Tag Archives: Higgs

Higgs Search At LHC Nears End – Has The Higgs Already Been Found?

The Higgs Boson may have finally have been caught or, may be, not! Only a clutch of scientists with direct access to latest LHC data knows whether the Higgs has been found or not! Whatever the result be, one thing is for sure the Higgs hunt is nearly over. CERN researchers have restricted the Higgs mass to a window of only 30 GeV, taking into results from the Large Electron Positron (LEP) collider, the Tevatron and, of course, from the LHC itself.

A simulated Higgs event at LHC

The Higgs, if present in Nature, has got extremely little energy space to hide in. At a conference in Paris, held today (18th November), ATLAS and CMS researchers got together and erased out a HUGE range for the possible mass of the Higgs. A large swathe from 141 to 476 GeV was wiped out in one fell swoop. Says Guido Tonelli, the spokesman for CMS

We’ll know the outcome within weeks.

This is surely going to increase the pulse rate of any particle physicist in the world.

The mass range as it looks now (Courtesy: Nature)

What if…

What happens if the Higgs is not found? A lot of problems for the Standard Model. The Higgs boson is the simplest way to generate masses for fermions (like electrons and protons) and bosons (like W and Z bosons). There are other possibilities, but this one Higgs model is the simplest and most beautiful of all the possible models. However, as Feynman would say, if theory disagrees with experiment, then it’s wrong and it doesn’t matter how beautiful the theory might be.

For long, has the Higgs mass been pinned at about 140 GeV. There is still a strong possibility that the Higgs, if found, will be of this mass. We may be on the brink of history.

More Info:  http://www.nature.com/news/higgs-hunt-enters-endgame-1.9399

Get The LHC On Your Android Phone, Thanks to Oxford University

Now, you can participate in the unraveling of the greatest mysteries ever on your Android phone. Oxford University has come up with a Large Hadron Collider (LHC) app for Android mobiles. The app is nicely named LHSee’ and gives the user a nice chance to explore the Large Hadron Collider in full 3D glory and detail. You can download the app here.

So, the Higgs Boson particle is still elusive and the LHC is hot in pursuit of the mysterious Boson. Not that you can do much about that sitting at home (or maybe you can donate you’re your computer’s processing power to CERN), but you can certainly get a sense of what is going on at the LHC on a regular basis.

Not as easy as Angry Birds

The bad news is that the details are really involved and you’ll probably take some time to take in everything. The Oxford bundle comes with a host of educational resources, besides the simulation. You’ll be able to learn more about ATLAS, one of the premier detectors at the LHC. It even has a game Hunt the Higgs, which we hope will become as popular as Angry Birds. So, while the LHC is busy colliding protons at monumental energies, you’ll be challenged with picking up the different proton-proton collisions from the jumbled mess. If you spot the Higgs, do give yourself a pat on the back.

Check out the official Oxford University site here:  http://www2.physics.ox.ac.uk/about-us/outreach/public/lhsee

CERN’s huge LHC now comes in your phone. That’s another reason for a physicist to buy an Android phone, if you don’t already have one.  The biggest search in the history of humanity now occurs on your phone. Feel proud about that! High energy physics has never been this much fun!

Download link from Android market again:  https://market.android.com/details?id=com.lhsee

New Physics Should Be Around The Corner, Says Rolf Heuer, Director of CERN; Charts Future After LHC

It was just yesterday, yet we have come so far! The first proton beams at a respectable 7 TeV energy was started only on 30th March, 2010. It has been hardly a year and a half and so much has already been achieved. This was the basic message sent out by CERN speakers Frederick Bordry and Rolf Heuer, also the Director of CERN at the Lepton Photon Conference, 2011, being held at Tata Institute of Fundamental Research, Mumbai, India.

Projects! Projects!

There are a lot of projects on the horizon, both short time and long time. Obviously, the long term projects are ambitious and a bit ambiguous as of now. However, as Heuer said, they are practical. We should not be afraid that it is not easy, he said.

