution.” One Nobel committee member at the time described it as “the greatest discovery ever in the field of elementary particles.”

He would be shortchanged if all the public ever remembers him is for his Nobel Prize discovery, because he did a whole lot more in his lifetime.

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First Human Scanned By Spectral X-Ray Scanner

Chalk this up to an application of high-energy physics in the medical diagnostic field. The first human has been scanned by a new type of x-ray scanner (registration required to read article at this moment).

The MARS scanner uses Medipix3 technology developed at CERN to produce multi-energy images with high spatial resolution and low noise. Medipix is a family of read-out chips originally developed for the Large Hadron Collider and modified for medical applications.

The Medipix3 detector measures the energy of each X-ray photon as it is detected. This spectral information is used to produce 3D images that show the individual constituents of the imaged tissue, providing significantly improved diagnostic information.

I'll repeat this, maybe to those not in the choir, that many of the esoteric experiments that you think have no relevance to your everyday lives, may turn out to be the ones that might save your lives, or the lives of your loved ones, down the road. So think about this when you talk to your elected political representatives when it comes to funding basic science.

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Super Kamiokande and Extremly Pure Water

This is a rather nice overview of Super Kamiokande, a neutrino detector in Japan. It has produced numerous ground-breaking discoveries, including the confirmation of neutrino oscillation many years ago. Unfortunately, the article omitted an important incident at Super-K several years ago when there was a massive implosion of the phototubes.

The article has an interesting information that many people might not know about extremely pure water, the type that is used to fill up the detector tank.

In order for the light from these shockwaves to reach the sensors, the water has to be cleaner than you can possibly imagine. Super-K is constantly filtering and re-purifying it, and even blasts it with UV light to kill off any bacteria.

Which actually makes it pretty creepy.

"Water that's ultra-pure is waiting to dissolve stuff into it," said Dr Uchida. "Pure water is very, very nasty stuff. It has the features of an acid and an alkaline."
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Another tale comes from Dr Wascko, who heard that in 2000 when the tank had been fully drained, researchers found the outline of a wrench at the bottom of it. "Apparently somebody had left a wrench there when they filled it in 1995," he said. "When they drained it in 2000 the wrench had dissolved." 

In other words, such pure, deionized water is not something that you want to drink.

And this leads me to comment on this silly commercial of PUR drinking water filter. It showed an ignorant public complaining about lead in the drinking water, even though he was told that the amount is below the safety level.



A drinking water contains a lot of other dissolved minerals, any one of which, above a certain limit, can be dangerous. Even that PUR commercial can only claim that it can REDUCE the amount of lead in the drinking water, not completely removed it. It will not be zero. So that guy should continue complaining about lead even with PUR filter.

If this person in the commercial is representing the general public, then the general public needs to be told that (i) you'll never be able to get rid completely of all contaminants in drinking water and (ii) pure water will dissolve your guts! This is why we set safety levels in many things (360 mrem of radiation per year, for example, is our acceptable, normal background radiation that we receive).

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Fermilab Accelerator Complex

This is a neat animation video of the Fermilab Accelerator Complex as it is now, and all the various experiments and capabilities that it has.



Of course, the "big ring", which was the Tevatron, is no longer running now, and thus, no high-energy particle collider experiments being conducted anymore.

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The Dark Life Of The Higgs Boson

I decided to modify a bit the title of the Symmetry article that I'm linking to, because in that article, the possible link between the Higgs boson and dark matter is made. This allows for the study of the decay of the Higgs to be used to detect the presence of dark matter.

The Standard Model not only predicts all the different possible decays of Higgs bosons, but how favorable each decay is. For instance, it predicts that about 60 percent of Higgs bosons will transform into a pair of bottom quarks, whereas only 0.2 percent will transform into a pair of photons. If the experimental results show Higgs bosons decaying into certain particles more or less often than predicted, it could mean that a few Higgs bosons are sneaking off and transforming into dark matter.

Of course, these kinds of precision measurements cannot tell scientists if the Higgs is evolving into dark matter as part of its decay path—only that it is behaving strangely. To catch the Higgs in the act, scientists need irrefutable evidence of the Higgs schmoozing with dark matter.

So there you have it.

If you are not up to speed on the discovery of the Higgs (i.e. you've been living under a rock for the past few years), I've mentioned a link to a nice update here.

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Table-Top Elementary Particle Experiment

I love reading articles like this one, where it shows that one can do quite useful research in elementary particles using experimental setup that is significantly smaller (and cheaper) than large particle colliders.

