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John Donoghue

@jfdonoghue

Theoretical physics. University of Massachusetts. https://websites.umass.edu/donoghue/

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30.11.2023
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Latest posts by John Donoghue @jfdonoghue

I love the Friden mechanical calculator on her desk. I used one of these at one of my first jobs. When a slide rule was not accurate enough, this would chug away and give you an answer to many digits. Taking square roots it chugged for a long time.

20.02.2026 16:01 πŸ‘ 5 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0

My first talk about the paper was at Colorado and an hour before the talk I find out that Weinberg was visiting that day. Fortunately I had appropriately mentioned him in the intro. He was complementary after the talk and revised his colloquium to discuss what I had said.

12.02.2026 19:25 πŸ‘ 7 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

I gave a conference talk including GR at an EFT conference in Hungary a few years before my paper and the chiral folks’ reaction was sort of β€œso what - this is obvious - but you can’t measure anything”. Actually there is a history paper on the topic arxiv.org/pdf/2403.14008

12.02.2026 19:22 πŸ‘ 7 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Steve Weinberg made a comment of GR being an EFT in his 1979 paper on phenomenological Lagrangian. Most of the EFT work back then was on pion physics - chiral perturbation theory. That is where we learned how to do real calculations with it. No one was really talking about GR then.

12.02.2026 19:16 πŸ‘ 8 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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For 48 years, physicists largely ignored a theory of gravity that was riddled with ghosts, nonsensical-seeming particles that have a negative probability of arising. Recent work by John Donoghue and Gabriel Menezes has helped reinvigorate the theory. www.quantamagazine.org/old-ghost-th...

21.11.2025 16:46 πŸ‘ 13 πŸ” 8 πŸ’¬ 0 πŸ“Œ 0

This is a good article about a subtle topic in quantum gravity.

17.11.2025 15:44 πŸ‘ 5 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0

Thanks for the link. I did not know about that list.

06.11.2025 01:10 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Thanks Dan. It is definitely an honor to join the list of former recipients. (May I ask where you saw this - I have not seen it announced publicly yet.)

05.11.2025 19:59 πŸ‘ 5 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Seems problematic.

02.10.2025 22:14 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Did something happen recently?

02.10.2025 17:00 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Yes, I would expect it to be the Sommerfeld enhancement, but I was thinking that the top Higgs coupling was larger than its QCD coupling. And it should have a similar enhancement. Do we know how they compare in the actual amplitude?

08.07.2025 21:19 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Do you think that this if from Higgs exchange, which I think is stronger than QCD for the top quark at this energy?

08.07.2025 21:01 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Mine is shorter - I did not use a period. ( The arXiv refused to let me post with this abstract and made me say No in many words, so I am surprised that he got it past the ArXiv admin. The journal was happy to use it as written.)

www.actaphys.uj.edu.pl/fulltext?ser...

08.07.2025 12:23 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

This is my talk at the Campagna conference www.pifp2025.it/home

06.07.2025 14:43 πŸ‘ 9 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0

This was quite an interesting and well organized conference.

05.07.2025 21:49 πŸ‘ 4 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0

Incredibly stupid. Such a major investment, and tremendous output - one of biggest success stories of our time. To cut this at its peak output is a crime.

30.05.2025 23:38 πŸ‘ 6 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
$\ensuremath{\Delta}I=\frac{1}{2}$ Rule for Nonleptonic Decays in Asymptotically Free Field Theories The effective nonleptonic weak interaction is examined assuming the Weinberg-Salam theory of weak interactions and an exactly-conserved-color gauge symmetry for strong interactions. It is shown that t...

That one was indeed great. Also, their paper on the renormalization group of the weak nonleptonic Hamiltonian was a foundational classic.

journals.aps.org/prl/abstract...

25.05.2025 16:14 πŸ‘ 5 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

I haven’t seen it mentioned here yet, but we have gotten word from CERN that both Mary K Gaillard and Jonathan Rosner have died. Their paper with Ben Lee was the entry to charm physics for so many of us, but each had separately a large impact on particle physics.

25.05.2025 12:24 πŸ‘ 13 πŸ” 3 πŸ’¬ 2 πŸ“Œ 2

Yes this is incredibly damaging.

17.04.2025 19:37 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

These work very well. I brought several home from a recent trip. Why not in the US?

05.03.2025 21:07 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

It is a compilation of a lot of articles by many authors. All are on the arXiv. You can find many of them by using the search term Handbook of Quantum Gravity when searching via INSPIRE

01.03.2025 21:08 πŸ‘ 5 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0

Aren’t you likely to run into trouble with the Witten-Weinberg theorem when you try for a relativistic model of this type?

27.02.2025 00:00 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

The shape near the minimum needs to be a quadratic. Probably the first deviation from that is also fixed by the need for the Higgs potential to be part of a renormalizable Lagrangian. Can measurements of the shape really tell us much?

04.02.2025 00:40 πŸ‘ 4 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Probably Ampere rather than Lorentz

29.01.2025 23:39 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Great news! Gauge Theory of Elementary Particle Physics by Ta-Pei Cheng and Ling-Fong Li (Oxford) is now OPEN ACCESS! πŸŽ‰ You can read and download it for free using the PDF link below. πŸ“–βœ¨

fdslive.oup.com/www.oup.com/...

28.01.2025 04:22 πŸ‘ 34 πŸ” 17 πŸ’¬ 2 πŸ“Œ 0

Our expectation of background is the equivalent of an undergraduate Quantum Mechanic course. Two examples are the commutation relation of [x,p] and an introduction to perturbation theory.

26.01.2025 17:53 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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A Prelude to Quantum Field Theory A concise, beginner-friendly introduction to quantum field theory

I don't mean to keep harping on my books, but I just noticed that my QFT book with Lorenzo Sorbo "A Prelude to Quantum Field Theory" is presently discounted to only $22.37 on the Princeton University Press website. Seems to be a good price.
press.princeton.edu/books/ebook/...

25.01.2025 22:10 πŸ‘ 31 πŸ” 5 πŸ’¬ 1 πŸ“Œ 2
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Dynamics of the Standard Model Cambridge Core - Particle Physics and Nuclear Physics - Dynamics of the Standard Model

Maybe this is a good moment to reiterate that our book β€œDynamics of the Standard Model”, which Gene contributed so much to (including Barry Holstein), is available for free (open access) at Cambridge University Press.

www.cambridge.org/core/books/d...

21.01.2025 15:34 πŸ‘ 11 πŸ” 4 πŸ’¬ 0 πŸ“Œ 0

This was posted due to the news that Gene Golowich has passed away. A sad event an an end of an era for many of us.

21.01.2025 15:28 πŸ‘ 10 πŸ” 3 πŸ’¬ 2 πŸ“Œ 0

Thanks for highlighting this. I had felt that it was mostly forgotten. Also thanks for doing these posts throughout December - I have enjoyed them and saved many for further study.

29.12.2024 16:04 πŸ‘ 14 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0