Rolf Heuer, Director General of CERN, speaking at the Lepton Photon Conference, 2011, at TIFR, Mumbai

Among the many new developments happening or proposed at LHC is the development of magnets that can generate extremely high magnetic fields, called high-field magnets. These will be required to increase the energy of a beam, without lengthening the collider tunnel. Prof. Michael Peskin of SLAC, who was in the audience, asked if this is a dream or a programamidst chuckles, to which Bordry replied that it was certainly a realistic program.

The CMS detector at LHC

The LHC is expected to have a long shutdown period from 2013 to mid 2014 for repairs and maintenance work.

New physics and monster accelerators

A number of new projects are upcoming, even though they haven’t been officially sanctioned. Yesterday’ it was the synergy of the Tevatron, HERA and SLAC that led to the discovery of the Standard Model, said Heuer, adding that the LHC results will guide the way at the energy frontier.

About the Higgs search, Heuer said that while finding the Higgs will be a discovery, not finding the Higgs and ruling it out will also be a major discovery. People should not say that these scientists are searching for nothing, he quipped. Not finding the Higgs will be a major result, since it will completely destroy the Standard Model, allowing other models of physics to come into the limelight.

Among a plethora of futuristic plans announced, the most spectacular was the announcement of a hadron-lepton collider the LHeC. The LHC is a hadron-hadron collider. It can collide protons together or lead/silver nuclei etc. A hadron-lepton collider will be able to collide a proton, and say an electron. The energy per beam of the LHeC will be 16.5 TeV, combining to give a massive 33 TeV in total. The LHeC design is on my desk right now, but I shouldn’t be mentioning that here, he remarked drawing loud laughter from the global audience. As far as LHC physics is concerned, he said that 2012 will be a decisive year. The TeV results will either lead to the discovery of new particles and some new physics will be known or it will be a reformulation of the physics we already know. Both will be progressive steps for particle physics.

Heuer spoke at length on the building of the linear accelerators International Linear Collider (ILC) and the Compact LInear Collider (CLIC). Today, we need to keep our choices openwas Heuer’s advice.

International Collaboration

On the question of collaboration, Heuer said that CERN was throwing its doors open to non-European countries. The E’ in CERN is going from European’ to Everybody’. We’re not changing our name, however, said Heuer.

Exciting times in particle physics beckon us! As usual this sentiment was put emphatically in Heuer’s own words -We are just beginning to explore 95% of the universe.

I’ll let the scientist in Heuer have the final word on this report. When asked if he’ll be bothered if the next big accelerator is located in the US, instead of at CERN, Heuer put it beautifully, I don’t care where the collider is! I only care about the science coming out of it.

The scientific enterprise is a greater binding factor than anything else. It’s a silent messenger of world peace, uniting the world in the pursuit of truth and never advertising that facet.

High Energy for Dummies: A Brief Glossary of Technical Jargon Used in Particle Physics

If a high energy collision means fast billiard balls colliding or a train wreck, this article is tailor made for you. As the world, or at least the 0.042% of it who are interested in particle physics, gets their opinions ready about the yet unsuccessful Higgs search at the Large Hadron Collider (LHC), CERN, we thought it might be a good idea to explain what physicists mean by what they say. However, we don’t want to explain why they speak that way.

Tunnel of the LHC

Here we will list out a few things you’ve heard and are likely to hear in the coming days, along with what they might possibly mean.

Units and Particles:

Energy units

In particle physics, people prefer to use units of energy, instead of that of mass to measure mass. The idea is a good one, since we can use Einstein’s relation E=mc2 directly. The unit of energy is an electron volt or eV. If you force an electron to go through one volt, then it has the energy of 1 eV. It’s too small to use, so people use 1Mega eV (MeV) 1 million eV, or 1Giga eV (GeV) 1 billion eV. If that is not large enough, the LHC demands that we use 1 Tera eV (TeV) or 1 million million eV. The LHC is currently operating at 7 TeV.

The more important point to note about energy is what is considered big! How much really is 1 TeV of energy in human scales? It’s much less than the kinetic energy of a house-fly! So why is it called high-energy physics? It’s because this energy is carried by particles that are really really small! If a proton having 3 TeV of energy is scaled up to our scales, then we would each have energy exceeding that of a Supersonic jet plane. There’s a large amount of energy packed into a small volume.

