Queue of lonely chairs to meet a model of the LHCb experiment

#b2 #lhcb #model #CERN #lonelychairsatcern

LHCb detector bevestigt de lepton-universaliteit van het standaardmodel

LHCb detector bevestigt de lepton-universaliteit van het standaardmodel

Het LHCb experiment. Credit: LHCb Collaboration.
Een nieuwe analyse van metingen met de LHCb-detector bij CERN aan zeldzame B-vervallen toont vergelijkbaar gedrag aan tussen muonen en elektronen. Dit is verwacht in het standaardmodel, maar toch zeer raadselachtig, aldus LHCb-fysici. De nieuwe resultaten werden dinsdagochtend bekendgemaakt tijdens een seminar bij CERN in Genève over de zogenaamde…

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LHCb-experiment bevestigt mogelijk afwijking van standaard deeltjestheorie

LHCb-experiment bevestigt mogelijk afwijking van standaard deeltjestheorie

Het LHCb-experiment van CERN bij Genève heeft mogelijke afwijkingen van de deeltjestheorie gevonden die aansluiten bij wat andere experimenten zien. Dat kan opnieuw een aanwijzing zijn voor nieuwe onbekende deeltjes.
Het nieuwe LHCb22 resultaat, samen met eerdere metingen van andere experimenten als BarBar en Belle. Het rode ovaal is het wereldgemiddelde, het zwarte kruisje wat het Standaardmodel…

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Opwinding over Rk en g-2

Opwinding over Rk en g-2

Een B0 meson vervalt in een K*0 en een electron–positron paar in de LHCb detector. Credit: LHCb Collaboration.
Goh, lekker vage titel Arie, ‘Opwinding over Rk en g-2′. Nee niet gelijk afhaken, het is écht opwindend en ik leg het uit. Het begon gisterasvond toen collega blogger Jan Brandt mij tipte dat er op Nederland 2, eh…. NPO 2 heet dat tegenwoordig, een aflevering zou komen van het programma…

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Will The Large Hadron Collider ‘Break’ The Standard Model?

“Many physicists are excited about the possibilities while others are more pessimistic. However, the most important aspect of this is that everyone is appropriately cautious, practicing responsible science instead of prematurely declaring a new discovery. There are many hints of new physics out there, but we cannot be sure which ones will hold up and which ones will turn out to be mere statistical flukes. The only way forward is to take as much data as we can and to examine the full, synthesized suite of all of it. The only way we’ll ever reveal the secrets of nature is to put the question to the Universe itself, and listen to whatever it is that it says. With every new collision we create in our detectors, the closer we get to that inevitable but critical moment that physicists all over the world are awaiting.”

I don’t know whether you should bet on the discovery of new physics or whether you should bet against it, but I want to know what’s out there beyond the frontiers of what we know today. Perhaps this is nothing, but perhaps it’s also the first hint of something dazzling and novel about the Universe.

Is the LHC on the brink of discovering new physics?

Is the LHC on the brink of discovering new physics?

The latest announcement from CERN hints at the inadequacy of existing theories of elementary particles

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Ask Ethan: Could An Unexplained Decay At The LHC Demolish The Standard Model?

“I want know more about the last announcement from the LHCb [collaboration] about CP Violating asymmetry in a charged B meson decay. What [does] this mean and/or this is a hint for new physics beyond the Standard Model??”

I hear your whining all the time. “The LHC is such a waste. They haven’t found anything other than the Higgs.” Well, maybe you’re not paying attention to the right things, then? The Standard Model is so successful because it makes exquisite predictions for how the composite particles we produce in accelerators ought to live and decay. Well, we have a series of particles, the mesons that contain bottom quarks, that clearly aren’t obeying the rules of the Standard Model. The most robust puzzle we have about this is known as the Kπ puzzle, since there’s a large and significant difference between the CP-asymmetry of neutral and charged B-mesons that decay to kaons and pions.

Could this be the hint of new physics beyond the Standard Model we’ve waited for for so long? Don’t count the LHC out yet, and keep looking for new anomalies!

