Independent measurement strengthens the case for toponium

Amazing stuff!

"An independent measurement by the CMS experiment at the LHC confirms the existence of toponium, a bound state of a top quark and its antiquark, with a statistical significance exceeding five standard deviations. This finding establishes toponium as the most massive composite particle observed and enhances understanding of the strong nuclear force."

"... The first hints of toponium appeared in searches for heavy Higgs-boson-like particles that could decay into a top quark–antiquark pair. An unexpected excess of collision events was observed at a mass close to twice the mass of the top quark, which is more characteristic of a bound state rather than a new fundamental particle. Detailed studies by the CMS and ATLAS experiments confirmed this excess using events in which both top quarks decay into leptons (electrons or muons).

The new CMS study approaches the problem from a different angle, examining events in which one top quark decays into a bottom quark, a charged lepton and a neutrino while the other decays into quarks that produce sprays, or "jets," of particles. ...

These new techniques proved highly effective. They resulted in the observation of an excess with a statistical significance of more than five standard deviations ... The result provides a new, statistically independent confirmation of toponium production.

"Toponium is heavier than the heaviest known atomic nucleus, oganesson, making it the most massive bound state ever observed," ..."

From the abstract:

"A search is presented for top quark-antiquark (t¯t) bound states near the t¯t

 production threshold, in final states with a single electron or muon and jets. The study uses proton-proton collision data at √s= 13 TeV, collected by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of 138 fb

−1. The analysis examines the relative velocity between the top quark and antiquark, along with two angular observables sensitive to the parity and spin of the t¯t system. A significant excess of events is observed relative to the standard model prediction for t¯t production calculated at next-to-next-to-leading order in perturbative quantum chromodynamics. The excess corresponds to an observed cross section of 5.1 ± 0.9pb and is consistent with a simplified model of a color-singlet pseudoscalar toponium motivated by nonrelativistic quantum chromodynamics. The result provides an independent confirmation of the excess reported in the dilepton channel."

Independent measurement strengthens the case for toponium

Observation of a pseudoscalar excess at the top quark pair production threshold in the single lepton channel (open access)

High-intensity bunches for the HL-LHC

Recommendable!

Top quarks pair up with their antimatter counterparts in a quasi-bound state called toponium

Amazing stuff! The scientists refer to their discovery as an "elusive dance". What were they smoking? Just kidding! 😊

"... For decades, physicists believed that the top quark, the heaviest known subatomic particle, was too short-lived to form a temporary pair with its antimatter partner. Unlike lighter quarks, which can combine to form protons, neutrons, or longer-lived quark–antiquark pairs, the top quark decays almost instantly. This made the idea of a top–antitop bound state – a fleeting association held together by the strong force – seem impossible. But now, the CMS collaboration at the Large Hadron Collider (LHC) has found the first evidence of such a state, which is dubbed toponium. ..."

"An unforeseen feature in proton-proton collisions previously observed by the CMS experiment at CERN’s Large Hadron Collider (LHC) has now been confirmed ... The result ... suggests that top quarks – the heaviest and shortest-lived of all the elementary particles – can momentarily pair up with their antimatter counterparts to produce a “quasi-bound-state” called toponium. 

Further input based on complex theoretical calculations of the strong nuclear force -- called quantum chromodynamics (QCD) -- will enable physicists to understand the true nature of this elusive dance. ...

Basing itself on a simplified toponium production hypothesis, CMS measured the cross section for the top quark–antiquark excess to be 8.8 picobarns (pb) with an uncertainty of about 1.3 pb. This passed the “five sigma” level of certainty required to claim a discovery in particle physics and made it extremely unlikely that the excess over the background-only prediction is just a statistical fluctuation.

“The observation of a non-relativistic QCD effect that was thought to be too difficult to detect is a great triumph for the LHC experiment programme,” ..."

From the abstract:

"A search for resonances in top quark pair () production in final states with two charged leptons and multiple jets is presented, based on proton–proton collision data collected by the CMS experiment at the CERN LHC at , corresponding to 138 fb−1.

The analysis explores the invariant mass of the  system and two angular observables that provide direct access to the correlation of top quark and antiquark spins.

A significant excess of events is observed near the kinematic  threshold compared to the non-resonant production predicted by fixed-order perturbative quantum chromodynamics (pQCD).

The observed enhancement is consistent with the production of a color-singlet pseudoscalar () quasi-bound toponium state, as predicted by non-relativistic quantum chromodynamics. Using a simplified model for  toponium, the cross section of the excess above the pQCD prediction is measured to be ."