Particles types

About particles, there are just two types Fermions and Bosons. Know that fermions don’t like hanging out together, while bosons have no such ego issues. You can stuff a lot of bosons at one place, while that is impossible in case of fermions. Leptons are one kind of fermions, which are electron-like. Photons are bosons. (As to why this happens, it’s related to the Pauli Exclusion Principle, a fundamental result from quantum mechanics, responsible for single-handedly creating all of chemistry! Fermions follow Pauli Principle, bosons do not).

Hullabaloo about Higgs:

This is the biggest name in particle physics you’ve ever heard. The electron is passé, it’s time for the Higgs. Named after Peter Higgs, this particle is supposed to endow all other particles in the Universe with mass. It is a so-called boson, unlike the electron. It is itself massive (meaning that it has mass), theoretically predicted to be about 140 GeV. Through a mechanism, known as the Higgs mechanism, an example of spontaneous symmetry breaking (explanation below) of a field theory, mass is generated.

Spontaneous Symmetry breaking:

This is probably the most important phenomenon in this story, so pay attention. This is the deal. Every modern physical theory has some symmetry associated with it. For example, if you made all the positive charges in the Universe negative and the negative charges positive, the Universe will still look exactly like it does. Here’s the crucial part with every (continuous) symmetry, is associated a quantity that is conserved, or doesn’t change value. Example: Take time translation. If time were to flow backwards, at the microscopic scale, we would notice nothing. This symmetry leads to conservation of energy. Symmetry breaking refers to the fact that under certain circumstances, a physical theory loses the symmetry it started out with. We can then distinguish between different states. We can choose.

A Useful Analogy

The best analogy I’ve heard asks you to picture a round table with 10 people sitting equally spaced from each other. There is one glass of water kept identically placed between each two adjacent persons, making it 10 glasses in total. Assuming that the glasses are all identical, one can go and reach out for either one there is no preferred choice as yet. (Situation 1 in the graphic below.) But, say someone does pick up a glass say the glass placed to his/her right.(Situation 2 in the graphic below.) Then, everybody will HAVE to pick the glass to his/her right (assuming that no one wants chaos!). Now, you can differentiate between this system and another such system in which someone went for the glass on the left. Symmetry breaking has allowed us to identify a parameter, which had earlier left the system invariant. The word spontaneous’ is clear from this context. The perturbation has to come from within the system and everyone will choose a glass. The symmetry has been spontaneously broken!

In physics too, there arises situations in which the ground state (or state of lowest energy) of a theory is invariant under certain symmetries. This symmetry can, however, be broken and spontaneously, too if the system interacts with a field. It can be shown that this leads to two distinguishable states one having mass. Physicist believe that this is how mass is generated. The interaction field is named Higgs field’ and the force carrying boson associated with the field (as with any force field) is the Higgs Boson.

Final Word

We could like to conclude this brief glossary of explanations here. Know that these explanations are highly simplified and the whole picture is much richer in beauty and technical details than this. Unfortunately, I won’t be able to communicate that beauty to a person, not having enough background in physics (being a major in physics is a must) and maths. If you already have a background, you’ve probably already seen a bit of the beauty. Go in search of more.

The world is not only queerer than we suppose, remember; it is much queerer than we can possibly suppose. In the words of the immortal Richard Feynman, I think Nature’s imagination is so much greater than Man’s, She’s never going to let us relax.

Links to related articles:

The Higgs search being unsuccessful so far, ATLAS and CMS collaborations of CERN jointly announce. Initial report here.

The figures and numbers (statistics) from the CERN announcement here.

Latest Results of Higgs Search Presented Jointly By ATLAS and CMS, LHC, CERN at Lepton Photon ’11, Mumbai

The latest results on the Higgs search are out. Results were presented separately by ATLAS and CMS detectors of LHC, CERN today(i.e. 22st August, 2011) at the Lepton-Photon Conference, 2011. In this semi-technical article, we present the most important results in a systematic form. The verdict is, however, out the Higgs hasn’t been found as yet.

Check out our first (non-technical) post on this discovery here. A countdown to the Lepton Photon Conference itself is here.