The Standard Model Is Not Enough, New LHC Study Shows

“It’s vital, as the LHC currently undergoes its high-luminosity upgrade and the world agonizes over whether to build a new, more powerful collider, to remember what’s at stake. We’re trying to understand the most fundamental components of our Universe: how they behave, what they are, and where they come from. The way we do that is through direct experimental tests. While on the one hand, we know the Universe must have gotten its matter somehow (just as it must’ve gotten its dark matter, somehow), the other hand has yet to reveal exactly where it came from.

The Standard Model continues to be mind-bogglingly successful at predicting what the full suite of these experiments should deliver, but has so far failed to reveal a hint as to how these big mysteries might be resolved. We know the Standard Model can’t be all there is to the Universe, but it works so thoroughly well with each test we throw at it. Each piece of new data we collect is a chance to stumble upon the place where it finally breaks down; an incremental step towards an inevitable revolution. The only question is whether we’ll give up before we get there.”

The best-ever measurement of how quarks mix together, from a single analysis, was just published by the LHCb collaboration at the Large Hadron Collider. Everything it measured is consistent with every other particle physics experiment that’s ever been performed, and with the Standard Model as well.

The only problem? It doesn’t tell us where the matter in our Universe comes from: normal or dark. The greatest mystery of all deepens, still.

Researchers discover CP violation in charm meson decays

Researchers from the Higher School of Economics and Yandex, as part of the LHCb collaboration at CERN, have been the first to discover CP violation in charm meson decays. On March 21, representatives of the LHCb collaboration spoke about this recent breakthrough at the Conference on Electroweak Interactions and Unified Theories in La Thuile.

This discovery may become a key to solving the mystery of matter-antimatter asymmetry in the universe.

One of the unsolved problems in physics concerns the abundance of matter over antimatter in the universe. During the first split seconds after the Big Bang, matter and antimatter appeared in equal shares. Today, the observed quantity of antimatter in the universe around us is negligibly small. The physicists are trying to understand where it has gone. According to Soviet academician Andrey Sakharov’s hypothesis from 1967, the matter-antimatter imbalance could have evolved as a result of CP invariance violation (particle-antiparticle symmetry).

In 1973, Makoto Kobayashi and Toshihide Maskawa proposed that a natural explanation for CP violation effect. According to the Kobayashi-Maskawa theory, in the Standard Model of fundamental interaction, CP violation happens through a single phase. However, the manifestation of this effect in the decay of particles containing various heavy quarks strongly depends on the other features of the Standard Model of elementary particles. CP violation in charm D meson decays was expected to come to around 0.1-0.01%.

The LHCb (Large Hadron Collider beauty) experiment was carried out at CERN to study B mesons, unstable particles, in the decay of which the matter-antimatter asymmetry manifests particularly well. Scholars analyzed the data received in an LHCb experiment in 2011-2018 and found that the total number of decays of anti-D0 mesons exceeded the total number of decays of D0 mesons. The result has a statistical significance of 5.3 standard deviations, exceeding the threshold of five standard deviations used by particle physicists to claim a discovery.

‘Studying CP violation is extremely important for understanding the mechanisms of our universe’s evolution,’ explained Denis Derkach, Senior Research Fellow at the Faculty of Computer Science Laboratory of Methods for Big Data Analysis (LAMBDA), adding: 'The discovery of CP violation in charm meson decays is a big step in the study of this phenomenon in heavy meson decays’.

Furthermore, researchers from HSE and Yandex School of Data Analysis applied AI tools in the study, which improved the quality of LHCb experiment data selection and analysis. Yandex’s computation capacities have also been used to model the LHCb experiment events, which is essential for correct interpretation of the physical results.

'Thanks to our team efforts, the effectiveness of the trigger used to select significant events was increased by 40% on average,’ said Fedor Ratnikov, Senior Research Fellow at LAMBDA Laboratory. He noted: 'With the use of neural network Bayesian approaches, we have improved the algorithm for detecting the type of particles observed by the detector.

We have also developed a “smart” system for quality monitoring of detector operations’.

No, Physicists Still Don’t Know Why Matter (And Not Antimatter) Dominates Our Universe

“According to the hot Big Bang, the Universe as we know it today was born 13.8 billion years ago, and was filled with energy in the form of photons, particles, and antiparticles. The Universe was hot, dense, and expanding extremely rapidly under those early conditions, which caused the Universe to cool. By the time less than a single second had passed, practically all of the antimatter had annihilated away, leaving approximately 1 proton and 1 electron for every 1 billion photons.

