Use of English

a lot

Two words.

Note: See this enlightening cartoon on the subject.

grammar, spelling

a or an before H?

Use an before a silent H: an heir, an hour, an honest politician, an honorary consul; use a before an aspirated H: a hero, a hotel, a historian (but don't change a direct quote if the speaker says, for example, "an historic"). With abbreviations, be guided by pronunciation: an LSE student, a CERN student


abbreviations and acronyms

Do not use full points in abbreviations, or spaces between initials, including those in proper names:

US, eg, 4am, M&S, WE Weber, WH Smith, etc.


absolute zero

Not "the absolute zero".

-273.15°C or 0 K.

The apparatus was cooled to near absolute zero to ensure the electronics were in a superconducting state



Spell out the name at first mention, then abbreviate in brackets. Only use capital letters if it is the only machine with that name in the world.

This synchrocyclotron (SC) was built in 1957, whereas the Large Hadron Collider (LHC) was completed in 2009. The SC accelerates ions…



Include all accents in French, German, Portuguese, Spanish and Irish Gaelic words. But for words that have been assimilated into English (café, résumé) follow OED.

Note that capital letters in French also take an accent so état membre becomes État membre. 



For both sexes, never actress.


Administrative Circular

Follow the style dictated by the HR website, as this is where people will find the documents. 

Capital letters, No. then a space followed by a digit, open bracket, "Rev", stop, space, digit, close brackets. See below: 

Administrative Circular No. 25 (Rev. 3)



No hyphen is normally needed between an adverb and the adjective it modifies:

a hotly contested result

a constantly evolving theory

To avoid ambiguity, a hyphen is needed after adverbs such as “ill” and “well” that have the same spelling as the corresponding adjective, as in

a well-dressed man

an ill-considered reply

No hyphen is needed if the adverbial phrase comes after the noun, as in

the man was well dressed


Alpha Magnetic Spectrometer

Not Alphamagnetic Spectrometer.

physics, spelling, style

am and pm

See time


ampersand (&)

Don't use them, even in headlines. 


  • certain company names – Smith & Jones Consulting
  • when artistic considerations dictate – on a logo, for example 
  • academic references – (Grant & Smith, 1998)
punctuation, style


An important exception to the ize rule

spelling, style


Not anti-atom. Likewise antiparticle, antihydrogen, antineutrino, etc.

See antimatter

spelling, style


Not anti-matter. Likewise antiparticle, antihydrogen, antineutrino, etc.

See particles

spelling, style


Use the full word. Preferable to "about".

Don't abbreviate to "approx.", or worse, the symbol  "~".

The luminosity of the LHC has increased by approximately 16% over the last two months.



Symbol b.

A unit of area. A barn is 10−28 m2 (100 fm2), about the cross-sectional area of a uranium nucleus.

A barn expresses the cross section of any scattering process, which relates to the probability of interaction between small particles.

Sample size at CERN is often expressed in femtobarns and luminosity is expressed in inverse femtobarns.

physics, style


Adjective: baryonic

A subatomic particle, such as a nucleon or hyperon, that has a mass equal to or greater than that of a proton.



One word.

Note that the competition at CERN for high-school students is called Beamline for Schools – capital "B" and capital "S".

grammar, spelling


One word. See beamline


Big Bang

Upper case

physics, style


Means a thousand million, 109

See trillion

physics, style


The prefix bio takes no hyphen. So,







See footnotes



A subatomic particle, such as a photon, which has zero or integral spin and follows a statistical description given by SN Bose and Einstein.


brackets ( ) [ ]

Follow ODE's advice on brackets, copied here below:

There are two main types of brackets.

Round brackets

Round brackets (also called parentheses) are mainly used to separate off information that isn’t essential to the meaning of the rest of the sentence. If you removed the bracketed material the sentence would still make perfectly good sense. For example: 

Mount Everest (8848 metres) is the highest mountain in the world.

grammar, punctuation

Brout-Englert-Higgs mechanism

Not "Higgs mechanism" or "Higgs-Brout-Englert" mechanism. 

See Higgs boson


capital letters

Use minimal capitalization. A heading starts with a capital, but other words should not be capped up, unless they are proper nouns. If in doubt, choose lower case.

Exceptions include: our Sun, Earth (the planet), and our Solar System, but not universe, moon, earthquake, earth (the soil).