Higgs Production and Decay channels

There are a few things that should be kept in mind right throughout the article. The Higgs boson is primarily produced by interaction of two gluons. (A gluon is what keeps protons and neutrons in an atomic nucleus together.) This is called gluon-gluon production of the Higgs boson.

Next, the Higgs, being highly massive (i.e. having a high mass) decays into lighter particles. This is what massive particles always do they decay into lighter particles. The only thing is that different particles decay at different rates. Heavier particles will decay much faster than comparatively lighter particles.

Higgs event

The Higgs can decay into a number of lighter products. Each of these products leaves a distinctive signature on the detectors and the different modes of decay are called different decay channels’. The Higgs primarily has a gamma-gamma (Higgs decaying into two gamma ray photons.) channel, a WW and a ZZ channel. These are the main channels of interest. The gamma-gamma channel will be the preferred channel if the Higgs is a comparatively light particle about 100 GeV in mass. If the Higgs decays by producing two Z-bosons (the ZZ channel) or two W-bosons (WW channel) then its mass is above 130 GeV.   In other words, the gamma-gamma channel fixes the upper limit of the Higgs mass at 130 GeV, while the WW and ZZ channels fix the lower energy bound at 130 GeV.

Now, here is the interesting part. The WW or ZZ bosons are themselves quite heavy and decay into a number of products. These decay channels produce characteristic detection patterns in the detectors. Comparing the observed rate of decay into these channels with that of the expected value, the data is reconstructed to see if this indeed was a Higgs event.

Now for more technical details

ATLAS Results

The ATLAS detector found no significant excess in the gamma-gamma channel. The bottom-bottombar (b-bbar) channel (this is what the WW bosons break down into bottom and anti-bottom quarks) gave big excess of Higgs event above the theoretically expected Standard Model(SM) production rates. Even though the excess was nearly 10 times the SM predictions, the sensitivity needs to be improved. Furthermore, Tevatron has a much greater say in the b-bbar channel than the LHC, given that it has recorded much higher number of events and has a higher luminosity at that energy range. The tau-tau (tau is a lepton, an electron like particle) channel gave a 4 to 5 times excess.

The ATLAS detector at LHC, CERN

Overall, there was no significant excess in any of the channels to warrant a discovery. There was no significant excess number of events noticed for the Higgs in the mass range of 110 GeV to 160 GeV. This mass range is tentatively excluded with 95% confidence level. However, at 99% confidence level, there is a window about 142 GeV, which can be a possible detection window. Further experiments will probe this window more thoroughly.

CMS results

CMS detected no excess in the gamma-gamma channel. A slight excess was noticed in the tau-tau channel and this is expected to be an important channel for further investigation, owing to the fact that data reconstruction from this channel points to a Higgs mass of about 140 GeV.

Excess of events in the WW going to lepton-lepton channel suggests a mass range of 130 GeV to 200 GeV. Three pairs of events have been notices at three mass ranges 122, 142 and 165 GeV for the ZZ channel. Only the 142 GeV event is consistent with Standard Model predictions. Happily, this is the very window that wasn’t excluded earlier with 99% confidence level.

Out of theoretically expected mass range exclusion of 145 to 440 GeV, three ranges have been excluded 145 to 216 GeV, 226 to 288 GeV and 310 to 400 GeV. Anything above 400 GeV is unlikely and the crucial 130 to 145 GeV window is still open. These mass ranges have been excluded with 98% confidence level.

Higgs search continues with full force. LHC will provide a lot more data samples in the coming months and this might ultimately lead us to achieve the Holy Grail of Particle Physics.

Higgs Boson Still Not Found: Huge Official Announcement from LHC, CERN

HIGGS SEARCH RETURNS A BLANK! HIGGS BOSON NOT FOUND BY LHC, CERN!

This is the joint announcement made by the ATLAS and CMS teams, LHC, CERN at the Lepton-Photon Conference, 2011 being held at Tata Institute of Fundamental Research (TIFR), Mumbai, India. This is likely to be a disappointment for many around the world, both within and without the particle physics community. The search is however on!

