(High-energy Theory Event Analyzer for collider processes)


The modern way of doing physics

This site is the public face of a novel approach for distributing and analyzing the results of fixed order NNLO calculations for LHC processes. Here are the main topics:



The basic idea

The idea behind HighTEA is very simple: existing calculations use Monte Carlo (MC) methods to integrate over the available phase space. Such MC samplings, called events, are usually binned in histograms and then discarded.

While very powerful, such an approach to doing high-precision NNLO calculations has a serious drawback: it lacks reusability. For example, if at a later time a new, often similar, calculation is required (we get a lot of these requests!) one has to compute the new request from scratch. Here is why this is problematic:

  • Public codes that can perform such NNLO calculations are scarce.
  • Any NNLO calculation is very time- and computing-resource- demanding. Typical costs are about 10k-50k CPU hours but could go into the millions. For such calculations large, cluster-size computing infrastructure is required. Not everyone has access to one, without even counting the associated expenses!
  • Such computing codes, even if made public, are too complicated for most users to use.

The following question then arises: is there a way to completely eliminate the above obstacles? The answer is yes!

As a result of many years of combined experience with developing and performing NNLO calculations our team has shown that it is possible to:

  • Store the events computed in a given calculation.
  • Ensure sustainable storage: not all computed events need to be stored thanks to a partial un-weighting technique we have employed. This way we can reduce the number of events that need to be stored which is essential for making the size of the database manageable.
  • Simple things should be simple: the users do not really need access to the events themselves. We have created our own sophisticated internal infrastructure, which allows the users to run their own analysis over the database of events without ever needing to worry about computing, infrastructure and associated costs. Users just request what they want and then receive their results, typically within minutes.


How it works

Here is what a typical HighTEA request looks like:

  • The user submits their request. Here is the info about how this is done.
  • The request automatically starts an analysis. It can take from few minutes to about half an hour depending on the requested options and how busy our servers are.
  • Once ready, the results are returned to the user in the form of histograms, potentially accompanied by a nice plot.

That’s it!


Main features

Here are some of HighTEA main features:

  • Any Infrared safe observable can be requested and binned.
  • The binning is defined in terms of kinematic variables. A set of predefined standard variables, specific to each process, are available to the user. The user can specify their own kinematic variables. The options are practically unlimited: any function available in the Python math library can be requested.
  • Arbitrary cuts can be implemented.
  • A major new feature of our library is that it allows users to specify any factorization and/or renormalization scales and parton distribution functions (pdf) used in their analysis. This makes it possible to obtain predictions based on any pdf set available in the LHAPDF library and any scales (standard ones, provided with HighTEA, or user defined ones).
  • All results returned by HighTEA contain an estimate of the statistical error due to the finite size of the event sample.
  • The results derived from HighTEA are as good as a brand new calculation started from scratch that has comparable statistics.
  • Users can analyze any one of the datasets that have been made available through HighTEA. The list of all available processes is available here.
  • We intend to constantly be adding new processes. Please let us know if your favorite process is not among the available ones.


How to access the library

There are two ways to access the library:

  • Via ready-to-use Jupyter notebooks on Google Colab. Suitable for all users. No special software or hardware infrastructure is required (it can even be accessed via standard smart phone). No programmatic skills are needed to fully utilize all available options.


Our Team

Meet the team:

To contact us, please email: hightea@hep.phy.cam.ac.uk



The results provided in this website, and in all linked sites, are free to use. Please kindly acknowledge HighTEA and all relevant publications utilized within HighTEA in your published work, press, etc.

Although all efforts have been made to ensure the results provided by HighTEA are correct, we do not warrant any results derived using HighTEA. Please let us know if you suspect bugs, etc.