Use a capital letter when you are writing the names of people, languages, places, and words relating to them:

Africa, African
Buddha, Buddhism
Shakespeare, Shakespearean

punctuation, style



Use normal punctuation in captions, except at the end - No full stop at the end of the caption.

Image captions are a maximum of 200 characters (including spaces), and must include a credit in the format "(Image: Name/Organization)" Note there is no full stop after the parentheses at the end of the caption.


The image caption should be directly linked to the body text. So instead of:

The Antiproton Decelerator (Image: CERN)




The CERN Document Server.

See video.



Not centimeter. See units.


centre or center?

Only use the American spelling for American organizations and place names:

Centers for Disease Control and Prevention

Rockefeller Center

Otherwise, stick to centre:

The Sun is at the centre of our Solar System.



CERN, the European Organization for Nuclear Research, is the organization that operates the European Laboratory for Particle Physics. Lots of experiments take place at this laboratory.

Stick to the official title "European Organization for Nuclear Research" for CERN websites. 

Use the acronym CERN in the singular: 

CERN offers student work placements (not "CERN offer student work-placements")


CERN Council

Upper case for CERN Council.



CERN Data Centre

Formerly the CERN Computer Centre, the CERN Data Centre (CDC) forms Tier-0 of the Worldwide LHC Computing Grid. 

The change is to avoid confusion with the CERN Control Centre (CCC). 


Chemical compounds

Chemical compounds and alloys should be hyphenated, but the elements should not be capitalised:

The current in the dipole magnets is carried by cables made of niobium-titanium (NbTi).


Cherenkov radiation

Not Cerenkov. Though Cherenkov is a somewhat clumsy anglicization of the original Russian, the "Ch" ensures unambiguous pronunciation.

spelling, style


Note the hyphen.


collective nouns

Do they take a singular or plural verb? It depends on the sense, but use singular where possible.


Collide @ CERN

Capital C. The "At sign" in the name can sometimes cause problems with Drupal text formats. To get around this, whenever Collide @ CERN appears in text, separate the @ from the text with spaces.

Collide @ CERN is a 3-year artist’s residency programme at CERN.

spelling, style


The forceful striking together of two or more particles in the accelerator.

Define the type of collision using hyphens:

Lead-ion collisions are more complex and take longer to analyze than proton-proton collisions.


collision or event?

Use "collision" to refer to the exact point in time and space at which particles collide.

An "event" is a snapshot of what happens after a collision; an event is picked up by the detector: particles decay and their decay products form tracks or deposit energy in the detector.

Event displays from the detectors show the collision point in the middle - everything around it makes up the event.


collision point

The point in space within a particle detector at which two or more particles collide to form an event.


Don't use it. Use seminar instead.

See forbidden words


No Oxford comma: The good, the bad and the ugly

NOT the good, the bad, and the ugly

But make sure to add a comma after place names:

The computing school will take place in Uppsala, Sweden, on 16 March.



Contractions such as “there’s” “they’re”, “didn’t”, “he’ll”, “she’d” do not automatically make a story more accessible. Contractions can appear annoyingly chatty, and can be imprecise too (“it’s” can stand for “it is” or “it has”) and so detract from clarity. If anything, contractions make a story harder to understand, especially if there are several of them in the same sentence.

grammar, style


No hyphen.



Give figures in Swiss francs, then euros in brackets. 

"Five grams of enriched lead for the accelerator costs 12,000 CHF (9700)," says Kuchler. 

Use symbols and numerals when quoting specific amounts of common currencies:

£5 million (not 5 million pounds, or five million pounds)

€5 (not 5 euros or five euros)
about $3.5 billion (not about 3.5 billion dollars)


currency conversions

Amounts quoted in sterling, US dollars and euros do not normally need to be converted. The only exception might be if you want readers to be able to make direct comparisons between countries: if that applies you should choose one as the standard.

Any other currency should be converted the first time it is mentioned to the equivalent in US dollars. There are a number of currency converters on the net: covers any currency you are likely to encounter.



A cyclotron is an apparatus in which charged atomic and subatomic particles are accelerated by an alternating electric field while following an outward spiral or circular path in a magnetic field.

Perhaps the most important improvement has been the replacement of an electrical magnet with a series of permanent magnets to generate the cyclotron's magnetic field.



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