A warmup countdown post to this Lepton Photon Conference, 2011 is here. Semi-technical post showing all relevant results and figures can be found here.

The Higgs Boson

The Higgs Boson, predicted from considerations of symmetry in Quantum Field Theory by Peter Higgs, is the particle theoretically responsible for endowing every other massive particle with mass. It’s a boson with spin zero, with positive parity and charge.

Weak Signals

There were a number of weak signals noticed that preceded the event. These Higgs signatures’ included the W-W or the Z-Z decay channel for the Higgs as the primary decay channel. This means that the Higgs once produced will decay into two W or Z-bosons, which will in turn break up into electron-positron pairs or muon-antimuon pairs. Unfortunately, none of these events could stand up to the rigors of analysis and survive till the 5 sigma confidence level was reached in both ATLAS and CMS detectors, as yet.

No such significant excess has been observed in the lower mass gamma-gamma channel. Also, more exotic branches like the tau-tau and b-bbar (bottom-bottombar quarks) have not offered anything promising.

The results of Tevatron, Fermilab are similarly blank, with no significant excess noticed in any channel.

The Future

This is also an exciting opportunity it opens up new possible physical theories. Spontaneous symmetry breaking, at least what we know of it now, may not be the whole story. There are many rival’ theories of the Standard Model, many requiring no Higgs boson to achieve mass. These Higgless models may become the focus of mainstream research and the LHC may be next used to test the predictions of such theories.

However, it is too early to make such claims. The Higgs search is going on at full blast.

And a Promise

We will bring more articles soon, explaining what this means for the Standard Model and particle physics in general. We will also run an article elucidating the jargon of particle physics. Hold on for that it’ll come sooner that you think.

Update

Actual results from the ATLAS and CMS joint announcement on the Higgs Boson search can be found here. All relevant facts and figures present.

Countdown to Lepton-Photon Conference, 2011: ATLAS To Make Major Announcement on Higgs Search

Some big news is just around the corner. The ATLAS collaboration at LHC, CERN is all set to announce the status of the Higgs Boson search at the giant collider in the upcoming week at the Lepton-Photon Conference 2011, being held in Mumbai from 22-27 August, 2011. The announcement is one of particular importance since it is rumored to be the definitive one in the quest for the Higgs Boson. Whether the Standard Model of Physics, one of the most beautiful and successful edifices of physics ever constructed, will stand or need revision will hinge crucially on this one announcement.

The Lepton Photon 2011 Logo

The Lepton-Photon Conference, 2011

The Conference The XXV International Symposium on Lepton-Photon Interactions at High Energy will take place in Tata Institute of Fundamental Research, Mumbai, India and will attract prominent personalities from the world of high-energy physics. The coming week is expected to be a hectic one for both students and physicists at the Institute, with the who’s who of particle physics presenting and discussing current progress, while also charting the road ahead. Preparations are on at full swing within the Institute premises.

We at Techie-Buzz will be covering the huge scientific event from Ground Zero and presenting all the major announcements in real time from it.  You might want to bookmark the website and visit it frequently or subscribe to our newsletter, if you aren’t already on the subscription list.

Some exciting developments precede the event

The watch-word is Higgs’ for everyone and with certain encouraging signs noticed in the last few months, everyone is excited. Particularly stunning are the two results graphed below. Explanations follow the graphs.

The CMS (above) and ATLAS (below) Results for Higgs event, July, 2011

Look at the two graphs (don’t get scared!). The thick black line in each graph represents the Higgs signals. The dashed line represents the predicted Higgs production rate by Standard Model Calculations. A proper signature is said to be found when the observed signal overtakes the predicted signal. Look at the region marked, just between 130 to 150 MeV, where the production rate far exceeds the predicted rate. This coincides with the predicted mass range for the Higgs. This in itself proves nothing, as this might be due to something completely different. What is exciting is the fact that this weaksignal is being noticed in both the LHC detectors, ALICE and CMS. Concurrent results have a better chance of surviving thorough data analysis.

For clarity let me reiterate the two important takeaway points: First, both detectors, ATLAS and CMS, agree on the Higgs signature. Second, the signals have been noticed in the theoretically expected mass range (about 130-150 GeV).