Now, he’s suddenly moving from the fringes of physics to the limelight. Northwestern University in Evanston, Illinois, is about to open a first-of-its-kind research institute dedicated to just his sort of small-scale particle physics, and Gabrielse will be its founding director.

The move signals a shift in the search for new physics. Researchers have dreamed of finding subatomic particles that could help them to solve some of the thorniest remaining problems in physics. But six years’ worth of LHC data have failed to produce a definitive detection of anything unexpected.

More physicists are moving in Gabrielse’s direction, with modest set-ups that can fit in standard university laboratories. Instead of brute-force methods such as smashing particles, these low-energy experimentalists use precision techniques to look for extraordinarily subtle deviations in some of nature’s most fundamental parameters. The slightest discrepancy could point the way to the field’s future. 

Again, I salute very much this type of endeavor, but I dislike the tone of the title of the article, and I'll tell you why.

In science, and especially physics, there is seldom something that has been verified, found, or discovered using just ONE experimental technique or detection method. For example, in the discovery of the Top quark, both CDF and D0 detectors at Fermilab had to agree. In the discovery of the Higgs, both ATLAS and CMS had to agree. In trying to show that something is a superconductor, you not only measure the resistivity, but also magnetic susceptibility.

In other words, you require many different types of verification, and the more the better or the more convincing it becomes.

While these table-top experiments are very ingenious, they will NOT replace the big colliders. No one in their right mind will tell CERN to "step aside", other than the author of this article. There are discoveries or parameters of elementary particles that these table-top experiments can study more efficiently than the LHC, but there are also plenty of the parameter phase space that the LHC can probe that can't be easily reached by these table-top experiments. They all are complimenting each other!

People who don't know any better, or don't know the intricacies of how experiments are done or how knowledge is gathered, will get the impression that because of these table-top experiments, facilities like the LHC will no longer be needed. I hate to think that this is the "take-home" message that many people will get.

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The Higgs - Five Years In

In case you've been asleep the past 5 years or so and what to catch up on our lovable Higgs, here is a quick, condensed version of the saga so far.

Where were you on 4 July 2012, the day the Higgs boson discovery was announced? Many people will be able to answer without referring to their diary. Perhaps you were among the few who had managed to secure a seat in CERN’s main auditorium, or who joined colleagues in universities and laboratories around the world to watch the webcast.

This story promises to have lots of sequels, just like the movies released so far this year.

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50 Years Of Fermilab

Don Lincoln takes you on a historical tour of Fermilab as it celebrates its 50th Anniversary this year.



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Planning For A Future Circular Collider

The future of the next circular collider to follow up the LHC is currently on the table. The Future Circular Collider (FCC) is envisioned to be 80-100 km in circumference (as compared to 27 km for the LHC) and reaching energy as high as 100 TeV (as compared to 13 TeV for the LHC).

Now you may think that this is way too early to think about such a thing, especially when the LHC is still in its prime and probably will be operating for a very long time. But planning and building one of these things take decades. As stated at the end of the article, the LHC itself took about 30 years from its planning stage all the way to its first operation. So you can't simply decide to get one of these built and hope to have it ready in a couple of years. It is the ultimate in long-term planning. No instant gratification here.

In the meantime, the next big project in high-energy physics collider is a linear collider, some form of the International Linear Collider that has been tossed around for many years. China and Japan look to still be the most likely place where this will be built. I do not foresee the US being a leading candidate during the next 4 years for any of these big, international facilities requiring multinational effort.

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The Search For Neutrinoless Double Beta Decay

This is a nice and simple article on why we are searching for the neutrinoless double-beta decay.

In this new study, physicists are seeking so-called neutrinoless double-beta decay. Normally, some radioactive atoms' unstable nuclei will lose a neutron via beta decay — the neutron transforms into a proton by releasing an electron and a tiny particle called an electron antineutrino. A mirror image can also occur, in which a proton turns into a neutron, releasing a positron and an electron neutrino — the normal-matter counterpart to the antineutrino. Double-beta decay happens when two electrons and two antineutrinos (the antimatter counterparts of neutrinos) are released: basically, the beta decay happens twice. Scientists have long theorized a neutrinoless version of this process — something that would suggest that the two neutrinos annihilated each other before being released from the atom. Essentially, the neutrino behaves as its own antimatter sibling.

A large portion of high-energy physics experiments around the world are done using neutrinos (Daya Bay, MINOS, NOvA, SuperK, etc...).  It won't surprise me one bit that the another major discovery will be made with these particles.

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Fermilab's Greatest Hits

Highlights from the first 50 years at the historic Fermi National Accelerator Laboratory.



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