LHC Symposium 2003: Summary Talk Page: 2 of 6
This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
EPJdirect Al, 1-11 (2003) Springer-Verlag
We also started to produce particles essentially undreamed of before - well,
dreamed of by only a few foolhardy visionaries. In addition to the pions at high pt
coming from hadronic interactions, a plethora of leptons appeared. Their num-
bers could not be explained by the decay of known strongly-produced particles.[3]
Eventually, these leptons were seen to come from the semileptonic decays of the
previously-unknown heavy quarks.
Perhaps the excess of leptons reminds you of the apparent excesses of heavy
quarks seen in hadronic interactions today (especially of B mesons and J/0
and 0' onia). It may be that what Mary Bishai referred to as a b-production
excess of 1.2-1.9 times theory,[4] will continue to fall as theoretical models of
production are refined. The fractional excess does seem to be coming down with
time. However, it is possible that we are already seeing the effects of something
which we will only understand once we have data from the LHC.
What happened when the big CERN and Fermilab hadron colliders turned
on? Available energy jumped from a few tens of GeV to 630 and 2,000 GeV.
Again, new energy territory opened for exploraton. We were again surprised
- maybe not so much by a new energy scale which was predicted (W and Z
masses), but by the very large mass of the top quark. I remember well, how
upon seeing evidence for the bottom quark, we immediately expected to see the
top quark at 7r times the mass of the bottom quark, just like the factor between
the bottom quark and the strange quark. The ratio of top to bottom quark
masses is more like 40 than 3! We do not understand why the top quark is so
heavy to this very day.
We have seen no direct evidence of any of the suggested new particles: not
sequential W or Z bosons, not Higgs, not SUSY, nor techni-particles. We have
not seen a break in pt spectra, nor the onset of a new level in the hierarchy
of matter, nor any suggestion of something more fundamental than quarks and
leptons.
2 How the Preparations are Going
As you have shown at this symposium, you are building detectors, and solving
technical and managerial problems. You are also building expanded collabora-
tions and new tools to deal with the new sociology: learning how to live with
larger and increasingly internationalized collaborations, learning new techniques
and tools for ever larger projects, and beginning to experiment with new com-
puting paradigms like GRID. [5, 6]
I have been impressed by the trigger tables shown and the expanding physics
goals shown by experiments. We had talks on heavy-ion collision measurements
in the big p - p detectors, ATLAS and CMS, detection of quark jets in ALICE,
and the appearance of B physics everywhere. Detectors have had design and
engineering updates, and simulations continue to include more complete detector
modeling. As usual, the results suggest somewhat less capability, but hopefully
more realistic expectations. At the same time, perhaps motivated in part by the
new understanding, better algorithms have been developed to compensate for
somewhat reduced detector expectations; e.g., in tracking and and heavy quark
tagging algorithms. In order to continue this progress, mock data challenge efforts
http://link.springer.de/link/service/journals/10105/index.html2
Upcoming Pages
Here’s what’s next.
Search Inside
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Appel, Jeffrey A. LHC Symposium 2003: Summary Talk, article, August 12, 2003; Batavia, Illinois. (https://digital.library.unt.edu/ark:/67531/metadc739713/m1/2/: accessed April 23, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.