The results are now quoted at a 95% confidence level (or 2 sigma) and do not warrant the label of a discovery’. For that, you’ll require 99.997% confidence (or 5 sigma) from both detectors. We might be onto that.

At the risk of being repetitive, let me again emphasize that the announcement at the Conference in the coming week will nearly finalise the fate of the search for the Higgs Boson. If not found, it may be the beginning of new physics.

Hope to see you here through next week.

Update: The CERN Announcement on the ATLAS and CMS results on the Higgs Search is here. Check it out, its big news.

News from LHC, CERN: CMS Results Rule Out Large Mass Range for Higgs Boson Particle

Last year’s run of the LHC has set a cutoff for the expected mass of the Higgs boson. This important result came out of the recently concluded Europhysics Conference 2011.

CMS has excluded the mass ranges of 149-206 GeV and 300-440 GeV for the Higgs with a confidence level of 95%. It has also excluded the masses from 145-480 GeV with a lower confidence level of 90%. This excludes a huge part of the expected mass range, and has gotten particle physicists both excited and demoralised.

Read about the Quark Conference 2011 here, rumour of a Higgs being detected at ATLAS, LHC, CERN here and that news being rejected here. We covered a very recent discovery by Fermilab  here.

The Higgs Boson, also called ‘God Particle’ is the only particle predicted by the Standard Model but has not been detected in any collider. It has been assigned the function of endowing all particles in the Universe with mass. Any particle interacting with the Higgs field, mediated by the Higgs boson, is said to have mass. The boson is named after physicist Peter Higgs, the person who came up with the idea. Unfortunately, the Standard Model says little more than the lower limit of the mass of the Higgs Boson. CERN has given itself till 2012 for proving the existence of the Higgs.

Higgs Event

Further news is that is the results of the 2010 and 2011 runs are interpreted in the light of a Standard Model having four generation of fermions (SM4), instead of just three, scientists put a 95% confidence level on the exclusion of the Higgs boson in the mass range of 120-600 GeV.

There are also many particle physics theories not involving any Higgs boson called Higgless theories and they may now come to the forefront, if the Higgs remains elusive.

CMS is carrying on the search using decays of different particles. It is trying to produce the Higgs using two photons, two tau leptons, two W bosons and two Z bosons.

Eureka Moment Claims Rejected: No New Particle Discovered At Fermilab

It is disappointing news for the particle physics community coming out of Fermilab, we’re afraid. Fermilab has confirmed that the earlier bump seen in the data, presumed to be a new particle, is not significant enough to be considered a detection. We broke the news in emphatic fashion of a new particle discovered in Fermilab in an earlier post.

Story So Far

We had reported that there was a bump found at about 145 GeV with a 5 GeV spread. Data acquired from proton-antiproton collisions with semi-leptonic dijet emissions showed a peak at 145 GeV. The curve was Gaussian in nature with a spread of 5 GeV on either side of the peak. Initial analysis showed that the curve had a three-sigma confidence level (More on confidence levels later). There was thus a strong possibility that a new particle was on the way, since no boson is known having a mass of 145 GeV. The new particle was named as the Z’ or the W’ (Z-primed or W-primed) boson. The Standard Model, wildly successful in particle physics, did not predict this and to fit this in would have required a serious rethinking of known physics. Physicists were naturally excited.

This detection was made at Fermilab at their CDF detector.

The CDF detector

Fermilab was the biggest particle accelerator till the Large Hadron Collider came onto the scene. It has been a major progressive force for particle physics over the last three decades, also serving to etch the American superiority in the particle physics arena. It is however expected to be closed down forever late this year. Data recovered from it over the years is still being analysed, and as such will continue for the next five years. One of the two detectors at Fermilab the CDF had detected the anomalous bump of our present interest.

So What’s Wrong?

There are two problems with the CDF data it cannot be corroborated and it falls outside the required confidence levels.

Problem 1:

The DZero Detector

The other detector at Fermilab, named DZero, repeated the experiment, but failed to come up with any conclusive evidence of detection. The negative DZero result would definitely cast shadows over the CDF discovery. Scientists are now baffled as to how the two detectors extremely alike could give such widely varying results under the same experimental conditions. However this is a very good safeguard.