Top quarks embrace in quasi-bound toponium – Physics World

Elusive romance of top-quark pairs observed at the LHC (original news release) "The CMS and ATLAS experiments at CERN’s Large Hadron Collider have observed an unforeseen feature in the behaviour of top quarks that suggests that these heaviest of all elementary particles form a fleeting union."

Observation of a pseudoscalar excess at the top quark pair production threshold (open access)

Detecting the conversion of lead into gold at the Large Hadron Collider of CERN

Has the ancient dream of alchemy finally coming true?

"... the ALICE collaboration reports measurements that quantify the transmutation of lead into gold in CERN's Large Hadron Collider (LHC). ..."

"In a paper published in Physical Review Journals, the ALICE collaboration reports measurements that quantify the transmutation of lead into gold in CERN’s Large Hadron Collider (LHC).

Transforming the base metal lead into the precious metal gold was a dream of medieval alchemists. This long-standing quest, known as chrysopoeia, may have been motivated by the observation that dull grey, relatively abundant lead is of a similar density to gold ...

Though gold has been artificially produced in this way before, the ALICE collaboration has now measured the transmutation of lead into gold by a new mechanism involving near-miss collisions between lead nuclei at the LHC.

Extremely high-energy collisions between lead nuclei at the LHC can create quark–gluon plasma, a hot and dense state of matter that is thought to have filled the universe around a millionth of a second after the Big Bang, giving rise to the matter we now know. ..."

From the abstract:

"The first measurements of proton emission accompanied by neutron emission in the electromagnetic dissociation (EMD) of 208 Pb nuclei in the ALICE experiment at the Large Hadron Collider are presented. The EMD protons and neutrons emitted at very forward rapidities are detected by the proton and neutron zero degree calorimeters of the ALICE experiment. The emission cross sections of zero, one, two, and three protons accompanied by at least one neutron were measured in ultraperipheral  208

 Pb −208 Pb collisions at a center-of-mass energy per nucleon pair √𝑠𝑁⁢𝑁=5.02TeV. The 0p and 3p cross sections are described by the RELDIS model within their measurement uncertainties, while the 1p and 2p cross sections are underestimated by the model by 17–25%. According to this model, these 0p, 1p, 2p, and 3p cross sections are associated, respectively, with the production of various isotopes of Pb, Tl, Hg, and Au in the EMD of  208 Pb. The cross sections of the emission of a single proton accompanied by the emission of one, two, or three neutrons in EMD were also measured. The data are significantly overestimated by the RELDIS model, which predicts that the (1p,1n), (1p,2n), and (1p,3n) cross sections are very similar to the cross sections for the production of the thallium isotopes  206,205,204 Tl ."

ALICE detects the conversion of lead into gold at the Large Hadron Collider

ALICE detects the conversion of lead into gold at the LHC (original news release) "Near-miss collisions between high-energy lead nuclei at the LHC generate intense electromagnetic fields that can knock out protons and transform lead into fleeting quantities of gold nuclei"

Proton emission in ultraperipheral Pb-Pb collisions at √𝑠𝑁⁢𝑁=5.02 TeV (open access)

A new piece in the matter-antimatter symmetry puzzle

Amazing stuff!

"Yesterday, at the annual Rencontres de Moriond conference taking place in La Thuile, Italy, the LHCb collaboration at CERN reported a new milestone in our understanding of the subtle yet profound differences between matter and antimatter. In its analysis of large quantities of data produced by the Large Hadron Collider, the international team found overwhelming evidence that particles known as baryons, such as the protons and neutrons that make up atomic nuclei, are subject to a mirror-like asymmetry in nature’s fundamental laws that causes matter and antimatter to behave differently. The discovery provides new ways to address why the elementary particles that make up matter fall into the neat patterns described by the Standard Model of particle physics, and to explore why matter apparently prevailed over antimatter after the Big Bang. ...."

From the abstract:

"The Standard Model of particle physics, the theory of particles and interactions at the smallest scale, predicts that matter and antimatter interact differently due to violation of the combined symmetry of charge conjugation (C) and parity (P). Charge conjugation transforms particles into their antimatter particles, while the parity transformation inverts spatial coordinates. This prediction applies to both mesons, which consist of a quark and an antiquark, and baryons, which are composed of three quarks.

However, despite having been discovered in various meson decays, CP violation has yet to be observed in baryons, the type of matter that makes up the observable Universe.

This article reports a study of the decay of the beauty baryon Λ0b to the pK−π+π− final state and its CP-conjugated process, using data collected by the LHCb (Large Hadron Collider beauty) experiment at CERN.