The Universe was thought to be born matter-antimatter symmetric, as the laws of physics dictate. But something must have happened during that first fraction-of-a-second to preferentially create matter and/or destroy antimatter, leaving an overall imbalance. By the time we get to today, only the matter survives.”

In a really cool experiment at CERN, enormous numbers of particles called mesons, containing one quark and one antiquark, are produced and studied. Some of those particles contained charm quarks, while others contained charm antiquarks. When they decayed, there was a slight difference in the ratios of what their decay products were, indicating a fundamental asymmetry between matter and antimatter.

But this was already seen in both strange quark and bottom quark systems, and doesn’t explain our Universe’s matter-antimatter asymmetry. Get the full story here.

Today afternoon we will be at Nikhef, the national institute for subatomic physics. Most of us will reach the Amsterdam science park by bike with Ed.

CERN’s LHCb detector blijft een anomalie zien in het B° → K∗° µ+ µ− verval!

We hadden het er in 2015 al uitgebreid over: de door de LHCb detector, verbonden aan ‘s werelds grootste deeltjesdetector de Large Hadron Collider (LHC) van CERN bij Genève, gevonden B°→K*°μμ anomalie. Toen zaten de natuurkundigen nog in Run 1, die bij 7 TeV protonen tegen elkaar liet botsen. Nu hebben we Run 2 achter de rug, waarbij de botsingsenergie is opgeschroefd naar 13 TeV, en wat blijkt:…

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Another morning full of nice images thanks to the LHCb team that is in charge of the scintillating fibre that will be the main component of the new LHCb detector. They will will make up the new SciFi tracker, which will replace the outer and inner trackers of the LHCb detector as part of the experiment’s major upgrade during Long Shutdown 2 (LS2).

After the recording, as usual, selfie. Thanks for your help!

The LHCb experiment investigates the slight differences between properties of matter and antimatter by studying a type of particle containing the “beauty quark” (or “b quark”). The LHCb Experiment at CERN will shed light on why we live in a universe that appears to be composed almost entirely of matter, but no antimatter.

@CERN

Yandex has developed a new method of machine learning called CatBoost. It allows you to efficiently train models in line with heterogeneous data - such as user location, operation history and device type. The library of computer training CatBoost is released in public access, it can be used by all comers.
To work with CatBoost, it’s enough to install it on your computer. The library supports Linux, Windows and macOS operating systems and is available in Python and R programming languages. Yandex has also developed a CatBoost Viewer visualization program that allows you to monitor the learning process on the charts. You can download CatBoost and CatBoost Viewer on GitHub.

CatBoost is the heir of the Matrixnet machine learning method, which is used in almost all Yandex services. Like Matrixnet, CatBoost employs the mechanism of gradient boosting: it is well suited for working with heterogeneous data. But whereas Matrixnet teaches models on numerical data, CatBoost also takes into account the non-numerical ones, for example cloud types or types of buildings. Previously, such data had to be translated into the language of figures, which could change their essence and affect the accuracy of the model. Now they can be used in their original form. Thanks to this, CatBoost shows a higher quality of training than similar methods for working with heterogeneous data. It can be used in a variety of areas - from the banking sector to industrial needs.

Mikhail Bilenko, head of the of Yandex machine intelligence and research department:

“Yandex has been engaged in machine training for many years, and CatBoost was created by the best specialists in this field. By releasing the library CatBoost in open access, we want to contribute to the development of machine learning. I must say that CatBoost is the first Russian method of machine learning, which became available in the open source. We hope that the community of experts will appreciate it and will help to do even better.”

The new method has already been tested on Yandex services. As part of the experiment, it was used to improve search results, to rank the Yandex.Den recommendations tape and to calculate the weather forecast in Meteum technology - and in all cases proved to be better than Matrixnet. In the future, CatBoost will work on other services. It is also used by the Yandex Data Factory team - for their solutions for the industry, in particular for optimizing raw material consumption and predicting defects.

In addition, CatBoost was implemented by the European Center for Nuclear Research (CERN): they are using it to combine data obtained from different parts of the LHCb detector.