 

Problem 2: Remember that earlier we had said something about a three-sigma confidence level? It means that the data is reliable and the chances of it being wrong are one-in-a-thousand (99.9% accurate). Confidence levels measure reliability of data. For a discovery to be accepted by the scientific community, the event must have at least a five-sigma confidence level or higher, which means that doubts must reduce to less than one-in-a-million. The problem with the current bump is that it lies just below the five-sigma confidence level.

Graph for the DZero Results.

Take a look at the above graph. Never mind the mathematics and abstruse symbols. Know that the horizontal axis represents the mass of the particles and the vertical axis represents the number of particles detected. At the 145-150 GeV range (point 145 GeV on the horizontal axis), you’d have expected a curve if the previous CDF results were replicated. This is marked with the dotted curve. There is nothing there as far as DZero is concerned. The red regions represent detections and these are in complete agreement with the Standard Model. There is no anomaly to be seen anywhere.

On both counts, the bump is rejected as a new discovery.

What changes then?

Practically nothing changes. The 145 GeV particle, if discovered, would have been interesting, as the Standard Model doesn’t predict it. Further, it could have provided a mechanism for particles acquiring mass without the need of the Higgs boson (essentially becoming the new God particle’). With it being ruled out, the Standard Model stands as it is with the Higgs mechanism being the most favoured mechanism for mass generation.

The discovery would have been exciting, but the field’s exciting even without it. After all, science is like this. DZero spokesperson Stefan Soldner-Rembold  put it approproiately in a Fermilab press conference:

This is exactly how science works. Independent verification of any new observation is the key principle of scientific research.

So very true!

The “God Particle”: Higgs Boson Mystery Might Be Solved by 2012, Says CERN

The mystery of the Higgs boson, the so called God Particle, will be solved by 2012. This claim came from CERN a couple of days back. CERN spokesperson, Fabiola Gianotti, said:

By the end of 2012 we will either discover the Standard Model Higgs Boson, if it exists, or we will rule it out

Make or (almost) break:

This has caused quite a bit of excitement in the physics quarters, with people betting both ways, but leaning towards a successful search. The Higgs boson is supposed to endow all particles in the universe with mass. The mass of a particle depends on the strength of interaction with the Higgs field. Whereas a photon (particle of light) doesn’t interact with the field at all, an electron neutrino (a very light particle) interacts very weakly, while a proton (comparatively heavy) interacts much more strongly. The mechanism by which an interacting particle gets mass is called the Higgs mechanism, after the British physicist Peter Higgs, who first proposed it. Since then, the Higgs has been hot property in the particle physics arena, and has evoked strong interest outside it too. Probably, it is the most popular boson after the photon. The Higgs fits in nicely with the present Standard Model. The only problem is that it hasn’t been detected as yet.

A Simulated Higss event at LHC

If the Higgs boson were found, it would put an everlasting stamp of approval on the Standard Model. However, an unsuccessful search will not invalidate the Standard Model, as some people believe. There are many less known mechanisms not involving the Higgs, which describes how particles get mass.

The LHC:

The LHC was built with a primary aim of detecting the Higgs, especially with the Tevatron at Fermilab, the biggest collider before the LHC, shutting down in 2011. The enthusiasm to get at the Higgs is palpable within the science community and the desperation can be felt by the leakage of a memo at CERN a few days back. ATLAS, CERN has however invalidated the memo, which stated that a Higgs signature has been found.

The CMS Detector at the LHC, CERN

Smashing protons (and heavier nuclei) travelling at velocities close to that of light, scientists hope to recreate the conditions that supposedly existed right after the Big Bang. The LHC recently crossed the 7 TeV energy limit and also set a new record for beam intensity. This is, however, just half of its maximum capability. Scientists are busy acquiring and sifting through data of the order of terabytes, looking for a sign of the elusive Higgs and any of its heavier super-symmetric partners that the Standard Model predicts will have to exist, if the Higgs exists.

There will be an answer. Whether that answer will please Standard Model physicists is another question, and we will have to wait till 2012 for that.

Watch this space for more…