The results reveal significant asymmetries between the decay rates of the Λ0b baryon and its CP-conjugated antibaryon, marking the first observation of CP violation in baryon decays, thus demonstrating the different behaviour of baryons and antibaryons.

In the Standard Model, CP violation arises from the Cabibbo-Kobayashi-Maskawa mechanism, while new forces or particles beyond the Standard Model could provide additional contributions. This discovery opens a new path to search for physics beyond the Standard Model."

A new piece in the matter-antimatter puzzle | symmetry magazine

Observation of charge-parity symmetry breaking in baryon decays (open access)

Plans for a New gigantic atom-smasher in Europe, the LHC was not big enough

Bigger is better! 

Hint of crack in Standard Model of physics vanishes after revisiting of Large Hadron Collider data about 8 years later

To err is human! Scientists have seriously erred many times over history! 

Politically and ideologically motivated scientists spread and drive the Global Warming Hoax and Climate Change Religion propaganda and demagoguery!

This article is about a retraction! It took only 8 years to do it!

"A once-promising hint of new physics from the Large Hadron Collider (LHC), the world’s largest particle accelerator, has melted away, quashing one of physicists’ best hopes for a major discovery.

The apparent anomaly was an unexpected difference between the behaviour of electrons and that of their more-massive cousins, muons, when they arise from the decay of certain particles. ..."

Hint of crack in standard model vanishes in LHC data Discrepancy in measurement of a type of particle decay had raised hopes of new physics.

What’s new for Large Hadron Collider Run 3?

Recommendable! More details on the exciting new phase of the LHC!

What’s new for LHC Run 3? | symmetry magazine CERN’s accelerators and the LHC’s detectors have undergone major upgrades that will allow scientists to collect more data in the upcoming run than they did in the previous two runs combined.

Large hadron collider upgrade 'revolutionary'

Exciting stuff! Let the show begin! Will we soon witness new major discoveries? Will we for the first time detect dark matter?

Or how about the speculative fifth fundamental force?

The next subatomic particle supercollider

Recommendable! Good overview of current plans! Supercolliders are probably the most gigantic and most expensive research facilities on earth!

I found it surprising that the article did not mention any new such efforts in China, Russia, Brazil, or India.

The next supercollider | symmetry magazine What does it take to envision and build a seemingly impossible particle accelerator?

LHCb finds more matter-antimatter weirdness in B mesons

Recommendable! Amazing stuff!

"... Scientists on the LHCb experiment at the Large Hadron Collider study much more subtle differences between matter particles and their antimatter equivalents. A recent analysis allowed them to revisit an old mystery—an asymmetry between asymmetries. ...
Asymmetries are the reason we exist. CP violation—when mirror-image particles with equal and opposite charges do not have equal-and-opposite behavior—is the reason the universe was able to grow into more than the fizzing soup of particles that defined it after its birth 13 billion years ago. ...
studies particle collisions produced by the Large Hadron Collider. Parker and his colleagues are using these collisions to examine CP violation in B mesons, a phenomenon first observed ... in the early 2000s. Like kaons, B mesons contain a matter quark and an antimatter quark that oscillate between the two identities. LHCb scientists use their detector to capture the decay products of these flippant B mesons and reconstruct their final internal configurations. ...
While LHCb scientists saw a clear favoritism for one configuration in neutral B mesons, they also confirmed that the same favoritism does not exist for charged B mesons, an effect first seen at BaBar and Belle. LHCb’s result significantly strengthens this mysterious asymmetry of the asymmetries. ..."

LHCb finds more matter-antimatter weirdness in B mesons | symmetry magazine

Teasing Out The Difference Between Matter And Antimatter

Posted: 3/22/2019

Just read LHCb discovers matter-antimatter asymmetry in charm quarks (published 3/21/2019, Source 1; here is the underlying preprint research paper Observation of CP violation in charm decays (Source 2) published 3/21/2019).

This could, if confirmed, be a major breakthrough in physics and in our understanding of the universe! Are finally coming a little closer to explain the riddle that matter trumped over antimatter? It may result in rewriting theories and models!

“This is the first observation of CP [charge parity] violation in the decay of charm hadrons.”

If you are curious, here are most of the key terms associated with the research paper. They are really charming: “electroweak interaction ; flavor physics ; charm physics”. You have to kind of admire the poetry of physics!

Micro Black Holes Made In A Laboratory?

As a hobby science junkie I was absolutely stunned to read an article that scientists might be able to create such micro black holes using the Large Hadron Collider at CERN. According to this article such micro black holes at lower than expected energy levels through head-on collision of particles.

This article is a bit beyond my gray matter, but it seems mind blowing.